diff --git a/.github/workflows/continuous-integration.yml b/.github/workflows/continuous-integration.yml
index f5a6a3e3b22..5d9d4428065 100644
--- a/.github/workflows/continuous-integration.yml
+++ b/.github/workflows/continuous-integration.yml
@@ -21,7 +21,6 @@ jobs:
           - macos-14
           - macos-15
         xcode:
-          - Xcode_15.2
           - Xcode_16.1
         destination:
           - 'platform=iOS Simulator,OS=17.2,name=iPhone 15'
@@ -32,12 +31,6 @@ jobs:
           - 'platform=visionOS Simulator,OS=2.1,name=Apple Vision Pro'
           - 'platform=macOS'
         exclude:
-          # Don't run old macOS with new Xcode
-          - runner: macos-14
-            xcode: Xcode_16.1
-          # Don't run new macOS with old Xcode
-          - runner: macos-15
-            xcode: Xcode_15.2
           # Don't run old simulators with new Xcode
           - destination: 'platform=tvOS Simulator,OS=17.2,name=Apple TV 4K (3rd generation) (at 1080p)'
             xcode: Xcode_16.1
@@ -45,13 +38,6 @@ jobs:
             xcode: Xcode_16.1
           - destination: 'platform=visionOS Simulator,OS=1.0,name=Apple Vision Pro'
             xcode: Xcode_16.1
-          # Don't run new simulators with old Xcode
-          - destination: 'platform=tvOS Simulator,OS=18.1,name=Apple TV 4K (3rd generation) (at 1080p)'
-            xcode: Xcode_15.2
-          - destination: 'platform=iOS Simulator,OS=18.1,name=iPhone 16'
-            xcode: Xcode_15.2
-          - destination: 'platform=visionOS Simulator,OS=2.1,name=Apple Vision Pro'
-            xcode: Xcode_15.2
     steps:
       - name: Configure Xcode
         run: sudo xcode-select -s /Applications/${{ matrix.xcode }}.app
@@ -140,7 +126,6 @@ jobs:
         os:
           - jammy
         version:
-          - "5.9"
           - "6.0"
     env:
       ACTIONS_ALLOW_USE_UNSECURE_NODE_VERSION: true
diff --git a/.github/workflows/integration-test.yml b/.github/workflows/integration-test.yml
index ec7ce42a0df..ec1d3d38017 100644
--- a/.github/workflows/integration-test.yml
+++ b/.github/workflows/integration-test.yml
@@ -26,7 +26,6 @@ jobs:
           - macos-14
           - macos-15
         xcode:
-          - Xcode_15.2
           - Xcode_16.1
         destination:
           - 'platform=iOS Simulator,OS=17.2,name=iPhone 15'
@@ -37,12 +36,6 @@ jobs:
           - 'platform=visionOS Simulator,OS=2.1,name=Apple Vision Pro'
           - 'platform=macOS'
         exclude:
-          # Don't run old macOS with new Xcode
-          - runner: macos-14
-            xcode: Xcode_16.1
-          # Don't run new macOS with old Xcode
-          - runner: macos-15
-            xcode: Xcode_15.2
           # Don't run old simulators with new Xcode
           - destination: 'platform=tvOS Simulator,OS=17.2,name=Apple TV 4K (3rd generation) (at 1080p)'
             xcode: Xcode_16.1
@@ -50,13 +43,6 @@ jobs:
             xcode: Xcode_16.1
           - destination: 'platform=visionOS Simulator,OS=1.0,name=Apple Vision Pro'
             xcode: Xcode_16.1
-          # Don't run new simulators with old Xcode
-          - destination: 'platform=tvOS Simulator,OS=18.1,name=Apple TV 4K (3rd generation) (at 1080p)'
-            xcode: Xcode_15.2
-          - destination: 'platform=iOS Simulator,OS=18.1,name=iPhone 16'
-            xcode: Xcode_15.2
-          - destination: 'platform=visionOS Simulator,OS=2.1,name=Apple Vision Pro'
-            xcode: Xcode_15.2
     steps:
       - name: Configure Xcode
         run: sudo xcode-select -s /Applications/${{ matrix.xcode }}.app
@@ -76,6 +62,8 @@ jobs:
         uses: actions/checkout@v4
         with:
           path: aws-sdk-swift
+          ref: ${{ github.event.pull_request.head.sha || github.ref }}
+          fetch-depth: 0
       - name: Checkout smithy-swift with composite action
         uses: ./aws-sdk-swift/.github/actions/checkout-smithy-swift-composite-action
         with:
@@ -132,8 +120,7 @@ jobs:
             -scheme AWSIntegrationTestsOnCI \
             -testPlan AWSIntegrationTestsOnCI \
             -destination '${{ matrix.destination }}' \
-            test 2>&1 \
-            | xcbeautify
+            test 2>&1
 
   linux:
     # Details on why AL2 isn't included: https://github.com/awslabs/aws-sdk-swift/pull/1833
@@ -146,7 +133,6 @@ jobs:
         os:
           - jammy
         version:
-          - "5.9"
           - "6.0"
     env:
       ACTIONS_ALLOW_USE_UNSECURE_NODE_VERSION: true
@@ -162,6 +148,8 @@ jobs:
         uses: actions/checkout@v4
         with:
           path: aws-sdk-swift
+          ref: ${{ github.event.pull_request.head.sha || github.ref }}
+          fetch-depth: 0
       - name: Checkout smithy-swift with composite action
         uses: ./aws-sdk-swift/.github/actions/checkout-smithy-swift-composite-action
         with:
diff --git a/AWSSDKSwiftCLI/Sources/AWSSDKSwiftCLI/Resources/Package.Base.txt b/AWSSDKSwiftCLI/Sources/AWSSDKSwiftCLI/Resources/Package.Base.txt
index 84d0179a906..e51749d2a61 100644
--- a/AWSSDKSwiftCLI/Sources/AWSSDKSwiftCLI/Resources/Package.Base.txt
+++ b/AWSSDKSwiftCLI/Sources/AWSSDKSwiftCLI/Resources/Package.Base.txt
@@ -84,7 +84,7 @@ private var clientRuntimeDependency: Package.Dependency {
 }
 
 private var crtDependency: Package.Dependency {
-    .package(url: "https://github.com/awslabs/aws-crt-swift", exact: crtVersion)
+    .package(url: "https://github.com/awslabs/aws-crt-swift", branch: "swift6-support")
 }
 
 private var doccDependencyOrNil: Package.Dependency? {
diff --git a/AWSSDKSwiftCLI/Sources/AWSSDKSwiftCLI/Resources/Package.Prefix.txt b/AWSSDKSwiftCLI/Sources/AWSSDKSwiftCLI/Resources/Package.Prefix.txt
index e213f85e5be..b8c118be41a 100644
--- a/AWSSDKSwiftCLI/Sources/AWSSDKSwiftCLI/Resources/Package.Prefix.txt
+++ b/AWSSDKSwiftCLI/Sources/AWSSDKSwiftCLI/Resources/Package.Prefix.txt
@@ -1,4 +1,4 @@
-// swift-tools-version:5.9
+// swift-tools-version:6.0
 
 //
 // Copyright Amazon.com Inc. or its affiliates.
diff --git a/IntegrationTests/AWSIntegrationTestUtils/ConcurrentTestHelper.swift b/IntegrationTests/AWSIntegrationTestUtils/ConcurrentTestHelper.swift
index 19b461b2926..5830eafcf4b 100644
--- a/IntegrationTests/AWSIntegrationTestUtils/ConcurrentTestHelper.swift
+++ b/IntegrationTests/AWSIntegrationTestUtils/ConcurrentTestHelper.swift
@@ -13,7 +13,10 @@
 ///   - count: The number of test runs
 ///   - test: The function pointer for the test to run
 /// - Throws: Any error thrown by one of the test runs.
-public func repeatConcurrently(count: Int, test: @escaping () async throws -> Void) async throws {
+public func repeatConcurrently(
+    count: Int,
+    test: @escaping @Sendable () async throws -> Void
+) async throws {
     try await withThrowingTaskGroup(of: Void.self) { taskGroup in
         for _ in 0..<count {
             taskGroup.addTask {
@@ -33,15 +36,15 @@ public func repeatConcurrently(count: Int, test: @escaping () async throws -> Vo
 ///   - test: The function pointer for the test to run
 ///   - args: Any values to pass along to test function
 /// - Throws: Any error thrown by one of the test runs.
-public func repeatConcurrentlyWithArgs(
+public func repeatConcurrentlyWithArgs<Arg: Sendable>(
     count: Int,
-    test: @escaping (Any...) async throws -> Void,
-    args: Any...
+    test: @escaping @Sendable (Arg) async throws -> Void,
+    arg: Arg
 ) async throws {
     try await withThrowingTaskGroup(of: Void.self) { taskGroup in
         for _ in 0..<count {
             taskGroup.addTask {
-                try await test(args)
+                try await test(arg)
             }
         }
         try await taskGroup.waitForAll()
diff --git a/IntegrationTests/Package.swift b/IntegrationTests/Package.swift
index 539fbfa6c64..23f7853e340 100644
--- a/IntegrationTests/Package.swift
+++ b/IntegrationTests/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version:5.9
+// swift-tools-version:6.0
 
 //
 // Copyright Amazon.com Inc. or its affiliates.
diff --git a/IntegrationTests/Services/AWSS3IntegrationTests/S3ConcurrentTests.swift b/IntegrationTests/Services/AWSS3IntegrationTests/S3ConcurrentTests.swift
index 8c09d7cfcfb..7664f27859a 100644
--- a/IntegrationTests/Services/AWSS3IntegrationTests/S3ConcurrentTests.swift
+++ b/IntegrationTests/Services/AWSS3IntegrationTests/S3ConcurrentTests.swift
@@ -12,57 +12,46 @@ import XCTest
 import AWSS3
 import AWSIntegrationTestUtils
 
-final class S3ConcurrentTests: S3XCTestCase {
+final class S3ConcurrentTests: S3XCTestCase, @unchecked Sendable {
     private var fileData: Data!
 
     // Payload just below chunked threshold
     // Tests concurrent upload of simple data payloads
     func test_10x_1MB_getObject() async throws {
         fileData = generateRandomTextData(ofSizeInMB: 1)
-        try await repeatConcurrentlyWithArgs(count: 10, test: getObject, args: fileData!)
+        try await repeatConcurrentlyWithArgs(count: 10, test: getObject, arg: fileData!)
     }
 
     // Payload at chunked threshold, just large enough to chunk
     // Tests concurrent upload with aws-chunked encoding & flexible checksums
     func test_10x_1_5MB_getObject() async throws {
         fileData = generateRandomTextData(ofSizeInMB: 1.5)
-        try await repeatConcurrentlyWithArgs(count: 10, test: getObject, args: fileData!)
+        try await repeatConcurrentlyWithArgs(count: 10, test: getObject, arg: fileData!)
     }
 
     // Payload 256 bytes with 200 concurrent requests, sends as simple data
     // Tests very high concurrency with small data payloads
     func test_200x_256B_getObject() async throws {
         fileData = generateRandomTextData(ofSizeInBytes: 256)
-        try await repeatConcurrentlyWithArgs(count: 200, test: getObject, args: fileData!)
+        try await repeatConcurrentlyWithArgs(count: 200, test: getObject, arg: fileData!)
     }
 
     // MARK: - Private methods
 
     // Puts data to S3, gets the uploaded file, asserts retrieved data == original data, deletes S3 object
-    private func getObject(args: Any...) async throws {
+    private func getObject(data: Data) async throws {
+       let objectKey = UUID().uuidString.split(separator: "-").first!.lowercased()
+       let putObjectInput = PutObjectInput(body: .data(data), bucket: bucketName, key: objectKey)
 
-        // Take the test data and crate a PutObject request to send it
-        guard let data = args[0] as? Data else {
-            throw ClientError.dataNotFound("Failed to retrieve dummy data.")
-        }
-        let file = ByteStream.data(data)
-        let objectKey = UUID().uuidString.split(separator: "-").first!.lowercased()
-        let putObjectInput = PutObjectInput(body: file, bucket: bucketName, key: objectKey)
+       _ = try await client.putObject(input: putObjectInput)
 
-        // Put the test data to S3
-        _ = try await client.putObject(input: putObjectInput)
+       let retrievedData = try await client.getObject(input: GetObjectInput(
+           bucket: bucketName, key: objectKey
+       )).body?.readData()
 
-        // Read the response's data stream into memory
-        let retrievedData = try await client.getObject(input: GetObjectInput(
-            bucket: bucketName, key: objectKey
-        )).body?.readData()
+       XCTAssertEqual(data, retrievedData)
 
-        // Compare the retrieved data to the uploaded data to show they are equal
-        XCTAssertEqual(data, retrievedData)
-
-        // Delete the S3 object once the test has been verified
-        // Calling DeleteObject here allows for concurrent deletion, accelerating test teardown
-        let deleteObjectInput = DeleteObjectInput(bucket: bucketName, key: objectKey)
-        _ = try await client.deleteObject(input: deleteObjectInput)
-    }
+       let deleteObjectInput = DeleteObjectInput(bucket: bucketName, key: objectKey)
+       _ = try await client.deleteObject(input: deleteObjectInput)
+   }
 }
diff --git a/IntegrationTests/Services/AWSS3IntegrationTests/S3XCTestCase.swift b/IntegrationTests/Services/AWSS3IntegrationTests/S3XCTestCase.swift
index e8c1b7968c4..4a762f09ffb 100644
--- a/IntegrationTests/Services/AWSS3IntegrationTests/S3XCTestCase.swift
+++ b/IntegrationTests/Services/AWSS3IntegrationTests/S3XCTestCase.swift
@@ -14,9 +14,8 @@ import AWSS3
 /// Provides a basic set of functions that can be used to perform S3 integration tests.
 /// Creates a bucket for testing before every test, then deletes the bucket after the test completes.
 class S3XCTestCase: XCTestCase {
-    static var client: S3Client!
     static let region = "us-west-2"
-    var client: S3Client { Self.client }
+    var client: S3Client!
     var region: String { Self.region }
     var bucketName: String!
 
@@ -39,14 +38,14 @@ class S3XCTestCase: XCTestCase {
 
     override func setUp() async throws{
         self.bucketName = "aws-sdk-s3-integration-test-\(UUID().uuidString.split(separator: "-").first!.lowercased())"
-        Self.client = try S3Client(region: region)
-        try await Self.createBucket(bucketName: bucketName)
+        self.client = try S3Client(region: region)
+        try await createBucket(bucketName: bucketName)
     }
 
     /// Empty & delete the test bucket before each test.
     override func tearDown() async throws {
         try await emptyBucket()
-        try await Self.deleteBucket(bucketName: bucketName)
+        try await deleteBucket(bucketName: bucketName)
     }
 
     // MARK: Helpers
@@ -73,9 +72,9 @@ class S3XCTestCase: XCTestCase {
         }
     }
 
-    static func createBucket(bucketName: String) async throws {
+    func createBucket(bucketName: String) async throws {
         let input = CreateBucketInput(bucket: bucketName, createBucketConfiguration: S3ClientTypes.CreateBucketConfiguration(locationConstraint: S3ClientTypes.BucketLocationConstraint.usWest2))
-        _ = try await Self.client.createBucket(input: input)
+        _ = try await self.client.createBucket(input: input)
     }
 
     func putObject(body: String, key: String) async throws {
@@ -112,7 +111,7 @@ class S3XCTestCase: XCTestCase {
         }
     }
 
-    static func deleteBucket(bucketName: String) async throws {
+    func deleteBucket(bucketName: String) async throws {
         let input = DeleteBucketInput(bucket: bucketName)
         _ = try await client.deleteBucket(input: input)
     }
diff --git a/IntegrationTests/Services/AWSTranscribeStreamingIntegrationTests/TranscribeStreamingTests.swift b/IntegrationTests/Services/AWSTranscribeStreamingIntegrationTests/TranscribeStreamingTests.swift
index 701db720273..aab14fd2a76 100644
--- a/IntegrationTests/Services/AWSTranscribeStreamingIntegrationTests/TranscribeStreamingTests.swift
+++ b/IntegrationTests/Services/AWSTranscribeStreamingIntegrationTests/TranscribeStreamingTests.swift
@@ -11,7 +11,7 @@ import Foundation
 import AWSTranscribeStreaming
 import protocol AWSClientRuntime.AWSServiceError
 
-final class TranscribeStreamingTests: XCTestCase {
+final class TranscribeStreamingTests: XCTestCase, @unchecked Sendable {
 
     // MARK: - Test transcription
 
diff --git a/Package.resolved b/Package.resolved
new file mode 100644
index 00000000000..44e822f0b5c
--- /dev/null
+++ b/Package.resolved
@@ -0,0 +1,33 @@
+{
+  "originHash" : "1fdaa55664cdad23f69d7841f64fc8963c8731108c2d485a300429c13912b3ae",
+  "pins" : [
+    {
+      "identity" : "aws-crt-swift",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/awslabs/aws-crt-swift",
+      "state" : {
+        "branch" : "swift6-support",
+        "revision" : "f7ea06a571f64c12b501d3a3ad772eee94f547a5"
+      }
+    },
+    {
+      "identity" : "swift-argument-parser",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-argument-parser.git",
+      "state" : {
+        "revision" : "41982a3656a71c768319979febd796c6fd111d5c",
+        "version" : "1.5.0"
+      }
+    },
+    {
+      "identity" : "swift-log",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-log.git",
+      "state" : {
+        "revision" : "3d8596ed08bd13520157f0355e35caed215ffbfa",
+        "version" : "1.6.3"
+      }
+    }
+  ],
+  "version" : 3
+}
diff --git a/Package.swift b/Package.swift
index 4804cfdcfc3..86e0f359e21 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version:5.9
+// swift-tools-version:6.0
 
 //
 // Copyright Amazon.com Inc. or its affiliates.
@@ -514,7 +514,7 @@ private var clientRuntimeDependency: Package.Dependency {
 }
 
 private var crtDependency: Package.Dependency {
-    .package(url: "https://github.com/awslabs/aws-crt-swift", exact: crtVersion)
+    .package(url: "https://github.com/awslabs/aws-crt-swift", branch: "swift6-support")
 }
 
 private var doccDependencyOrNil: Package.Dependency? {
diff --git a/PerformanceTests/Package.swift b/PerformanceTests/Package.swift
index c2f03374ea2..5744de7514f 100644
--- a/PerformanceTests/Package.swift
+++ b/PerformanceTests/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version: 5.9
+// swift-tools-version: 6.0
 
 import PackageDescription
 
diff --git a/Sources/Core/AWSClientRuntime/Package.swift.txt b/Sources/Core/AWSClientRuntime/Package.swift.txt
index 6ff028b3ac0..41124685c32 100644
--- a/Sources/Core/AWSClientRuntime/Package.swift.txt
+++ b/Sources/Core/AWSClientRuntime/Package.swift.txt
@@ -1,4 +1,4 @@
-// swift-tools-version: 5.9
+// swift-tools-version: 6.0
 
 import PackageDescription
 
diff --git a/Sources/Core/AWSClientRuntime/Sources/AWSClientRuntime/Endpoints/AccountIDEndpointMode.swift b/Sources/Core/AWSClientRuntime/Sources/AWSClientRuntime/Endpoints/AccountIDEndpointMode.swift
index 8ac03ca6ebf..dbdcc1db3cb 100644
--- a/Sources/Core/AWSClientRuntime/Sources/AWSClientRuntime/Endpoints/AccountIDEndpointMode.swift
+++ b/Sources/Core/AWSClientRuntime/Sources/AWSClientRuntime/Endpoints/AccountIDEndpointMode.swift
@@ -6,7 +6,7 @@
 //
 
 /// Determines how & whether an account ID-based endpoint will be used for requests.
-public enum AccountIDEndpointMode: String, Equatable {
+public enum AccountIDEndpointMode: String, Equatable, Sendable {
     // Note : these case names match string values for the accountIdEndpointMode endpoint param.
     // Do not rename them
 
diff --git a/Sources/Core/AWSSDKChecksums/Package.swift.txt b/Sources/Core/AWSSDKChecksums/Package.swift.txt
index 999e4d8a110..f01945f56f9 100644
--- a/Sources/Core/AWSSDKChecksums/Package.swift.txt
+++ b/Sources/Core/AWSSDKChecksums/Package.swift.txt
@@ -1,4 +1,4 @@
-// swift-tools-version: 5.9
+// swift-tools-version: 6.0
 
 import PackageDescription
 
diff --git a/Sources/Core/AWSSDKChecksums/Sources/AWSSDKChecksums/AWSChecksumCalculationMode.swift b/Sources/Core/AWSSDKChecksums/Sources/AWSSDKChecksums/AWSChecksumCalculationMode.swift
index 70c2d490cf9..7b0586114c8 100644
--- a/Sources/Core/AWSSDKChecksums/Sources/AWSSDKChecksums/AWSChecksumCalculationMode.swift
+++ b/Sources/Core/AWSSDKChecksums/Sources/AWSSDKChecksums/AWSChecksumCalculationMode.swift
@@ -5,7 +5,7 @@
 // SPDX-License-Identifier: Apache-2.0
 //
 
-public enum AWSChecksumCalculationMode: String {
+public enum AWSChecksumCalculationMode: String, Sendable {
     case whenRequired = "when_required"
     case whenSupported = "when_supported"
 
diff --git a/Sources/Core/AWSSDKCommon/Package.swift.txt b/Sources/Core/AWSSDKCommon/Package.swift.txt
index 37e3a8b9101..fab3af01ff6 100644
--- a/Sources/Core/AWSSDKCommon/Package.swift.txt
+++ b/Sources/Core/AWSSDKCommon/Package.swift.txt
@@ -1,4 +1,4 @@
-// swift-tools-version: 5.9
+// swift-tools-version: 6.0
 
 import PackageDescription
 
diff --git a/Sources/Core/AWSSDKEventStreamsAuth/Package.swift.txt b/Sources/Core/AWSSDKEventStreamsAuth/Package.swift.txt
index e112cd9014b..e019179aa93 100644
--- a/Sources/Core/AWSSDKEventStreamsAuth/Package.swift.txt
+++ b/Sources/Core/AWSSDKEventStreamsAuth/Package.swift.txt
@@ -1,4 +1,4 @@
-// swift-tools-version: 5.9
+// swift-tools-version: 6.0
 
 import PackageDescription
 
diff --git a/Sources/Core/AWSSDKEventStreamsAuth/Sources/AWSSSDKEventStreamsAuth/AWSMessageSigner.swift b/Sources/Core/AWSSDKEventStreamsAuth/Sources/AWSSSDKEventStreamsAuth/AWSMessageSigner.swift
index 07ccbebb78d..a7135c970c9 100644
--- a/Sources/Core/AWSSDKEventStreamsAuth/Sources/AWSSSDKEventStreamsAuth/AWSMessageSigner.swift
+++ b/Sources/Core/AWSSDKEventStreamsAuth/Sources/AWSSSDKEventStreamsAuth/AWSMessageSigner.swift
@@ -15,11 +15,11 @@ import struct Smithy.Attributes
 import struct Smithy.AttributeKey
 
 /// Signs a `Message` using the AWS SigV4 signing algorithm
-public class AWSMessageSigner: MessageSigner {
+public actor AWSMessageSigner: MessageSigner {
     let encoder: MessageEncoder
-    let signer: () async throws -> MessageDataSigner
-    let signingConfig: () async throws -> AWSSigningConfig
-    let requestSignature: () -> String
+    let signer: @Sendable () async throws -> MessageDataSigner
+    let signingConfig: @Sendable () async throws -> AWSSigningConfig
+    let requestSignature: @Sendable () -> String
     // Attribute key used to save AWSSigningConfig into signingProperties argument
     //  for AWSSigV4Signer::signEvent call that conforms to Signer::signEvent.
     static let signingConfigKey = AttributeKey<AWSSigningConfig>(name: "EventStreamSigningConfig")
@@ -45,9 +45,9 @@ public class AWSMessageSigner: MessageSigner {
     }
 
     public init(encoder: MessageEncoder,
-                signer: @escaping () async throws -> MessageDataSigner,
-                signingConfig: @escaping () async throws -> AWSSigningConfig,
-                requestSignature: @escaping () -> String) {
+                signer: @escaping @Sendable () async throws -> MessageDataSigner,
+                signingConfig: @escaping @Sendable () async throws -> AWSSigningConfig,
+                requestSignature: @escaping @Sendable () -> String) {
         self.encoder = encoder
         self.signer = signer
         self.signingConfig = signingConfig
diff --git a/Sources/Core/AWSSDKEventStreamsAuth/Tests/AWSSDKEventStreamsAuthTests/TestCustomAWSCredentialIdentityResolver.swift b/Sources/Core/AWSSDKEventStreamsAuth/Tests/AWSSDKEventStreamsAuthTests/TestCustomAWSCredentialIdentityResolver.swift
index 4a67919cef5..44e99537367 100644
--- a/Sources/Core/AWSSDKEventStreamsAuth/Tests/AWSSDKEventStreamsAuthTests/TestCustomAWSCredentialIdentityResolver.swift
+++ b/Sources/Core/AWSSDKEventStreamsAuth/Tests/AWSSDKEventStreamsAuthTests/TestCustomAWSCredentialIdentityResolver.swift
@@ -8,7 +8,7 @@
 import Smithy
 import SmithyIdentity
 
-class TestCustomAWSCredentialIdentityResolver: AWSCredentialIdentityResolver {
+class TestCustomAWSCredentialIdentityResolver: AWSCredentialIdentityResolver, @unchecked Sendable {
     let credentials: AWSCredentialIdentity
 
     init(credentials: AWSCredentialIdentity) {
diff --git a/Sources/Core/AWSSDKHTTPAuth/Package.swift.txt b/Sources/Core/AWSSDKHTTPAuth/Package.swift.txt
index 76728defcc9..b20eec4c7f7 100644
--- a/Sources/Core/AWSSDKHTTPAuth/Package.swift.txt
+++ b/Sources/Core/AWSSDKHTTPAuth/Package.swift.txt
@@ -1,4 +1,4 @@
-// swift-tools-version: 5.9
+// swift-tools-version: 6.0
 
 import PackageDescription
 
diff --git a/Sources/Core/AWSSDKHTTPAuth/Sources/AWSSDKHTTPAuth/AWSSigV4Signer.swift b/Sources/Core/AWSSDKHTTPAuth/Sources/AWSSDKHTTPAuth/AWSSigV4Signer.swift
index 635c96d1f0b..c71e9562999 100644
--- a/Sources/Core/AWSSDKHTTPAuth/Sources/AWSSDKHTTPAuth/AWSSigV4Signer.swift
+++ b/Sources/Core/AWSSDKHTTPAuth/Sources/AWSSDKHTTPAuth/AWSSigV4Signer.swift
@@ -32,7 +32,7 @@ import struct Foundation.TimeInterval
 import struct Foundation.URL
 import AWSSDKChecksums
 
-public class AWSSigV4Signer: SmithyHTTPAuthAPI.Signer {
+public final class AWSSigV4Signer: SmithyHTTPAuthAPI.Signer, Sendable {
 
     public init() {}
 
diff --git a/Sources/Core/AWSSDKHTTPAuth/Tests/AWSSDKHTTPAuthTests/SigV4SigningTests.swift b/Sources/Core/AWSSDKHTTPAuth/Tests/AWSSDKHTTPAuthTests/SigV4SigningTests.swift
index 06cbf0a6891..4ba899ad924 100644
--- a/Sources/Core/AWSSDKHTTPAuth/Tests/AWSSDKHTTPAuthTests/SigV4SigningTests.swift
+++ b/Sources/Core/AWSSDKHTTPAuth/Tests/AWSSDKHTTPAuthTests/SigV4SigningTests.swift
@@ -302,7 +302,7 @@ class Sigv4SigningTests: XCTestCase {
     }
 }
 
-class TestCustomAWSCredentialIdentityResolver: AWSCredentialIdentityResolver {
+class TestCustomAWSCredentialIdentityResolver: AWSCredentialIdentityResolver, @unchecked Sendable {
     let credentials: AWSCredentialIdentity
     
     init(credentials: AWSCredentialIdentity) {
diff --git a/Sources/Core/AWSSDKIdentity/Package.swift.txt b/Sources/Core/AWSSDKIdentity/Package.swift.txt
index 0a7f692819e..e4ffd72a38f 100644
--- a/Sources/Core/AWSSDKIdentity/Package.swift.txt
+++ b/Sources/Core/AWSSDKIdentity/Package.swift.txt
@@ -1,4 +1,4 @@
-// swift-tools-version: 5.9
+// swift-tools-version: 6.0
 
 import PackageDescription
 
diff --git a/Sources/Core/AWSSDKIdentity/Tests/AWSSDKIdentityTests/AWSCredentialIdentityResolverTests/CachedAWSCredentialIdentityResolverTests.swift b/Sources/Core/AWSSDKIdentity/Tests/AWSSDKIdentityTests/AWSCredentialIdentityResolverTests/CachedAWSCredentialIdentityResolverTests.swift
index aef18f050d8..81cec9573e3 100644
--- a/Sources/Core/AWSSDKIdentity/Tests/AWSSDKIdentityTests/AWSCredentialIdentityResolverTests/CachedAWSCredentialIdentityResolverTests.swift
+++ b/Sources/Core/AWSSDKIdentity/Tests/AWSSDKIdentityTests/AWSCredentialIdentityResolverTests/CachedAWSCredentialIdentityResolverTests.swift
@@ -10,13 +10,25 @@ import struct AWSSDKIdentity.CachedAWSCredentialIdentityResolver
 
 class CachedAWSCredentialIdentityResolverTests: XCTestCase {
 
+    actor Counter {
+        private var value: Int = 0
+
+        func increment() {
+            value += 1
+        }
+
+        func get() -> Int {
+            return value
+        }
+    }
+
     func testGetIdentity() async throws {
-        var counter: Int = 0
+        let counter = Counter()
         let accessKey = UUID().uuidString
         let secret = UUID().uuidString
         let accountID = UUID().uuidString
         let coreProvider = MockAWSCredentialIdentityResolver {
-            counter += 1
+            await counter.increment()
             return .init(accessKey: accessKey, secret: secret, accountID: accountID)
         }
         let subject = try CachedAWSCredentialIdentityResolver(
@@ -30,13 +42,15 @@ class CachedAWSCredentialIdentityResolverTests: XCTestCase {
         _ = try await subject.getIdentity()
 
         // Counter is 1 because the last three accesses use cached credentials
-        XCTAssertEqual(counter, 1)
+        let finalCount = await counter.get()
+        XCTAssertEqual(finalCount, 1)
 
         try! await Task.sleep(nanoseconds: 1_000_000_000 / 100)  // 0.01 seconds
         let credentials = try await subject.getIdentity()
 
         // Counter is 2 because we slept long enough for cache to expire
-        XCTAssertEqual(counter, 2)
+        let countAfterSleep = await counter.get()
+        XCTAssertEqual(countAfterSleep, 2)
         XCTAssertEqual(credentials.accessKey, accessKey)
         XCTAssertEqual(credentials.secret, secret)
         XCTAssertEqual(credentials.accountID, accountID)
diff --git a/Sources/Core/AWSSDKIdentity/Tests/AWSSDKIdentityTests/Mocks/MockAWSCredentialIdentityResolver.swift b/Sources/Core/AWSSDKIdentity/Tests/AWSSDKIdentityTests/Mocks/MockAWSCredentialIdentityResolver.swift
index 9adb38ebea9..5721737f742 100644
--- a/Sources/Core/AWSSDKIdentity/Tests/AWSSDKIdentityTests/Mocks/MockAWSCredentialIdentityResolver.swift
+++ b/Sources/Core/AWSSDKIdentity/Tests/AWSSDKIdentityTests/Mocks/MockAWSCredentialIdentityResolver.swift
@@ -10,8 +10,8 @@ import struct SmithyIdentity.AWSCredentialIdentity
 import protocol SmithyIdentity.AWSCredentialIdentityResolver
 
 struct MockAWSCredentialIdentityResolver: AWSCredentialIdentityResolver {
-    let _getIdentity: () async throws -> AWSCredentialIdentity
-    init(_ _getIdentity: @escaping () async throws -> AWSCredentialIdentity) {
+    let _getIdentity: @Sendable () async throws -> AWSCredentialIdentity
+    init(_ _getIdentity: @escaping @Sendable () async throws -> AWSCredentialIdentity) {
         self._getIdentity = _getIdentity
     }
     init() {
diff --git a/Sources/Services/AWSACM/Sources/AWSACM/Endpoints.swift b/Sources/Services/AWSACM/Sources/AWSACM/Endpoints.swift
index e6d1051abb1..50eaeb18485 100644
--- a/Sources/Services/AWSACM/Sources/AWSACM/Endpoints.swift
+++ b/Sources/Services/AWSACM/Sources/AWSACM/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSACM/Tests/AWSACMTests/EndpointResolverTest.swift b/Sources/Services/AWSACM/Tests/AWSACMTests/EndpointResolverTest.swift
index 506e8d0e6a5..783652d21d2 100644
--- a/Sources/Services/AWSACM/Tests/AWSACMTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSACM/Tests/AWSACMTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSACM
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -830,7 +831,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -869,7 +870,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -947,7 +948,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSACMPCA/Sources/AWSACMPCA/Endpoints.swift b/Sources/Services/AWSACMPCA/Sources/AWSACMPCA/Endpoints.swift
index b79ef94def9..3fcee7f60e0 100644
--- a/Sources/Services/AWSACMPCA/Sources/AWSACMPCA/Endpoints.swift
+++ b/Sources/Services/AWSACMPCA/Sources/AWSACMPCA/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSACMPCA/Tests/AWSACMPCATests/EndpointResolverTest.swift b/Sources/Services/AWSACMPCA/Tests/AWSACMPCATests/EndpointResolverTest.swift
index b258f445d9a..8c957328659 100644
--- a/Sources/Services/AWSACMPCA/Tests/AWSACMPCATests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSACMPCA/Tests/AWSACMPCATests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSACMPCA
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -830,7 +831,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -869,7 +870,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -947,7 +948,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAPIGateway/Sources/AWSAPIGateway/Endpoints.swift b/Sources/Services/AWSAPIGateway/Sources/AWSAPIGateway/Endpoints.swift
index bc4acae8293..eec28046038 100644
--- a/Sources/Services/AWSAPIGateway/Sources/AWSAPIGateway/Endpoints.swift
+++ b/Sources/Services/AWSAPIGateway/Sources/AWSAPIGateway/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAPIGateway/Tests/AWSAPIGatewayTests/EndpointResolverTest.swift b/Sources/Services/AWSAPIGateway/Tests/AWSAPIGatewayTests/EndpointResolverTest.swift
index 4cc56c96999..645d0ffc097 100644
--- a/Sources/Services/AWSAPIGateway/Tests/AWSAPIGatewayTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAPIGateway/Tests/AWSAPIGatewayTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAPIGateway
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -750,7 +751,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -808,7 +809,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -847,7 +848,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -868,7 +869,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSARCZonalShift/Sources/AWSARCZonalShift/Endpoints.swift b/Sources/Services/AWSARCZonalShift/Sources/AWSARCZonalShift/Endpoints.swift
index 0067f58573e..604f40928a4 100644
--- a/Sources/Services/AWSARCZonalShift/Sources/AWSARCZonalShift/Endpoints.swift
+++ b/Sources/Services/AWSARCZonalShift/Sources/AWSARCZonalShift/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSARCZonalShift/Tests/AWSARCZonalShiftTests/EndpointResolverTest.swift b/Sources/Services/AWSARCZonalShift/Tests/AWSARCZonalShiftTests/EndpointResolverTest.swift
index dfd5a287e76..607b345518f 100644
--- a/Sources/Services/AWSARCZonalShift/Tests/AWSARCZonalShiftTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSARCZonalShift/Tests/AWSARCZonalShiftTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSARCZonalShift
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAccessAnalyzer/Sources/AWSAccessAnalyzer/Endpoints.swift b/Sources/Services/AWSAccessAnalyzer/Sources/AWSAccessAnalyzer/Endpoints.swift
index 12162ab23a7..ba8fbbe40e7 100644
--- a/Sources/Services/AWSAccessAnalyzer/Sources/AWSAccessAnalyzer/Endpoints.swift
+++ b/Sources/Services/AWSAccessAnalyzer/Sources/AWSAccessAnalyzer/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAccessAnalyzer/Tests/AWSAccessAnalyzerTests/EndpointResolverTest.swift b/Sources/Services/AWSAccessAnalyzer/Tests/AWSAccessAnalyzerTests/EndpointResolverTest.swift
index 77c4ddd2fb8..f6db05d1e2f 100644
--- a/Sources/Services/AWSAccessAnalyzer/Tests/AWSAccessAnalyzerTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAccessAnalyzer/Tests/AWSAccessAnalyzerTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAccessAnalyzer
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -850,7 +851,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -889,7 +890,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -967,7 +968,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAccount/Sources/AWSAccount/Endpoints.swift b/Sources/Services/AWSAccount/Sources/AWSAccount/Endpoints.swift
index 9b46a53c4ce..316d83143a6 100644
--- a/Sources/Services/AWSAccount/Sources/AWSAccount/Endpoints.swift
+++ b/Sources/Services/AWSAccount/Sources/AWSAccount/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAccount/Tests/AWSAccountTests/EndpointResolverTest.swift b/Sources/Services/AWSAccount/Tests/AWSAccountTests/EndpointResolverTest.swift
index 8de1dca2ca3..8b1ecf943ca 100644
--- a/Sources/Services/AWSAccount/Tests/AWSAccountTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAccount/Tests/AWSAccountTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAccount
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,14 +88,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -114,14 +115,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -141,14 +142,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -168,14 +169,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -195,14 +196,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -222,14 +223,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -249,14 +250,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -276,14 +277,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -303,14 +304,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -330,14 +331,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -357,14 +358,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -384,14 +385,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -430,14 +431,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -476,14 +477,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -522,14 +523,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,14 +569,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -614,14 +615,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -660,14 +661,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -706,14 +707,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -752,14 +753,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAmp/Sources/AWSAmp/Endpoints.swift b/Sources/Services/AWSAmp/Sources/AWSAmp/Endpoints.swift
index 75e8d0d00cb..136dde32d30 100644
--- a/Sources/Services/AWSAmp/Sources/AWSAmp/Endpoints.swift
+++ b/Sources/Services/AWSAmp/Sources/AWSAmp/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAmp/Tests/AWSAmpTests/EndpointResolverTest.swift b/Sources/Services/AWSAmp/Tests/AWSAmpTests/EndpointResolverTest.swift
index f9ebcb4e5ee..cc7198ec5fa 100644
--- a/Sources/Services/AWSAmp/Tests/AWSAmpTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAmp/Tests/AWSAmpTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAmp
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -470,7 +471,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -509,7 +510,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -587,7 +588,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -608,7 +609,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAmplify/Sources/AWSAmplify/Endpoints.swift b/Sources/Services/AWSAmplify/Sources/AWSAmplify/Endpoints.swift
index 305d8f1bd5a..a41639504f0 100644
--- a/Sources/Services/AWSAmplify/Sources/AWSAmplify/Endpoints.swift
+++ b/Sources/Services/AWSAmplify/Sources/AWSAmplify/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAmplify/Tests/AWSAmplifyTests/EndpointResolverTest.swift b/Sources/Services/AWSAmplify/Tests/AWSAmplifyTests/EndpointResolverTest.swift
index 464381da659..a402776cc43 100644
--- a/Sources/Services/AWSAmplify/Tests/AWSAmplifyTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAmplify/Tests/AWSAmplifyTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAmplify
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -650,7 +651,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -689,7 +690,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -767,7 +768,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -788,7 +789,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -808,7 +809,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAmplifyBackend/Sources/AWSAmplifyBackend/Endpoints.swift b/Sources/Services/AWSAmplifyBackend/Sources/AWSAmplifyBackend/Endpoints.swift
index f2cdbeebc49..93f465990d4 100644
--- a/Sources/Services/AWSAmplifyBackend/Sources/AWSAmplifyBackend/Endpoints.swift
+++ b/Sources/Services/AWSAmplifyBackend/Sources/AWSAmplifyBackend/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAmplifyBackend/Tests/AWSAmplifyBackendTests/EndpointResolverTest.swift b/Sources/Services/AWSAmplifyBackend/Tests/AWSAmplifyBackendTests/EndpointResolverTest.swift
index 7d528b0612e..cb950b7e408 100644
--- a/Sources/Services/AWSAmplifyBackend/Tests/AWSAmplifyBackendTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAmplifyBackend/Tests/AWSAmplifyBackendTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAmplifyBackend
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -610,7 +611,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -649,7 +650,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -688,7 +689,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -727,7 +728,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -768,7 +769,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAmplifyUIBuilder/Sources/AWSAmplifyUIBuilder/Endpoints.swift b/Sources/Services/AWSAmplifyUIBuilder/Sources/AWSAmplifyUIBuilder/Endpoints.swift
index 717841044c9..74fff17a809 100644
--- a/Sources/Services/AWSAmplifyUIBuilder/Sources/AWSAmplifyUIBuilder/Endpoints.swift
+++ b/Sources/Services/AWSAmplifyUIBuilder/Sources/AWSAmplifyUIBuilder/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAmplifyUIBuilder/Tests/AWSAmplifyUIBuilderTests/EndpointResolverTest.swift b/Sources/Services/AWSAmplifyUIBuilder/Tests/AWSAmplifyUIBuilderTests/EndpointResolverTest.swift
index 63a3e632b41..006ef95237e 100644
--- a/Sources/Services/AWSAmplifyUIBuilder/Tests/AWSAmplifyUIBuilderTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAmplifyUIBuilder/Tests/AWSAmplifyUIBuilderTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAmplifyUIBuilder
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -610,7 +611,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -649,7 +650,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -688,7 +689,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -727,7 +728,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -768,7 +769,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSApiGatewayManagementApi/Sources/AWSApiGatewayManagementApi/Endpoints.swift b/Sources/Services/AWSApiGatewayManagementApi/Sources/AWSApiGatewayManagementApi/Endpoints.swift
index c8b0b85e036..0ce690df732 100644
--- a/Sources/Services/AWSApiGatewayManagementApi/Sources/AWSApiGatewayManagementApi/Endpoints.swift
+++ b/Sources/Services/AWSApiGatewayManagementApi/Sources/AWSApiGatewayManagementApi/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSApiGatewayManagementApi/Tests/AWSApiGatewayManagementApiTests/EndpointResolverTest.swift b/Sources/Services/AWSApiGatewayManagementApi/Tests/AWSApiGatewayManagementApiTests/EndpointResolverTest.swift
index 6de8ce0a3a4..fac6bf4db1d 100644
--- a/Sources/Services/AWSApiGatewayManagementApi/Tests/AWSApiGatewayManagementApiTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSApiGatewayManagementApi/Tests/AWSApiGatewayManagementApiTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSApiGatewayManagementApi
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSApiGatewayV2/Sources/AWSApiGatewayV2/Endpoints.swift b/Sources/Services/AWSApiGatewayV2/Sources/AWSApiGatewayV2/Endpoints.swift
index bc4acae8293..eec28046038 100644
--- a/Sources/Services/AWSApiGatewayV2/Sources/AWSApiGatewayV2/Endpoints.swift
+++ b/Sources/Services/AWSApiGatewayV2/Sources/AWSApiGatewayV2/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSApiGatewayV2/Tests/AWSApiGatewayV2Tests/EndpointResolverTest.swift b/Sources/Services/AWSApiGatewayV2/Tests/AWSApiGatewayV2Tests/EndpointResolverTest.swift
index 8783a8a9022..ac5f31d3f8b 100644
--- a/Sources/Services/AWSApiGatewayV2/Tests/AWSApiGatewayV2Tests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSApiGatewayV2/Tests/AWSApiGatewayV2Tests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSApiGatewayV2
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -750,7 +751,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -808,7 +809,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -847,7 +848,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -868,7 +869,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAppConfig/Sources/AWSAppConfig/Endpoints.swift b/Sources/Services/AWSAppConfig/Sources/AWSAppConfig/Endpoints.swift
index a3b125f9875..614b61e9d5c 100644
--- a/Sources/Services/AWSAppConfig/Sources/AWSAppConfig/Endpoints.swift
+++ b/Sources/Services/AWSAppConfig/Sources/AWSAppConfig/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAppConfig/Tests/AWSAppConfigTests/EndpointResolverTest.swift b/Sources/Services/AWSAppConfig/Tests/AWSAppConfigTests/EndpointResolverTest.swift
index 89e63fdd008..538a4064e1c 100644
--- a/Sources/Services/AWSAppConfig/Tests/AWSAppConfigTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAppConfig/Tests/AWSAppConfigTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAppConfig
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -810,7 +811,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -849,7 +850,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAppConfigData/Sources/AWSAppConfigData/Endpoints.swift b/Sources/Services/AWSAppConfigData/Sources/AWSAppConfigData/Endpoints.swift
index 0c458191ce1..cdb7923ab23 100644
--- a/Sources/Services/AWSAppConfigData/Sources/AWSAppConfigData/Endpoints.swift
+++ b/Sources/Services/AWSAppConfigData/Sources/AWSAppConfigData/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAppConfigData/Tests/AWSAppConfigDataTests/EndpointResolverTest.swift b/Sources/Services/AWSAppConfigData/Tests/AWSAppConfigDataTests/EndpointResolverTest.swift
index 93895517ce5..1ad4489e65a 100644
--- a/Sources/Services/AWSAppConfigData/Tests/AWSAppConfigDataTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAppConfigData/Tests/AWSAppConfigDataTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAppConfigData
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -750,7 +751,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -789,7 +790,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -828,7 +829,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -867,7 +868,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAppFabric/Sources/AWSAppFabric/Endpoints.swift b/Sources/Services/AWSAppFabric/Sources/AWSAppFabric/Endpoints.swift
index 0675851ea31..922a2efe118 100644
--- a/Sources/Services/AWSAppFabric/Sources/AWSAppFabric/Endpoints.swift
+++ b/Sources/Services/AWSAppFabric/Sources/AWSAppFabric/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAppFabric/Tests/AWSAppFabricTests/EndpointResolverTest.swift b/Sources/Services/AWSAppFabric/Tests/AWSAppFabricTests/EndpointResolverTest.swift
index cf2ec8974c7..f8dde4a315d 100644
--- a/Sources/Services/AWSAppFabric/Tests/AWSAppFabricTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAppFabric/Tests/AWSAppFabricTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAppFabric
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAppIntegrations/Sources/AWSAppIntegrations/Endpoints.swift b/Sources/Services/AWSAppIntegrations/Sources/AWSAppIntegrations/Endpoints.swift
index 35be4d1a426..7a92a87fbc5 100644
--- a/Sources/Services/AWSAppIntegrations/Sources/AWSAppIntegrations/Endpoints.swift
+++ b/Sources/Services/AWSAppIntegrations/Sources/AWSAppIntegrations/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAppIntegrations/Tests/AWSAppIntegrationsTests/EndpointResolverTest.swift b/Sources/Services/AWSAppIntegrations/Tests/AWSAppIntegrationsTests/EndpointResolverTest.swift
index 09d4eaacc98..2acfce63515 100644
--- a/Sources/Services/AWSAppIntegrations/Tests/AWSAppIntegrationsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAppIntegrations/Tests/AWSAppIntegrationsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAppIntegrations
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -470,7 +471,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -509,7 +510,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -587,7 +588,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -608,7 +609,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAppMesh/Sources/AWSAppMesh/Endpoints.swift b/Sources/Services/AWSAppMesh/Sources/AWSAppMesh/Endpoints.swift
index fdc12f106af..372580ff09b 100644
--- a/Sources/Services/AWSAppMesh/Sources/AWSAppMesh/Endpoints.swift
+++ b/Sources/Services/AWSAppMesh/Sources/AWSAppMesh/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAppMesh/Tests/AWSAppMeshTests/EndpointResolverTest.swift b/Sources/Services/AWSAppMesh/Tests/AWSAppMeshTests/EndpointResolverTest.swift
index 80a8025d96e..d23be6f5bcb 100644
--- a/Sources/Services/AWSAppMesh/Tests/AWSAppMeshTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAppMesh/Tests/AWSAppMeshTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAppMesh
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -851,7 +852,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -871,7 +872,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -891,7 +892,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -911,7 +912,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -931,7 +932,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -951,7 +952,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -971,7 +972,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -991,7 +992,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1011,7 +1012,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1031,7 +1032,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1051,7 +1052,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1090,7 +1091,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1129,7 +1130,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1168,7 +1169,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1207,7 +1208,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1228,7 +1229,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1248,7 +1249,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAppRunner/Sources/AWSAppRunner/Endpoints.swift b/Sources/Services/AWSAppRunner/Sources/AWSAppRunner/Endpoints.swift
index 6d3eef60af5..328e372157e 100644
--- a/Sources/Services/AWSAppRunner/Sources/AWSAppRunner/Endpoints.swift
+++ b/Sources/Services/AWSAppRunner/Sources/AWSAppRunner/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAppRunner/Tests/AWSAppRunnerTests/EndpointResolverTest.swift b/Sources/Services/AWSAppRunner/Tests/AWSAppRunnerTests/EndpointResolverTest.swift
index 5ab1d68cf82..3584a6d5711 100644
--- a/Sources/Services/AWSAppRunner/Tests/AWSAppRunnerTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAppRunner/Tests/AWSAppRunnerTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAppRunner
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -410,7 +411,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -449,7 +450,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -527,7 +528,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAppStream/Sources/AWSAppStream/Endpoints.swift b/Sources/Services/AWSAppStream/Sources/AWSAppStream/Endpoints.swift
index 4ab8da7a16e..1eba4d5e801 100644
--- a/Sources/Services/AWSAppStream/Sources/AWSAppStream/Endpoints.swift
+++ b/Sources/Services/AWSAppStream/Sources/AWSAppStream/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAppStream/Tests/AWSAppStreamTests/EndpointResolverTest.swift b/Sources/Services/AWSAppStream/Tests/AWSAppStreamTests/EndpointResolverTest.swift
index f51d79735c1..92bbf4544c6 100644
--- a/Sources/Services/AWSAppStream/Tests/AWSAppStreamTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAppStream/Tests/AWSAppStreamTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAppStream
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -570,7 +571,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -609,7 +610,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -687,7 +688,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -708,7 +709,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAppSync/Sources/AWSAppSync/Endpoints.swift b/Sources/Services/AWSAppSync/Sources/AWSAppSync/Endpoints.swift
index 669d12280f4..c428bf49803 100644
--- a/Sources/Services/AWSAppSync/Sources/AWSAppSync/Endpoints.swift
+++ b/Sources/Services/AWSAppSync/Sources/AWSAppSync/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAppSync/Tests/AWSAppSyncTests/EndpointResolverTest.swift b/Sources/Services/AWSAppSync/Tests/AWSAppSyncTests/EndpointResolverTest.swift
index 606c1993043..61e2152c8e8 100644
--- a/Sources/Services/AWSAppSync/Tests/AWSAppSyncTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAppSync/Tests/AWSAppSyncTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAppSync
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -690,7 +691,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -729,7 +730,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -768,7 +769,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -807,7 +808,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -828,7 +829,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAppTest/Sources/AWSAppTest/Endpoints.swift b/Sources/Services/AWSAppTest/Sources/AWSAppTest/Endpoints.swift
index 8e36940bf51..08acad39401 100644
--- a/Sources/Services/AWSAppTest/Sources/AWSAppTest/Endpoints.swift
+++ b/Sources/Services/AWSAppTest/Sources/AWSAppTest/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAppTest/Tests/AWSAppTestTests/EndpointResolverTest.swift b/Sources/Services/AWSAppTest/Tests/AWSAppTestTests/EndpointResolverTest.swift
index f19a32271a9..31dd67c1867 100644
--- a/Sources/Services/AWSAppTest/Tests/AWSAppTestTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAppTest/Tests/AWSAppTestTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAppTest
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAppflow/Sources/AWSAppflow/Endpoints.swift b/Sources/Services/AWSAppflow/Sources/AWSAppflow/Endpoints.swift
index 8643e3c14d4..ce2e48def70 100644
--- a/Sources/Services/AWSAppflow/Sources/AWSAppflow/Endpoints.swift
+++ b/Sources/Services/AWSAppflow/Sources/AWSAppflow/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAppflow/Tests/AWSAppflowTests/EndpointResolverTest.swift b/Sources/Services/AWSAppflow/Tests/AWSAppflowTests/EndpointResolverTest.swift
index 3994afbe4a1..4b498fa859a 100644
--- a/Sources/Services/AWSAppflow/Tests/AWSAppflowTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAppflow/Tests/AWSAppflowTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAppflow
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -590,7 +591,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -629,7 +630,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -707,7 +708,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSApplicationAutoScaling/Sources/AWSApplicationAutoScaling/Endpoints.swift b/Sources/Services/AWSApplicationAutoScaling/Sources/AWSApplicationAutoScaling/Endpoints.swift
index 7dcf648953c..f8e9a24adbe 100644
--- a/Sources/Services/AWSApplicationAutoScaling/Sources/AWSApplicationAutoScaling/Endpoints.swift
+++ b/Sources/Services/AWSApplicationAutoScaling/Sources/AWSApplicationAutoScaling/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSApplicationAutoScaling/Tests/AWSApplicationAutoScalingTests/EndpointResolverTest.swift b/Sources/Services/AWSApplicationAutoScaling/Tests/AWSApplicationAutoScalingTests/EndpointResolverTest.swift
index 33de66c9bd5..cee67400fe9 100644
--- a/Sources/Services/AWSApplicationAutoScaling/Tests/AWSApplicationAutoScalingTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSApplicationAutoScaling/Tests/AWSApplicationAutoScalingTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSApplicationAutoScaling
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -810,7 +811,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -849,7 +850,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSApplicationCostProfiler/Sources/AWSApplicationCostProfiler/Endpoints.swift b/Sources/Services/AWSApplicationCostProfiler/Sources/AWSApplicationCostProfiler/Endpoints.swift
index 28e5f4cbd02..6e4ad109390 100644
--- a/Sources/Services/AWSApplicationCostProfiler/Sources/AWSApplicationCostProfiler/Endpoints.swift
+++ b/Sources/Services/AWSApplicationCostProfiler/Sources/AWSApplicationCostProfiler/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSApplicationCostProfiler/Tests/AWSApplicationCostProfilerTests/EndpointResolverTest.swift b/Sources/Services/AWSApplicationCostProfiler/Tests/AWSApplicationCostProfilerTests/EndpointResolverTest.swift
index 00e7df85ee1..d69eff1dfb7 100644
--- a/Sources/Services/AWSApplicationCostProfiler/Tests/AWSApplicationCostProfilerTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSApplicationCostProfiler/Tests/AWSApplicationCostProfilerTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSApplicationCostProfiler
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSApplicationDiscoveryService/Sources/AWSApplicationDiscoveryService/Endpoints.swift b/Sources/Services/AWSApplicationDiscoveryService/Sources/AWSApplicationDiscoveryService/Endpoints.swift
index 2b575359242..6c610cd64f8 100644
--- a/Sources/Services/AWSApplicationDiscoveryService/Sources/AWSApplicationDiscoveryService/Endpoints.swift
+++ b/Sources/Services/AWSApplicationDiscoveryService/Sources/AWSApplicationDiscoveryService/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSApplicationDiscoveryService/Tests/AWSApplicationDiscoveryServiceTests/EndpointResolverTest.swift b/Sources/Services/AWSApplicationDiscoveryService/Tests/AWSApplicationDiscoveryServiceTests/EndpointResolverTest.swift
index 558e61b688d..0a1b571d2c4 100644
--- a/Sources/Services/AWSApplicationDiscoveryService/Tests/AWSApplicationDiscoveryServiceTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSApplicationDiscoveryService/Tests/AWSApplicationDiscoveryServiceTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSApplicationDiscoveryService
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -410,7 +411,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -449,7 +450,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -527,7 +528,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSApplicationInsights/Sources/AWSApplicationInsights/Endpoints.swift b/Sources/Services/AWSApplicationInsights/Sources/AWSApplicationInsights/Endpoints.swift
index b0a931f7f6d..d4f638f18cd 100644
--- a/Sources/Services/AWSApplicationInsights/Sources/AWSApplicationInsights/Endpoints.swift
+++ b/Sources/Services/AWSApplicationInsights/Sources/AWSApplicationInsights/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSApplicationInsights/Tests/AWSApplicationInsightsTests/EndpointResolverTest.swift b/Sources/Services/AWSApplicationInsights/Tests/AWSApplicationInsightsTests/EndpointResolverTest.swift
index 72aa678b20c..a983db1e064 100644
--- a/Sources/Services/AWSApplicationInsights/Tests/AWSApplicationInsightsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSApplicationInsights/Tests/AWSApplicationInsightsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSApplicationInsights
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -730,7 +731,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -769,7 +770,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -808,7 +809,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -847,7 +848,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -868,7 +869,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSApplicationSignals/Sources/AWSApplicationSignals/Endpoints.swift b/Sources/Services/AWSApplicationSignals/Sources/AWSApplicationSignals/Endpoints.swift
index 16cdfaae928..07302f58930 100644
--- a/Sources/Services/AWSApplicationSignals/Sources/AWSApplicationSignals/Endpoints.swift
+++ b/Sources/Services/AWSApplicationSignals/Sources/AWSApplicationSignals/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSApplicationSignals/Tests/AWSApplicationSignalsTests/EndpointResolverTest.swift b/Sources/Services/AWSApplicationSignals/Tests/AWSApplicationSignalsTests/EndpointResolverTest.swift
index 73c502eae1e..1987c0147e5 100644
--- a/Sources/Services/AWSApplicationSignals/Tests/AWSApplicationSignalsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSApplicationSignals/Tests/AWSApplicationSignalsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSApplicationSignals
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -67,7 +68,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -86,7 +87,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -105,7 +106,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -124,7 +125,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -143,7 +144,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -162,7 +163,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -181,7 +182,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -200,7 +201,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -219,7 +220,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -238,7 +239,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -257,7 +258,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -276,7 +277,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -295,7 +296,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -314,7 +315,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSArtifact/Sources/AWSArtifact/Endpoints.swift b/Sources/Services/AWSArtifact/Sources/AWSArtifact/Endpoints.swift
index 4199e2a5cef..d61704c0fda 100644
--- a/Sources/Services/AWSArtifact/Sources/AWSArtifact/Endpoints.swift
+++ b/Sources/Services/AWSArtifact/Sources/AWSArtifact/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSArtifact/Tests/AWSArtifactTests/EndpointResolverTest.swift b/Sources/Services/AWSArtifact/Tests/AWSArtifactTests/EndpointResolverTest.swift
index 073ab550bac..eb6013e47ae 100644
--- a/Sources/Services/AWSArtifact/Tests/AWSArtifactTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSArtifact/Tests/AWSArtifactTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSArtifact
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,14 +88,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -114,14 +115,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -141,14 +142,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -168,14 +169,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -195,14 +196,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -222,14 +223,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -249,14 +250,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -276,14 +277,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -303,14 +304,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -330,14 +331,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -357,14 +358,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -384,14 +385,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -430,14 +431,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -476,14 +477,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -522,14 +523,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,14 +569,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -614,14 +615,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -660,14 +661,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -706,14 +707,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -752,14 +753,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAthena/Sources/AWSAthena/Endpoints.swift b/Sources/Services/AWSAthena/Sources/AWSAthena/Endpoints.swift
index d21e5ccf4c2..72a53d80264 100644
--- a/Sources/Services/AWSAthena/Sources/AWSAthena/Endpoints.swift
+++ b/Sources/Services/AWSAthena/Sources/AWSAthena/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAthena/Tests/AWSAthenaTests/EndpointResolverTest.swift b/Sources/Services/AWSAthena/Tests/AWSAthenaTests/EndpointResolverTest.swift
index 4fdc4f31983..170d66032a8 100644
--- a/Sources/Services/AWSAthena/Tests/AWSAthenaTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAthena/Tests/AWSAthenaTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAthena
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -810,7 +811,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -849,7 +850,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -927,7 +928,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAuditManager/Sources/AWSAuditManager/Endpoints.swift b/Sources/Services/AWSAuditManager/Sources/AWSAuditManager/Endpoints.swift
index b290cc92f84..f3b90cb4ce0 100644
--- a/Sources/Services/AWSAuditManager/Sources/AWSAuditManager/Endpoints.swift
+++ b/Sources/Services/AWSAuditManager/Sources/AWSAuditManager/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAuditManager/Tests/AWSAuditManagerTests/EndpointResolverTest.swift b/Sources/Services/AWSAuditManager/Tests/AWSAuditManagerTests/EndpointResolverTest.swift
index fbba60e06ee..d5cecf773fb 100644
--- a/Sources/Services/AWSAuditManager/Tests/AWSAuditManagerTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAuditManager/Tests/AWSAuditManagerTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAuditManager
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -510,7 +511,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -549,7 +550,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -588,7 +589,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -627,7 +628,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAutoScaling/Sources/AWSAutoScaling/Endpoints.swift b/Sources/Services/AWSAutoScaling/Sources/AWSAutoScaling/Endpoints.swift
index a683c801bed..70f88865ee4 100644
--- a/Sources/Services/AWSAutoScaling/Sources/AWSAutoScaling/Endpoints.swift
+++ b/Sources/Services/AWSAutoScaling/Sources/AWSAutoScaling/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAutoScaling/Tests/AWSAutoScalingTests/EndpointResolverTest.swift b/Sources/Services/AWSAutoScaling/Tests/AWSAutoScalingTests/EndpointResolverTest.swift
index a909683f452..414cb3e857a 100644
--- a/Sources/Services/AWSAutoScaling/Tests/AWSAutoScalingTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAutoScaling/Tests/AWSAutoScalingTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAutoScaling
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -790,7 +791,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -829,7 +830,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -868,7 +869,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSAutoScalingPlans/Sources/AWSAutoScalingPlans/Endpoints.swift b/Sources/Services/AWSAutoScalingPlans/Sources/AWSAutoScalingPlans/Endpoints.swift
index 7a7458cc3bc..ff29c138a56 100644
--- a/Sources/Services/AWSAutoScalingPlans/Sources/AWSAutoScalingPlans/Endpoints.swift
+++ b/Sources/Services/AWSAutoScalingPlans/Sources/AWSAutoScalingPlans/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSAutoScalingPlans/Tests/AWSAutoScalingPlansTests/EndpointResolverTest.swift b/Sources/Services/AWSAutoScalingPlans/Tests/AWSAutoScalingPlansTests/EndpointResolverTest.swift
index 02ce2ce6d24..ea75fd8e3b8 100644
--- a/Sources/Services/AWSAutoScalingPlans/Tests/AWSAutoScalingPlansTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSAutoScalingPlans/Tests/AWSAutoScalingPlansTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSAutoScalingPlans
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -750,7 +751,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -789,7 +790,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -828,7 +829,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -867,7 +868,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSB2bi/Sources/AWSB2bi/Endpoints.swift b/Sources/Services/AWSB2bi/Sources/AWSB2bi/Endpoints.swift
index 1c8f84cf3a3..1129c1e58b4 100644
--- a/Sources/Services/AWSB2bi/Sources/AWSB2bi/Endpoints.swift
+++ b/Sources/Services/AWSB2bi/Sources/AWSB2bi/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSB2bi/Tests/AWSB2biTests/EndpointResolverTest.swift b/Sources/Services/AWSB2bi/Tests/AWSB2biTests/EndpointResolverTest.swift
index 6da4ba1b67b..d94e47b4082 100644
--- a/Sources/Services/AWSB2bi/Tests/AWSB2biTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSB2bi/Tests/AWSB2biTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSB2bi
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSBCMDataExports/Sources/AWSBCMDataExports/Endpoints.swift b/Sources/Services/AWSBCMDataExports/Sources/AWSBCMDataExports/Endpoints.swift
index d594a6226d7..1aa7075fae9 100644
--- a/Sources/Services/AWSBCMDataExports/Sources/AWSBCMDataExports/Endpoints.swift
+++ b/Sources/Services/AWSBCMDataExports/Sources/AWSBCMDataExports/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSBCMDataExports/Tests/AWSBCMDataExportsTests/EndpointResolverTest.swift b/Sources/Services/AWSBCMDataExports/Tests/AWSBCMDataExportsTests/EndpointResolverTest.swift
index 79c6a7abaee..6796f9ee36a 100644
--- a/Sources/Services/AWSBCMDataExports/Tests/AWSBCMDataExportsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSBCMDataExports/Tests/AWSBCMDataExportsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSBCMDataExports
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,15 +31,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "bcm-data-exports",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -57,7 +58,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -76,15 +77,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "bcm-data-exports",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -103,7 +104,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -122,7 +123,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -141,7 +142,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -160,7 +161,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -180,7 +181,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -199,7 +200,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSBCMPricingCalculator/Sources/AWSBCMPricingCalculator/Endpoints.swift b/Sources/Services/AWSBCMPricingCalculator/Sources/AWSBCMPricingCalculator/Endpoints.swift
index cff43257202..28c0b558cdc 100644
--- a/Sources/Services/AWSBCMPricingCalculator/Sources/AWSBCMPricingCalculator/Endpoints.swift
+++ b/Sources/Services/AWSBCMPricingCalculator/Sources/AWSBCMPricingCalculator/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSBCMPricingCalculator/Tests/AWSBCMPricingCalculatorTests/EndpointResolverTest.swift b/Sources/Services/AWSBCMPricingCalculator/Tests/AWSBCMPricingCalculatorTests/EndpointResolverTest.swift
index 3b31649dc9e..4fc85e4693f 100644
--- a/Sources/Services/AWSBCMPricingCalculator/Tests/AWSBCMPricingCalculatorTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSBCMPricingCalculator/Tests/AWSBCMPricingCalculatorTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSBCMPricingCalculator
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -67,14 +68,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -93,14 +94,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -119,14 +120,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -145,14 +146,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,14 +172,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -197,14 +198,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -223,14 +224,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -249,14 +250,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -275,14 +276,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -301,14 +302,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -327,14 +328,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -353,14 +354,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -379,14 +380,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -405,14 +406,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSBackup/Sources/AWSBackup/Endpoints.swift b/Sources/Services/AWSBackup/Sources/AWSBackup/Endpoints.swift
index e86a9eda855..ac3e662ab8a 100644
--- a/Sources/Services/AWSBackup/Sources/AWSBackup/Endpoints.swift
+++ b/Sources/Services/AWSBackup/Sources/AWSBackup/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSBackup/Tests/AWSBackupTests/EndpointResolverTest.swift b/Sources/Services/AWSBackup/Tests/AWSBackupTests/EndpointResolverTest.swift
index 73bc1bcc464..6cfce79520c 100644
--- a/Sources/Services/AWSBackup/Tests/AWSBackupTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSBackup/Tests/AWSBackupTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSBackup
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -750,7 +751,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -789,7 +790,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -828,7 +829,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -867,7 +868,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSBackupGateway/Sources/AWSBackupGateway/Endpoints.swift b/Sources/Services/AWSBackupGateway/Sources/AWSBackupGateway/Endpoints.swift
index 96516b3eed3..bb419091617 100644
--- a/Sources/Services/AWSBackupGateway/Sources/AWSBackupGateway/Endpoints.swift
+++ b/Sources/Services/AWSBackupGateway/Sources/AWSBackupGateway/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSBackupGateway/Tests/AWSBackupGatewayTests/EndpointResolverTest.swift b/Sources/Services/AWSBackupGateway/Tests/AWSBackupGatewayTests/EndpointResolverTest.swift
index 0fc58e66fcf..5c9cbeeb664 100644
--- a/Sources/Services/AWSBackupGateway/Tests/AWSBackupGatewayTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSBackupGateway/Tests/AWSBackupGatewayTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSBackupGateway
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -710,7 +711,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -749,7 +750,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -788,7 +789,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -827,7 +828,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -868,7 +869,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSBackupSearch/Sources/AWSBackupSearch/Endpoints.swift b/Sources/Services/AWSBackupSearch/Sources/AWSBackupSearch/Endpoints.swift
index 574f72434ec..7f8abf30adf 100644
--- a/Sources/Services/AWSBackupSearch/Sources/AWSBackupSearch/Endpoints.swift
+++ b/Sources/Services/AWSBackupSearch/Sources/AWSBackupSearch/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSBackupSearch/Tests/AWSBackupSearchTests/EndpointResolverTest.swift b/Sources/Services/AWSBackupSearch/Tests/AWSBackupSearchTests/EndpointResolverTest.swift
index 561e22753bf..e4ea0a8ed2d 100644
--- a/Sources/Services/AWSBackupSearch/Tests/AWSBackupSearchTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSBackupSearch/Tests/AWSBackupSearchTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSBackupSearch
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -67,14 +68,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -93,14 +94,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -119,14 +120,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -145,14 +146,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,14 +172,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -197,14 +198,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -223,14 +224,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -249,14 +250,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -275,14 +276,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -301,14 +302,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -327,14 +328,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -353,14 +354,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -379,14 +380,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -405,14 +406,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSBatch/Sources/AWSBatch/Endpoints.swift b/Sources/Services/AWSBatch/Sources/AWSBatch/Endpoints.swift
index 958c1f4f3f9..3995a12778d 100644
--- a/Sources/Services/AWSBatch/Sources/AWSBatch/Endpoints.swift
+++ b/Sources/Services/AWSBatch/Sources/AWSBatch/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSBatch/Tests/AWSBatchTests/EndpointResolverTest.swift b/Sources/Services/AWSBatch/Tests/AWSBatchTests/EndpointResolverTest.swift
index 168e969c395..b5bc90aae20 100644
--- a/Sources/Services/AWSBatch/Tests/AWSBatchTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSBatch/Tests/AWSBatchTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSBatch
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -830,7 +831,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -869,7 +870,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -947,7 +948,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSBedrock/Sources/AWSBedrock/Endpoints.swift b/Sources/Services/AWSBedrock/Sources/AWSBedrock/Endpoints.swift
index d6bf8fd5dc7..50a0e7f8f79 100644
--- a/Sources/Services/AWSBedrock/Sources/AWSBedrock/Endpoints.swift
+++ b/Sources/Services/AWSBedrock/Sources/AWSBedrock/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSBedrock/Tests/AWSBedrockTests/EndpointResolverTest.swift b/Sources/Services/AWSBedrock/Tests/AWSBedrockTests/EndpointResolverTest.swift
index d87ff822837..1f2bbaa82ab 100644
--- a/Sources/Services/AWSBedrock/Tests/AWSBedrockTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSBedrock/Tests/AWSBedrockTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSBedrock
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSBedrockAgent/Sources/AWSBedrockAgent/Endpoints.swift b/Sources/Services/AWSBedrockAgent/Sources/AWSBedrockAgent/Endpoints.swift
index 69ab84a5137..ed3b182bd03 100644
--- a/Sources/Services/AWSBedrockAgent/Sources/AWSBedrockAgent/Endpoints.swift
+++ b/Sources/Services/AWSBedrockAgent/Sources/AWSBedrockAgent/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSBedrockAgent/Tests/AWSBedrockAgentTests/EndpointResolverTest.swift b/Sources/Services/AWSBedrockAgent/Tests/AWSBedrockAgentTests/EndpointResolverTest.swift
index 379163f364d..ec04f1b0326 100644
--- a/Sources/Services/AWSBedrockAgent/Tests/AWSBedrockAgentTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSBedrockAgent/Tests/AWSBedrockAgentTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSBedrockAgent
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSBedrockAgentRuntime/Sources/AWSBedrockAgentRuntime/Endpoints.swift b/Sources/Services/AWSBedrockAgentRuntime/Sources/AWSBedrockAgentRuntime/Endpoints.swift
index eb812870f6b..374e0c24ac4 100644
--- a/Sources/Services/AWSBedrockAgentRuntime/Sources/AWSBedrockAgentRuntime/Endpoints.swift
+++ b/Sources/Services/AWSBedrockAgentRuntime/Sources/AWSBedrockAgentRuntime/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSBedrockAgentRuntime/Tests/AWSBedrockAgentRuntimeTests/EndpointResolverTest.swift b/Sources/Services/AWSBedrockAgentRuntime/Tests/AWSBedrockAgentRuntimeTests/EndpointResolverTest.swift
index 4a351f090af..fe540a4db9e 100644
--- a/Sources/Services/AWSBedrockAgentRuntime/Tests/AWSBedrockAgentRuntimeTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSBedrockAgentRuntime/Tests/AWSBedrockAgentRuntimeTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSBedrockAgentRuntime
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSBedrockDataAutomation/Sources/AWSBedrockDataAutomation/Endpoints.swift b/Sources/Services/AWSBedrockDataAutomation/Sources/AWSBedrockDataAutomation/Endpoints.swift
index 45090884cdf..02dd9f371af 100644
--- a/Sources/Services/AWSBedrockDataAutomation/Sources/AWSBedrockDataAutomation/Endpoints.swift
+++ b/Sources/Services/AWSBedrockDataAutomation/Sources/AWSBedrockDataAutomation/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSBedrockDataAutomation/Tests/AWSBedrockDataAutomationTests/EndpointResolverTest.swift b/Sources/Services/AWSBedrockDataAutomation/Tests/AWSBedrockDataAutomationTests/EndpointResolverTest.swift
index 2ac71dc5d4b..74ab0feeec1 100644
--- a/Sources/Services/AWSBedrockDataAutomation/Tests/AWSBedrockDataAutomationTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSBedrockDataAutomation/Tests/AWSBedrockDataAutomationTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSBedrockDataAutomation
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSBedrockDataAutomationRuntime/Sources/AWSBedrockDataAutomationRuntime/Endpoints.swift b/Sources/Services/AWSBedrockDataAutomationRuntime/Sources/AWSBedrockDataAutomationRuntime/Endpoints.swift
index 71dd08e7acb..c43da0171d4 100644
--- a/Sources/Services/AWSBedrockDataAutomationRuntime/Sources/AWSBedrockDataAutomationRuntime/Endpoints.swift
+++ b/Sources/Services/AWSBedrockDataAutomationRuntime/Sources/AWSBedrockDataAutomationRuntime/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSBedrockDataAutomationRuntime/Tests/AWSBedrockDataAutomationRuntimeTests/EndpointResolverTest.swift b/Sources/Services/AWSBedrockDataAutomationRuntime/Tests/AWSBedrockDataAutomationRuntimeTests/EndpointResolverTest.swift
index 62976865d56..8732d743546 100644
--- a/Sources/Services/AWSBedrockDataAutomationRuntime/Tests/AWSBedrockDataAutomationRuntimeTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSBedrockDataAutomationRuntime/Tests/AWSBedrockDataAutomationRuntimeTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSBedrockDataAutomationRuntime
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSBedrockRuntime/Sources/AWSBedrockRuntime/Endpoints.swift b/Sources/Services/AWSBedrockRuntime/Sources/AWSBedrockRuntime/Endpoints.swift
index 50381c0f0ce..cf18842bb30 100644
--- a/Sources/Services/AWSBedrockRuntime/Sources/AWSBedrockRuntime/Endpoints.swift
+++ b/Sources/Services/AWSBedrockRuntime/Sources/AWSBedrockRuntime/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSBedrockRuntime/Tests/AWSBedrockRuntimeTests/EndpointResolverTest.swift b/Sources/Services/AWSBedrockRuntime/Tests/AWSBedrockRuntimeTests/EndpointResolverTest.swift
index 0fd238c94dd..baf90847e5e 100644
--- a/Sources/Services/AWSBedrockRuntime/Tests/AWSBedrockRuntimeTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSBedrockRuntime/Tests/AWSBedrockRuntimeTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSBedrockRuntime
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSBilling/Sources/AWSBilling/Endpoints.swift b/Sources/Services/AWSBilling/Sources/AWSBilling/Endpoints.swift
index c278f6dc27d..a86a1a3efc9 100644
--- a/Sources/Services/AWSBilling/Sources/AWSBilling/Endpoints.swift
+++ b/Sources/Services/AWSBilling/Sources/AWSBilling/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSBilling/Tests/AWSBillingTests/EndpointResolverTest.swift b/Sources/Services/AWSBilling/Tests/AWSBillingTests/EndpointResolverTest.swift
index b10f207f019..bd026a713a3 100644
--- a/Sources/Services/AWSBilling/Tests/AWSBillingTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSBilling/Tests/AWSBillingTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSBilling
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -67,14 +68,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -93,14 +94,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -119,14 +120,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -145,14 +146,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,14 +172,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -197,14 +198,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -223,14 +224,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -249,14 +250,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -275,14 +276,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -301,14 +302,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -327,14 +328,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -353,14 +354,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -379,14 +380,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -405,14 +406,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSBillingconductor/Sources/AWSBillingconductor/Endpoints.swift b/Sources/Services/AWSBillingconductor/Sources/AWSBillingconductor/Endpoints.swift
index d6864b801df..87ec4e39ca3 100644
--- a/Sources/Services/AWSBillingconductor/Sources/AWSBillingconductor/Endpoints.swift
+++ b/Sources/Services/AWSBillingconductor/Sources/AWSBillingconductor/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSBillingconductor/Tests/AWSBillingconductorTests/EndpointResolverTest.swift b/Sources/Services/AWSBillingconductor/Tests/AWSBillingconductorTests/EndpointResolverTest.swift
index 4f1e1db5829..8c9795099ef 100644
--- a/Sources/Services/AWSBillingconductor/Tests/AWSBillingconductorTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSBillingconductor/Tests/AWSBillingconductorTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSBillingconductor
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,15 +32,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "billingconductor",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -59,7 +60,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -79,7 +80,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -99,7 +100,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -119,15 +120,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "billingconductor",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -147,7 +148,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -167,7 +168,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -187,7 +188,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -207,7 +208,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -227,7 +228,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -247,7 +248,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -267,7 +268,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -287,7 +288,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -326,7 +327,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -365,7 +366,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -404,7 +405,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -443,7 +444,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -464,7 +465,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -484,7 +485,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSBraket/Sources/AWSBraket/Endpoints.swift b/Sources/Services/AWSBraket/Sources/AWSBraket/Endpoints.swift
index a41736363d7..365ee994ec8 100644
--- a/Sources/Services/AWSBraket/Sources/AWSBraket/Endpoints.swift
+++ b/Sources/Services/AWSBraket/Sources/AWSBraket/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSBraket/Tests/AWSBraketTests/EndpointResolverTest.swift b/Sources/Services/AWSBraket/Tests/AWSBraketTests/EndpointResolverTest.swift
index 44dafc0dd9a..ec90bb47439 100644
--- a/Sources/Services/AWSBraket/Tests/AWSBraketTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSBraket/Tests/AWSBraketTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSBraket
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -350,7 +351,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -389,7 +390,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -467,7 +468,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -508,7 +509,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSBudgets/Sources/AWSBudgets/Endpoints.swift b/Sources/Services/AWSBudgets/Sources/AWSBudgets/Endpoints.swift
index 1c770239a3f..fba09727f81 100644
--- a/Sources/Services/AWSBudgets/Sources/AWSBudgets/Endpoints.swift
+++ b/Sources/Services/AWSBudgets/Sources/AWSBudgets/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSBudgets/Tests/AWSBudgetsTests/EndpointResolverTest.swift b/Sources/Services/AWSBudgets/Tests/AWSBudgetsTests/EndpointResolverTest.swift
index fa8a07c446a..de19cc77721 100644
--- a/Sources/Services/AWSBudgets/Tests/AWSBudgetsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSBudgets/Tests/AWSBudgetsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSBudgets
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,15 +32,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "budgets",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -59,7 +60,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -79,7 +80,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -99,7 +100,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -119,15 +120,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "budgets",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -147,15 +148,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "budgets",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -175,7 +176,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -195,7 +196,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -215,7 +216,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -235,15 +236,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "budgets",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -263,7 +264,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -283,7 +284,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -303,7 +304,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -323,7 +324,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -343,15 +344,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "budgets",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -390,7 +391,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -429,15 +430,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "budgets",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -457,15 +458,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "budgets",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -504,7 +505,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -543,15 +544,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "budgets",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,15 +572,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "budgets",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -599,15 +600,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "budgets",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSChatbot/Sources/AWSChatbot/Endpoints.swift b/Sources/Services/AWSChatbot/Sources/AWSChatbot/Endpoints.swift
index 69336c8eef0..b0629031973 100644
--- a/Sources/Services/AWSChatbot/Sources/AWSChatbot/Endpoints.swift
+++ b/Sources/Services/AWSChatbot/Sources/AWSChatbot/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSChatbot/Tests/AWSChatbotTests/EndpointResolverTest.swift b/Sources/Services/AWSChatbot/Tests/AWSChatbotTests/EndpointResolverTest.swift
index cf9fefdfb85..cae3324c4e5 100644
--- a/Sources/Services/AWSChatbot/Tests/AWSChatbotTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSChatbot/Tests/AWSChatbotTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSChatbot
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSChime/Sources/AWSChime/Endpoints.swift b/Sources/Services/AWSChime/Sources/AWSChime/Endpoints.swift
index d2ffb002759..db2a5d3a544 100644
--- a/Sources/Services/AWSChime/Sources/AWSChime/Endpoints.swift
+++ b/Sources/Services/AWSChime/Sources/AWSChime/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSChime/Tests/AWSChimeTests/EndpointResolverTest.swift b/Sources/Services/AWSChime/Tests/AWSChimeTests/EndpointResolverTest.swift
index 22c6b3f4d9f..bcfd403a762 100644
--- a/Sources/Services/AWSChime/Tests/AWSChimeTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSChime/Tests/AWSChimeTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSChime
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,15 +32,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "chime",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -59,7 +60,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -79,7 +80,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -99,7 +100,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -119,15 +120,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "chime",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -147,7 +148,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -167,7 +168,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -187,7 +188,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -207,7 +208,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -227,7 +228,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -247,7 +248,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -267,7 +268,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -287,7 +288,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -326,7 +327,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -365,7 +366,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -404,7 +405,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -443,7 +444,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -464,7 +465,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -484,7 +485,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSChimeSDKIdentity/Sources/AWSChimeSDKIdentity/Endpoints.swift b/Sources/Services/AWSChimeSDKIdentity/Sources/AWSChimeSDKIdentity/Endpoints.swift
index 823db7d6887..82b6ff115db 100644
--- a/Sources/Services/AWSChimeSDKIdentity/Sources/AWSChimeSDKIdentity/Endpoints.swift
+++ b/Sources/Services/AWSChimeSDKIdentity/Sources/AWSChimeSDKIdentity/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSChimeSDKIdentity/Tests/AWSChimeSDKIdentityTests/EndpointResolverTest.swift b/Sources/Services/AWSChimeSDKIdentity/Tests/AWSChimeSDKIdentityTests/EndpointResolverTest.swift
index 9641bf63146..4f2b28a6e2e 100644
--- a/Sources/Services/AWSChimeSDKIdentity/Tests/AWSChimeSDKIdentityTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSChimeSDKIdentity/Tests/AWSChimeSDKIdentityTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSChimeSDKIdentity
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -310,7 +311,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -349,7 +350,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -388,7 +389,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -427,7 +428,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSChimeSDKMediaPipelines/Sources/AWSChimeSDKMediaPipelines/Endpoints.swift b/Sources/Services/AWSChimeSDKMediaPipelines/Sources/AWSChimeSDKMediaPipelines/Endpoints.swift
index 05aab43bc32..c274edcfa1c 100644
--- a/Sources/Services/AWSChimeSDKMediaPipelines/Sources/AWSChimeSDKMediaPipelines/Endpoints.swift
+++ b/Sources/Services/AWSChimeSDKMediaPipelines/Sources/AWSChimeSDKMediaPipelines/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSChimeSDKMediaPipelines/Tests/AWSChimeSDKMediaPipelinesTests/EndpointResolverTest.swift b/Sources/Services/AWSChimeSDKMediaPipelines/Tests/AWSChimeSDKMediaPipelinesTests/EndpointResolverTest.swift
index f8f45e0fe2f..686899e2e34 100644
--- a/Sources/Services/AWSChimeSDKMediaPipelines/Tests/AWSChimeSDKMediaPipelinesTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSChimeSDKMediaPipelines/Tests/AWSChimeSDKMediaPipelinesTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSChimeSDKMediaPipelines
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -370,7 +371,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -409,7 +410,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -487,7 +488,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -508,7 +509,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -528,7 +529,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSChimeSDKMeetings/Sources/AWSChimeSDKMeetings/Endpoints.swift b/Sources/Services/AWSChimeSDKMeetings/Sources/AWSChimeSDKMeetings/Endpoints.swift
index ea32c4592c5..c41221587a0 100644
--- a/Sources/Services/AWSChimeSDKMeetings/Sources/AWSChimeSDKMeetings/Endpoints.swift
+++ b/Sources/Services/AWSChimeSDKMeetings/Sources/AWSChimeSDKMeetings/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSChimeSDKMeetings/Tests/AWSChimeSDKMeetingsTests/EndpointResolverTest.swift b/Sources/Services/AWSChimeSDKMeetings/Tests/AWSChimeSDKMeetingsTests/EndpointResolverTest.swift
index 9a2fd1ca1b2..be27d955f07 100644
--- a/Sources/Services/AWSChimeSDKMeetings/Tests/AWSChimeSDKMeetingsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSChimeSDKMeetings/Tests/AWSChimeSDKMeetingsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSChimeSDKMeetings
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -410,7 +411,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -449,7 +450,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -527,7 +528,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSChimeSDKMessaging/Sources/AWSChimeSDKMessaging/Endpoints.swift b/Sources/Services/AWSChimeSDKMessaging/Sources/AWSChimeSDKMessaging/Endpoints.swift
index 85f1465c847..39c46de847d 100644
--- a/Sources/Services/AWSChimeSDKMessaging/Sources/AWSChimeSDKMessaging/Endpoints.swift
+++ b/Sources/Services/AWSChimeSDKMessaging/Sources/AWSChimeSDKMessaging/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSChimeSDKMessaging/Tests/AWSChimeSDKMessagingTests/EndpointResolverTest.swift b/Sources/Services/AWSChimeSDKMessaging/Tests/AWSChimeSDKMessagingTests/EndpointResolverTest.swift
index dcff21de5a5..621ce0bdda8 100644
--- a/Sources/Services/AWSChimeSDKMessaging/Tests/AWSChimeSDKMessagingTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSChimeSDKMessaging/Tests/AWSChimeSDKMessagingTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSChimeSDKMessaging
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -310,7 +311,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -349,7 +350,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -388,7 +389,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -427,7 +428,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSChimeSDKVoice/Sources/AWSChimeSDKVoice/Endpoints.swift b/Sources/Services/AWSChimeSDKVoice/Sources/AWSChimeSDKVoice/Endpoints.swift
index ff94a189001..d9add6b2444 100644
--- a/Sources/Services/AWSChimeSDKVoice/Sources/AWSChimeSDKVoice/Endpoints.swift
+++ b/Sources/Services/AWSChimeSDKVoice/Sources/AWSChimeSDKVoice/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSChimeSDKVoice/Tests/AWSChimeSDKVoiceTests/EndpointResolverTest.swift b/Sources/Services/AWSChimeSDKVoice/Tests/AWSChimeSDKVoiceTests/EndpointResolverTest.swift
index 06aa3d6862a..063196f0379 100644
--- a/Sources/Services/AWSChimeSDKVoice/Tests/AWSChimeSDKVoiceTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSChimeSDKVoice/Tests/AWSChimeSDKVoiceTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSChimeSDKVoice
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCleanRooms/Sources/AWSCleanRooms/Endpoints.swift b/Sources/Services/AWSCleanRooms/Sources/AWSCleanRooms/Endpoints.swift
index da163e2f8eb..160333206ff 100644
--- a/Sources/Services/AWSCleanRooms/Sources/AWSCleanRooms/Endpoints.swift
+++ b/Sources/Services/AWSCleanRooms/Sources/AWSCleanRooms/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCleanRooms/Tests/AWSCleanRoomsTests/EndpointResolverTest.swift b/Sources/Services/AWSCleanRooms/Tests/AWSCleanRoomsTests/EndpointResolverTest.swift
index 8a1f874cc8a..cc270147a82 100644
--- a/Sources/Services/AWSCleanRooms/Tests/AWSCleanRoomsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCleanRooms/Tests/AWSCleanRoomsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCleanRooms
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCleanRoomsML/Sources/AWSCleanRoomsML/Endpoints.swift b/Sources/Services/AWSCleanRoomsML/Sources/AWSCleanRoomsML/Endpoints.swift
index 5ff862c87c8..415e964d585 100644
--- a/Sources/Services/AWSCleanRoomsML/Sources/AWSCleanRoomsML/Endpoints.swift
+++ b/Sources/Services/AWSCleanRoomsML/Sources/AWSCleanRoomsML/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCleanRoomsML/Tests/AWSCleanRoomsMLTests/EndpointResolverTest.swift b/Sources/Services/AWSCleanRoomsML/Tests/AWSCleanRoomsMLTests/EndpointResolverTest.swift
index a311f5dddd2..e7456b27c56 100644
--- a/Sources/Services/AWSCleanRoomsML/Tests/AWSCleanRoomsMLTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCleanRoomsML/Tests/AWSCleanRoomsMLTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCleanRoomsML
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCloud9/Sources/AWSCloud9/Endpoints.swift b/Sources/Services/AWSCloud9/Sources/AWSCloud9/Endpoints.swift
index 176b0b772ad..47cad2580be 100644
--- a/Sources/Services/AWSCloud9/Sources/AWSCloud9/Endpoints.swift
+++ b/Sources/Services/AWSCloud9/Sources/AWSCloud9/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCloud9/Tests/AWSCloud9Tests/EndpointResolverTest.swift b/Sources/Services/AWSCloud9/Tests/AWSCloud9Tests/EndpointResolverTest.swift
index 42f24cf4010..0a292d95178 100644
--- a/Sources/Services/AWSCloud9/Tests/AWSCloud9Tests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCloud9/Tests/AWSCloud9Tests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCloud9
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -690,7 +691,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -729,7 +730,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -768,7 +769,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -807,7 +808,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -828,7 +829,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCloudControl/Sources/AWSCloudControl/Endpoints.swift b/Sources/Services/AWSCloudControl/Sources/AWSCloudControl/Endpoints.swift
index 56b74991c3d..40da3f5c567 100644
--- a/Sources/Services/AWSCloudControl/Sources/AWSCloudControl/Endpoints.swift
+++ b/Sources/Services/AWSCloudControl/Sources/AWSCloudControl/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCloudControl/Tests/AWSCloudControlTests/EndpointResolverTest.swift b/Sources/Services/AWSCloudControl/Tests/AWSCloudControlTests/EndpointResolverTest.swift
index ba514808583..e435ecd1fd9 100644
--- a/Sources/Services/AWSCloudControl/Tests/AWSCloudControlTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCloudControl/Tests/AWSCloudControlTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCloudControl
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -850,7 +851,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -889,7 +890,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -967,7 +968,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCloudDirectory/Sources/AWSCloudDirectory/Endpoints.swift b/Sources/Services/AWSCloudDirectory/Sources/AWSCloudDirectory/Endpoints.swift
index 510ff529057..ee67a14c7db 100644
--- a/Sources/Services/AWSCloudDirectory/Sources/AWSCloudDirectory/Endpoints.swift
+++ b/Sources/Services/AWSCloudDirectory/Sources/AWSCloudDirectory/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCloudDirectory/Tests/AWSCloudDirectoryTests/EndpointResolverTest.swift b/Sources/Services/AWSCloudDirectory/Tests/AWSCloudDirectoryTests/EndpointResolverTest.swift
index 067c825f423..d9bb9e2e0f1 100644
--- a/Sources/Services/AWSCloudDirectory/Tests/AWSCloudDirectoryTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCloudDirectory/Tests/AWSCloudDirectoryTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCloudDirectory
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -490,7 +491,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -529,7 +530,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -607,7 +608,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCloudFormation/Sources/AWSCloudFormation/Endpoints.swift b/Sources/Services/AWSCloudFormation/Sources/AWSCloudFormation/Endpoints.swift
index ab7ab6b0e53..8f2039104be 100644
--- a/Sources/Services/AWSCloudFormation/Sources/AWSCloudFormation/Endpoints.swift
+++ b/Sources/Services/AWSCloudFormation/Sources/AWSCloudFormation/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCloudFormation/Tests/AWSCloudFormationTests/EndpointResolverTest.swift b/Sources/Services/AWSCloudFormation/Tests/AWSCloudFormationTests/EndpointResolverTest.swift
index 1f1b53f0dda..d8ac4670726 100644
--- a/Sources/Services/AWSCloudFormation/Tests/AWSCloudFormationTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCloudFormation/Tests/AWSCloudFormationTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCloudFormation
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCloudFront/Sources/AWSCloudFront/Endpoints.swift b/Sources/Services/AWSCloudFront/Sources/AWSCloudFront/Endpoints.swift
index 9768199394c..2b1634c585c 100644
--- a/Sources/Services/AWSCloudFront/Sources/AWSCloudFront/Endpoints.swift
+++ b/Sources/Services/AWSCloudFront/Sources/AWSCloudFront/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCloudFront/Tests/AWSCloudFrontTests/EndpointResolverTest.swift b/Sources/Services/AWSCloudFront/Tests/AWSCloudFrontTests/EndpointResolverTest.swift
index af3164f6771..ec5d8f9a55c 100644
--- a/Sources/Services/AWSCloudFront/Tests/AWSCloudFrontTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCloudFront/Tests/AWSCloudFrontTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCloudFront
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,15 +32,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "cloudfront",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -59,15 +60,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "cloudfront",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,7 +88,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -107,15 +108,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "cloudfront",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -135,7 +136,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -155,15 +156,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "cloudfront",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -183,15 +184,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "cloudfront",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,15 +272,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "cloudfront",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -299,7 +300,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -319,7 +320,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -339,7 +340,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -359,7 +360,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -398,7 +399,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -437,7 +438,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -476,7 +477,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -515,7 +516,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -536,7 +537,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -556,7 +557,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCloudFrontKeyValueStore/Sources/AWSCloudFrontKeyValueStore/Endpoints.swift b/Sources/Services/AWSCloudFrontKeyValueStore/Sources/AWSCloudFrontKeyValueStore/Endpoints.swift
index 0595d1ddaae..c37c25d41e6 100644
--- a/Sources/Services/AWSCloudFrontKeyValueStore/Sources/AWSCloudFrontKeyValueStore/Endpoints.swift
+++ b/Sources/Services/AWSCloudFrontKeyValueStore/Sources/AWSCloudFrontKeyValueStore/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The ARN of the Key Value Store
diff --git a/Sources/Services/AWSCloudFrontKeyValueStore/Tests/AWSCloudFrontKeyValueStoreTests/EndpointResolverTest.swift b/Sources/Services/AWSCloudFrontKeyValueStore/Tests/AWSCloudFrontKeyValueStoreTests/EndpointResolverTest.swift
index 4d4da036599..c34633f1730 100644
--- a/Sources/Services/AWSCloudFrontKeyValueStore/Tests/AWSCloudFrontKeyValueStoreTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCloudFrontKeyValueStore/Tests/AWSCloudFrontKeyValueStoreTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCloudFrontKeyValueStore
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -164,7 +165,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -172,9 +173,9 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4a",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable]
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        ]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -193,7 +194,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -201,9 +202,9 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4a",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable]
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        ]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -260,7 +261,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -268,9 +269,9 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4a",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable]
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        ]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -289,7 +290,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -297,9 +298,9 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4a",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable]
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        ]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCloudHSM/Sources/AWSCloudHSM/Endpoints.swift b/Sources/Services/AWSCloudHSM/Sources/AWSCloudHSM/Endpoints.swift
index d032cd7bb7e..338f47a0f37 100644
--- a/Sources/Services/AWSCloudHSM/Sources/AWSCloudHSM/Endpoints.swift
+++ b/Sources/Services/AWSCloudHSM/Sources/AWSCloudHSM/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCloudHSM/Tests/AWSCloudHSMTests/EndpointResolverTest.swift b/Sources/Services/AWSCloudHSM/Tests/AWSCloudHSMTests/EndpointResolverTest.swift
index 76e019a7d96..6ddfba336f4 100644
--- a/Sources/Services/AWSCloudHSM/Tests/AWSCloudHSMTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCloudHSM/Tests/AWSCloudHSMTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCloudHSM
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -310,7 +311,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -349,7 +350,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -388,7 +389,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -427,7 +428,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCloudHSMV2/Sources/AWSCloudHSMV2/Endpoints.swift b/Sources/Services/AWSCloudHSMV2/Sources/AWSCloudHSMV2/Endpoints.swift
index 1eb5e4014ad..45139aecef9 100644
--- a/Sources/Services/AWSCloudHSMV2/Sources/AWSCloudHSMV2/Endpoints.swift
+++ b/Sources/Services/AWSCloudHSMV2/Sources/AWSCloudHSMV2/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCloudHSMV2/Tests/AWSCloudHSMV2Tests/EndpointResolverTest.swift b/Sources/Services/AWSCloudHSMV2/Tests/AWSCloudHSMV2Tests/EndpointResolverTest.swift
index c1919ad513f..33f2b8103c1 100644
--- a/Sources/Services/AWSCloudHSMV2/Tests/AWSCloudHSMV2Tests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCloudHSMV2/Tests/AWSCloudHSMV2Tests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCloudHSMV2
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -710,7 +711,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -749,7 +750,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -788,7 +789,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -827,7 +828,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -868,7 +869,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCloudSearch/Sources/AWSCloudSearch/Endpoints.swift b/Sources/Services/AWSCloudSearch/Sources/AWSCloudSearch/Endpoints.swift
index 20f6691a84d..59e670522bf 100644
--- a/Sources/Services/AWSCloudSearch/Sources/AWSCloudSearch/Endpoints.swift
+++ b/Sources/Services/AWSCloudSearch/Sources/AWSCloudSearch/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCloudSearch/Tests/AWSCloudSearchTests/EndpointResolverTest.swift b/Sources/Services/AWSCloudSearch/Tests/AWSCloudSearchTests/EndpointResolverTest.swift
index af1f49c8c9d..e6c6a19f2f2 100644
--- a/Sources/Services/AWSCloudSearch/Tests/AWSCloudSearchTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCloudSearch/Tests/AWSCloudSearchTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCloudSearch
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -470,7 +471,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -509,7 +510,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -587,7 +588,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -608,7 +609,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCloudSearchDomain/Sources/AWSCloudSearchDomain/Endpoints.swift b/Sources/Services/AWSCloudSearchDomain/Sources/AWSCloudSearchDomain/Endpoints.swift
index 8838e876010..cb524d3ecf6 100644
--- a/Sources/Services/AWSCloudSearchDomain/Sources/AWSCloudSearchDomain/Endpoints.swift
+++ b/Sources/Services/AWSCloudSearchDomain/Sources/AWSCloudSearchDomain/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCloudSearchDomain/Tests/AWSCloudSearchDomainTests/EndpointResolverTest.swift b/Sources/Services/AWSCloudSearchDomain/Tests/AWSCloudSearchDomainTests/EndpointResolverTest.swift
index a5bfcda5e7b..00c4ddd0e96 100644
--- a/Sources/Services/AWSCloudSearchDomain/Tests/AWSCloudSearchDomainTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCloudSearchDomain/Tests/AWSCloudSearchDomainTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCloudSearchDomain
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCloudTrail/Sources/AWSCloudTrail/Endpoints.swift b/Sources/Services/AWSCloudTrail/Sources/AWSCloudTrail/Endpoints.swift
index 9fd4ff31f7e..285cdc51fd2 100644
--- a/Sources/Services/AWSCloudTrail/Sources/AWSCloudTrail/Endpoints.swift
+++ b/Sources/Services/AWSCloudTrail/Sources/AWSCloudTrail/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCloudTrail/Tests/AWSCloudTrailTests/EndpointResolverTest.swift b/Sources/Services/AWSCloudTrail/Tests/AWSCloudTrailTests/EndpointResolverTest.swift
index f8c20b7dcc2..5a901fd63cd 100644
--- a/Sources/Services/AWSCloudTrail/Tests/AWSCloudTrailTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCloudTrail/Tests/AWSCloudTrailTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCloudTrail
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCloudTrailData/Sources/AWSCloudTrailData/Endpoints.swift b/Sources/Services/AWSCloudTrailData/Sources/AWSCloudTrailData/Endpoints.swift
index c2a6debad1f..df8830bec0b 100644
--- a/Sources/Services/AWSCloudTrailData/Sources/AWSCloudTrailData/Endpoints.swift
+++ b/Sources/Services/AWSCloudTrailData/Sources/AWSCloudTrailData/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCloudTrailData/Tests/AWSCloudTrailDataTests/EndpointResolverTest.swift b/Sources/Services/AWSCloudTrailData/Tests/AWSCloudTrailDataTests/EndpointResolverTest.swift
index 338170bc496..5b1f279b9f9 100644
--- a/Sources/Services/AWSCloudTrailData/Tests/AWSCloudTrailDataTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCloudTrailData/Tests/AWSCloudTrailDataTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCloudTrailData
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCloudWatch/Sources/AWSCloudWatch/Endpoints.swift b/Sources/Services/AWSCloudWatch/Sources/AWSCloudWatch/Endpoints.swift
index 00f4887fba9..f8c08d18004 100644
--- a/Sources/Services/AWSCloudWatch/Sources/AWSCloudWatch/Endpoints.swift
+++ b/Sources/Services/AWSCloudWatch/Sources/AWSCloudWatch/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCloudWatch/Tests/AWSCloudWatchTests/EndpointResolverTest.swift b/Sources/Services/AWSCloudWatch/Tests/AWSCloudWatchTests/EndpointResolverTest.swift
index 9010cbc2ffa..8fe9f532b0d 100644
--- a/Sources/Services/AWSCloudWatch/Tests/AWSCloudWatchTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCloudWatch/Tests/AWSCloudWatchTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCloudWatch
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCloudWatchEvents/Sources/AWSCloudWatchEvents/Endpoints.swift b/Sources/Services/AWSCloudWatchEvents/Sources/AWSCloudWatchEvents/Endpoints.swift
index 08b9dbe99c4..57e49a0051a 100644
--- a/Sources/Services/AWSCloudWatchEvents/Sources/AWSCloudWatchEvents/Endpoints.swift
+++ b/Sources/Services/AWSCloudWatchEvents/Sources/AWSCloudWatchEvents/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCloudWatchEvents/Tests/AWSCloudWatchEventsTests/EndpointResolverTest.swift b/Sources/Services/AWSCloudWatchEvents/Tests/AWSCloudWatchEventsTests/EndpointResolverTest.swift
index 877975bffeb..c76ae9207c1 100644
--- a/Sources/Services/AWSCloudWatchEvents/Tests/AWSCloudWatchEventsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCloudWatchEvents/Tests/AWSCloudWatchEventsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCloudWatchEvents
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCloudWatchLogs/Sources/AWSCloudWatchLogs/Endpoints.swift b/Sources/Services/AWSCloudWatchLogs/Sources/AWSCloudWatchLogs/Endpoints.swift
index ba552a825a0..2f779317b1b 100644
--- a/Sources/Services/AWSCloudWatchLogs/Sources/AWSCloudWatchLogs/Endpoints.swift
+++ b/Sources/Services/AWSCloudWatchLogs/Sources/AWSCloudWatchLogs/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCloudWatchLogs/Tests/AWSCloudWatchLogsTests/EndpointResolverTest.swift b/Sources/Services/AWSCloudWatchLogs/Tests/AWSCloudWatchLogsTests/EndpointResolverTest.swift
index 85930d3086f..49a04e1b415 100644
--- a/Sources/Services/AWSCloudWatchLogs/Tests/AWSCloudWatchLogsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCloudWatchLogs/Tests/AWSCloudWatchLogsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCloudWatchLogs
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCodeBuild/Sources/AWSCodeBuild/Endpoints.swift b/Sources/Services/AWSCodeBuild/Sources/AWSCodeBuild/Endpoints.swift
index b514dec551b..e8d1142a68f 100644
--- a/Sources/Services/AWSCodeBuild/Sources/AWSCodeBuild/Endpoints.swift
+++ b/Sources/Services/AWSCodeBuild/Sources/AWSCodeBuild/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCodeBuild/Tests/AWSCodeBuildTests/EndpointResolverTest.swift b/Sources/Services/AWSCodeBuild/Tests/AWSCodeBuildTests/EndpointResolverTest.swift
index a63aa841c7a..b9d1d43f375 100644
--- a/Sources/Services/AWSCodeBuild/Tests/AWSCodeBuildTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCodeBuild/Tests/AWSCodeBuildTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCodeBuild
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -830,7 +831,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -869,7 +870,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -947,7 +948,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCodeCatalyst/Sources/AWSCodeCatalyst/Endpoints.swift b/Sources/Services/AWSCodeCatalyst/Sources/AWSCodeCatalyst/Endpoints.swift
index 38da9857124..b438585a565 100644
--- a/Sources/Services/AWSCodeCatalyst/Sources/AWSCodeCatalyst/Endpoints.swift
+++ b/Sources/Services/AWSCodeCatalyst/Sources/AWSCodeCatalyst/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCodeCatalyst/Tests/AWSCodeCatalystTests/EndpointResolverTest.swift b/Sources/Services/AWSCodeCatalyst/Tests/AWSCodeCatalystTests/EndpointResolverTest.swift
index af9b97aa8f6..a54603b5673 100644
--- a/Sources/Services/AWSCodeCatalyst/Tests/AWSCodeCatalystTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCodeCatalyst/Tests/AWSCodeCatalystTests/EndpointResolverTest.swift
@@ -9,6 +9,7 @@
 
 @testable import AWSCodeCatalyst
 import XCTest
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -28,7 +29,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -45,7 +46,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -63,7 +64,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -81,7 +82,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -100,7 +101,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -118,7 +119,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -137,7 +138,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -155,7 +156,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -174,7 +175,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCodeCommit/Sources/AWSCodeCommit/Endpoints.swift b/Sources/Services/AWSCodeCommit/Sources/AWSCodeCommit/Endpoints.swift
index 713ea2947c3..951ed6c9840 100644
--- a/Sources/Services/AWSCodeCommit/Sources/AWSCodeCommit/Endpoints.swift
+++ b/Sources/Services/AWSCodeCommit/Sources/AWSCodeCommit/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCodeCommit/Tests/AWSCodeCommitTests/EndpointResolverTest.swift b/Sources/Services/AWSCodeCommit/Tests/AWSCodeCommitTests/EndpointResolverTest.swift
index a76474d77b4..575bda24bd5 100644
--- a/Sources/Services/AWSCodeCommit/Tests/AWSCodeCommitTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCodeCommit/Tests/AWSCodeCommitTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCodeCommit
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -830,7 +831,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -869,7 +870,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -947,7 +948,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCodeConnections/Sources/AWSCodeConnections/Endpoints.swift b/Sources/Services/AWSCodeConnections/Sources/AWSCodeConnections/Endpoints.swift
index a94d1b404bd..8ecc4948dcd 100644
--- a/Sources/Services/AWSCodeConnections/Sources/AWSCodeConnections/Endpoints.swift
+++ b/Sources/Services/AWSCodeConnections/Sources/AWSCodeConnections/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCodeConnections/Tests/AWSCodeConnectionsTests/EndpointResolverTest.swift b/Sources/Services/AWSCodeConnections/Tests/AWSCodeConnectionsTests/EndpointResolverTest.swift
index 4073d056eb0..4a3cbc82480 100644
--- a/Sources/Services/AWSCodeConnections/Tests/AWSCodeConnectionsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCodeConnections/Tests/AWSCodeConnectionsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCodeConnections
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCodeDeploy/Sources/AWSCodeDeploy/Endpoints.swift b/Sources/Services/AWSCodeDeploy/Sources/AWSCodeDeploy/Endpoints.swift
index 9ebd7009976..24577c7c65f 100644
--- a/Sources/Services/AWSCodeDeploy/Sources/AWSCodeDeploy/Endpoints.swift
+++ b/Sources/Services/AWSCodeDeploy/Sources/AWSCodeDeploy/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCodeDeploy/Tests/AWSCodeDeployTests/EndpointResolverTest.swift b/Sources/Services/AWSCodeDeploy/Tests/AWSCodeDeployTests/EndpointResolverTest.swift
index f5265371176..7089b490c56 100644
--- a/Sources/Services/AWSCodeDeploy/Tests/AWSCodeDeployTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCodeDeploy/Tests/AWSCodeDeployTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCodeDeploy
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCodeGuruProfiler/Sources/AWSCodeGuruProfiler/Endpoints.swift b/Sources/Services/AWSCodeGuruProfiler/Sources/AWSCodeGuruProfiler/Endpoints.swift
index a83ff3f9a52..e31514ad8a7 100644
--- a/Sources/Services/AWSCodeGuruProfiler/Sources/AWSCodeGuruProfiler/Endpoints.swift
+++ b/Sources/Services/AWSCodeGuruProfiler/Sources/AWSCodeGuruProfiler/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCodeGuruProfiler/Tests/AWSCodeGuruProfilerTests/EndpointResolverTest.swift b/Sources/Services/AWSCodeGuruProfiler/Tests/AWSCodeGuruProfilerTests/EndpointResolverTest.swift
index 65ddea10017..1bf3df68c39 100644
--- a/Sources/Services/AWSCodeGuruProfiler/Tests/AWSCodeGuruProfilerTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCodeGuruProfiler/Tests/AWSCodeGuruProfilerTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCodeGuruProfiler
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCodeGuruReviewer/Sources/AWSCodeGuruReviewer/Endpoints.swift b/Sources/Services/AWSCodeGuruReviewer/Sources/AWSCodeGuruReviewer/Endpoints.swift
index a50d1cc6a83..17ccba043a5 100644
--- a/Sources/Services/AWSCodeGuruReviewer/Sources/AWSCodeGuruReviewer/Endpoints.swift
+++ b/Sources/Services/AWSCodeGuruReviewer/Sources/AWSCodeGuruReviewer/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCodeGuruReviewer/Tests/AWSCodeGuruReviewerTests/EndpointResolverTest.swift b/Sources/Services/AWSCodeGuruReviewer/Tests/AWSCodeGuruReviewerTests/EndpointResolverTest.swift
index 11c384fbe79..43042975659 100644
--- a/Sources/Services/AWSCodeGuruReviewer/Tests/AWSCodeGuruReviewerTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCodeGuruReviewer/Tests/AWSCodeGuruReviewerTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCodeGuruReviewer
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -470,7 +471,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -509,7 +510,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -587,7 +588,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -608,7 +609,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCodeGuruSecurity/Sources/AWSCodeGuruSecurity/Endpoints.swift b/Sources/Services/AWSCodeGuruSecurity/Sources/AWSCodeGuruSecurity/Endpoints.swift
index 3776f860111..c79e64585fc 100644
--- a/Sources/Services/AWSCodeGuruSecurity/Sources/AWSCodeGuruSecurity/Endpoints.swift
+++ b/Sources/Services/AWSCodeGuruSecurity/Sources/AWSCodeGuruSecurity/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCodeGuruSecurity/Tests/AWSCodeGuruSecurityTests/EndpointResolverTest.swift b/Sources/Services/AWSCodeGuruSecurity/Tests/AWSCodeGuruSecurityTests/EndpointResolverTest.swift
index dbc3d9817e0..a878b5f31a2 100644
--- a/Sources/Services/AWSCodeGuruSecurity/Tests/AWSCodeGuruSecurityTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCodeGuruSecurity/Tests/AWSCodeGuruSecurityTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCodeGuruSecurity
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCodePipeline/Sources/AWSCodePipeline/Endpoints.swift b/Sources/Services/AWSCodePipeline/Sources/AWSCodePipeline/Endpoints.swift
index 914a4f80882..29d8782728f 100644
--- a/Sources/Services/AWSCodePipeline/Sources/AWSCodePipeline/Endpoints.swift
+++ b/Sources/Services/AWSCodePipeline/Sources/AWSCodePipeline/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCodePipeline/Tests/AWSCodePipelineTests/EndpointResolverTest.swift b/Sources/Services/AWSCodePipeline/Tests/AWSCodePipelineTests/EndpointResolverTest.swift
index f86c8ce600b..d583fef7ec6 100644
--- a/Sources/Services/AWSCodePipeline/Tests/AWSCodePipelineTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCodePipeline/Tests/AWSCodePipelineTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCodePipeline
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -770,7 +771,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -809,7 +810,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -887,7 +888,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCodeStarconnections/Sources/AWSCodeStarconnections/Endpoints.swift b/Sources/Services/AWSCodeStarconnections/Sources/AWSCodeStarconnections/Endpoints.swift
index b0fb945bb90..0106afd0662 100644
--- a/Sources/Services/AWSCodeStarconnections/Sources/AWSCodeStarconnections/Endpoints.swift
+++ b/Sources/Services/AWSCodeStarconnections/Sources/AWSCodeStarconnections/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCodeStarconnections/Tests/AWSCodeStarconnectionsTests/EndpointResolverTest.swift b/Sources/Services/AWSCodeStarconnections/Tests/AWSCodeStarconnectionsTests/EndpointResolverTest.swift
index d5250cd5de7..bc91aef10c2 100644
--- a/Sources/Services/AWSCodeStarconnections/Tests/AWSCodeStarconnectionsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCodeStarconnections/Tests/AWSCodeStarconnectionsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCodeStarconnections
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -590,7 +591,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -629,7 +630,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -707,7 +708,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCodeartifact/Sources/AWSCodeartifact/Endpoints.swift b/Sources/Services/AWSCodeartifact/Sources/AWSCodeartifact/Endpoints.swift
index 6fcb9aaaa73..60be975398c 100644
--- a/Sources/Services/AWSCodeartifact/Sources/AWSCodeartifact/Endpoints.swift
+++ b/Sources/Services/AWSCodeartifact/Sources/AWSCodeartifact/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCodeartifact/Tests/AWSCodeartifactTests/EndpointResolverTest.swift b/Sources/Services/AWSCodeartifact/Tests/AWSCodeartifactTests/EndpointResolverTest.swift
index 856e4fa5231..4b902f0c95f 100644
--- a/Sources/Services/AWSCodeartifact/Tests/AWSCodeartifactTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCodeartifact/Tests/AWSCodeartifactTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCodeartifact
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -530,7 +531,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -569,7 +570,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -608,7 +609,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -647,7 +648,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -688,7 +689,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCodestarnotifications/Sources/AWSCodestarnotifications/Endpoints.swift b/Sources/Services/AWSCodestarnotifications/Sources/AWSCodestarnotifications/Endpoints.swift
index 94ec779a658..fc03ad41200 100644
--- a/Sources/Services/AWSCodestarnotifications/Sources/AWSCodestarnotifications/Endpoints.swift
+++ b/Sources/Services/AWSCodestarnotifications/Sources/AWSCodestarnotifications/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCodestarnotifications/Tests/AWSCodestarnotificationsTests/EndpointResolverTest.swift b/Sources/Services/AWSCodestarnotifications/Tests/AWSCodestarnotificationsTests/EndpointResolverTest.swift
index 8172af5f62e..97d2f1d7e27 100644
--- a/Sources/Services/AWSCodestarnotifications/Tests/AWSCodestarnotificationsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCodestarnotifications/Tests/AWSCodestarnotificationsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCodestarnotifications
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCognitoIdentity/Sources/AWSCognitoIdentity/Endpoints.swift b/Sources/Services/AWSCognitoIdentity/Sources/AWSCognitoIdentity/Endpoints.swift
index 65ab3980d47..bf77c89b263 100644
--- a/Sources/Services/AWSCognitoIdentity/Sources/AWSCognitoIdentity/Endpoints.swift
+++ b/Sources/Services/AWSCognitoIdentity/Sources/AWSCognitoIdentity/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCognitoIdentity/Tests/AWSCognitoIdentityTests/EndpointResolverTest.swift b/Sources/Services/AWSCognitoIdentity/Tests/AWSCognitoIdentityTests/EndpointResolverTest.swift
index d1f70ad5fd4..5bb16e24c62 100644
--- a/Sources/Services/AWSCognitoIdentity/Tests/AWSCognitoIdentityTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCognitoIdentity/Tests/AWSCognitoIdentityTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCognitoIdentity
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -570,7 +571,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -609,7 +610,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -687,7 +688,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -708,7 +709,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCognitoIdentityProvider/Sources/AWSCognitoIdentityProvider/Endpoints.swift b/Sources/Services/AWSCognitoIdentityProvider/Sources/AWSCognitoIdentityProvider/Endpoints.swift
index 4928843018f..a21ea0f20d9 100644
--- a/Sources/Services/AWSCognitoIdentityProvider/Sources/AWSCognitoIdentityProvider/Endpoints.swift
+++ b/Sources/Services/AWSCognitoIdentityProvider/Sources/AWSCognitoIdentityProvider/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCognitoIdentityProvider/Tests/AWSCognitoIdentityProviderTests/EndpointResolverTest.swift b/Sources/Services/AWSCognitoIdentityProvider/Tests/AWSCognitoIdentityProviderTests/EndpointResolverTest.swift
index 9b5d747085a..fc289a81312 100644
--- a/Sources/Services/AWSCognitoIdentityProvider/Tests/AWSCognitoIdentityProviderTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCognitoIdentityProvider/Tests/AWSCognitoIdentityProviderTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCognitoIdentityProvider
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -851,7 +852,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -871,7 +872,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -891,7 +892,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -911,7 +912,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -931,7 +932,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -951,7 +952,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -971,7 +972,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1010,7 +1011,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1049,7 +1050,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1088,7 +1089,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1127,7 +1128,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1148,7 +1149,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1168,7 +1169,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCognitoSync/Sources/AWSCognitoSync/Endpoints.swift b/Sources/Services/AWSCognitoSync/Sources/AWSCognitoSync/Endpoints.swift
index 68226af737f..4d168c1e00d 100644
--- a/Sources/Services/AWSCognitoSync/Sources/AWSCognitoSync/Endpoints.swift
+++ b/Sources/Services/AWSCognitoSync/Sources/AWSCognitoSync/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCognitoSync/Tests/AWSCognitoSyncTests/EndpointResolverTest.swift b/Sources/Services/AWSCognitoSync/Tests/AWSCognitoSyncTests/EndpointResolverTest.swift
index 7aafb9179d5..539a8ff702d 100644
--- a/Sources/Services/AWSCognitoSync/Tests/AWSCognitoSyncTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCognitoSync/Tests/AWSCognitoSyncTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCognitoSync
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -490,7 +491,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -529,7 +530,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -607,7 +608,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSComprehend/Sources/AWSComprehend/Endpoints.swift b/Sources/Services/AWSComprehend/Sources/AWSComprehend/Endpoints.swift
index 1a7e52aed52..63ba453a3cb 100644
--- a/Sources/Services/AWSComprehend/Sources/AWSComprehend/Endpoints.swift
+++ b/Sources/Services/AWSComprehend/Sources/AWSComprehend/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSComprehend/Tests/AWSComprehendTests/EndpointResolverTest.swift b/Sources/Services/AWSComprehend/Tests/AWSComprehendTests/EndpointResolverTest.swift
index 1c2d950c564..8f5edc19468 100644
--- a/Sources/Services/AWSComprehend/Tests/AWSComprehendTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSComprehend/Tests/AWSComprehendTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSComprehend
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -610,7 +611,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -707,7 +708,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSComprehendMedical/Sources/AWSComprehendMedical/Endpoints.swift b/Sources/Services/AWSComprehendMedical/Sources/AWSComprehendMedical/Endpoints.swift
index 46c54338202..7d9821c4214 100644
--- a/Sources/Services/AWSComprehendMedical/Sources/AWSComprehendMedical/Endpoints.swift
+++ b/Sources/Services/AWSComprehendMedical/Sources/AWSComprehendMedical/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSComprehendMedical/Tests/AWSComprehendMedicalTests/EndpointResolverTest.swift b/Sources/Services/AWSComprehendMedical/Tests/AWSComprehendMedicalTests/EndpointResolverTest.swift
index 2d89b437df8..5beb92a2580 100644
--- a/Sources/Services/AWSComprehendMedical/Tests/AWSComprehendMedicalTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSComprehendMedical/Tests/AWSComprehendMedicalTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSComprehendMedical
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -490,7 +491,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -529,7 +530,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -607,7 +608,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSComputeOptimizer/Sources/AWSComputeOptimizer/Endpoints.swift b/Sources/Services/AWSComputeOptimizer/Sources/AWSComputeOptimizer/Endpoints.swift
index 37abeb2e5cc..191f2ecbdd6 100644
--- a/Sources/Services/AWSComputeOptimizer/Sources/AWSComputeOptimizer/Endpoints.swift
+++ b/Sources/Services/AWSComputeOptimizer/Sources/AWSComputeOptimizer/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSComputeOptimizer/Tests/AWSComputeOptimizerTests/EndpointResolverTest.swift b/Sources/Services/AWSComputeOptimizer/Tests/AWSComputeOptimizerTests/EndpointResolverTest.swift
index c301315c904..a47c409a805 100644
--- a/Sources/Services/AWSComputeOptimizer/Tests/AWSComputeOptimizerTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSComputeOptimizer/Tests/AWSComputeOptimizerTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSComputeOptimizer
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -610,7 +611,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -649,7 +650,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -688,7 +689,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -727,7 +728,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -768,7 +769,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSConfigService/Sources/AWSConfigService/Endpoints.swift b/Sources/Services/AWSConfigService/Sources/AWSConfigService/Endpoints.swift
index 38e179bbfc8..e7a378fe978 100644
--- a/Sources/Services/AWSConfigService/Sources/AWSConfigService/Endpoints.swift
+++ b/Sources/Services/AWSConfigService/Sources/AWSConfigService/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSConfigService/Tests/AWSConfigServiceTests/EndpointResolverTest.swift b/Sources/Services/AWSConfigService/Tests/AWSConfigServiceTests/EndpointResolverTest.swift
index 27e37c3ff34..528e67738c8 100644
--- a/Sources/Services/AWSConfigService/Tests/AWSConfigServiceTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSConfigService/Tests/AWSConfigServiceTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSConfigService
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSConnect/Sources/AWSConnect/Endpoints.swift b/Sources/Services/AWSConnect/Sources/AWSConnect/Endpoints.swift
index d9197dc6690..89f9c57778a 100644
--- a/Sources/Services/AWSConnect/Sources/AWSConnect/Endpoints.swift
+++ b/Sources/Services/AWSConnect/Sources/AWSConnect/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSConnect/Tests/AWSConnectTests/EndpointResolverTest.swift b/Sources/Services/AWSConnect/Tests/AWSConnectTests/EndpointResolverTest.swift
index b9653f3ac08..068ec9196ec 100644
--- a/Sources/Services/AWSConnect/Tests/AWSConnectTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSConnect/Tests/AWSConnectTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSConnect
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -510,7 +511,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -549,7 +550,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -588,7 +589,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -627,7 +628,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSConnectCampaigns/Sources/AWSConnectCampaigns/Endpoints.swift b/Sources/Services/AWSConnectCampaigns/Sources/AWSConnectCampaigns/Endpoints.swift
index cfad5e21dbb..04e08181142 100644
--- a/Sources/Services/AWSConnectCampaigns/Sources/AWSConnectCampaigns/Endpoints.swift
+++ b/Sources/Services/AWSConnectCampaigns/Sources/AWSConnectCampaigns/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSConnectCampaigns/Tests/AWSConnectCampaignsTests/EndpointResolverTest.swift b/Sources/Services/AWSConnectCampaigns/Tests/AWSConnectCampaignsTests/EndpointResolverTest.swift
index b272f76bea8..72a17543aa1 100644
--- a/Sources/Services/AWSConnectCampaigns/Tests/AWSConnectCampaignsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSConnectCampaigns/Tests/AWSConnectCampaignsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSConnectCampaigns
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -350,7 +351,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -389,7 +390,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -467,7 +468,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -508,7 +509,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSConnectCampaignsV2/Sources/AWSConnectCampaignsV2/Endpoints.swift b/Sources/Services/AWSConnectCampaignsV2/Sources/AWSConnectCampaignsV2/Endpoints.swift
index 886eff1dcf3..5fdec338bf2 100644
--- a/Sources/Services/AWSConnectCampaignsV2/Sources/AWSConnectCampaignsV2/Endpoints.swift
+++ b/Sources/Services/AWSConnectCampaignsV2/Sources/AWSConnectCampaignsV2/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSConnectCampaignsV2/Tests/AWSConnectCampaignsV2Tests/EndpointResolverTest.swift b/Sources/Services/AWSConnectCampaignsV2/Tests/AWSConnectCampaignsV2Tests/EndpointResolverTest.swift
index 5c86dafc560..a54854ec65c 100644
--- a/Sources/Services/AWSConnectCampaignsV2/Tests/AWSConnectCampaignsV2Tests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSConnectCampaignsV2/Tests/AWSConnectCampaignsV2Tests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSConnectCampaignsV2
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSConnectCases/Sources/AWSConnectCases/Endpoints.swift b/Sources/Services/AWSConnectCases/Sources/AWSConnectCases/Endpoints.swift
index 5416c603d7b..e2fc059f3ad 100644
--- a/Sources/Services/AWSConnectCases/Sources/AWSConnectCases/Endpoints.swift
+++ b/Sources/Services/AWSConnectCases/Sources/AWSConnectCases/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSConnectCases/Tests/AWSConnectCasesTests/EndpointResolverTest.swift b/Sources/Services/AWSConnectCases/Tests/AWSConnectCasesTests/EndpointResolverTest.swift
index ab2cf5df68d..841991475e5 100644
--- a/Sources/Services/AWSConnectCases/Tests/AWSConnectCasesTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSConnectCases/Tests/AWSConnectCasesTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSConnectCases
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSConnectContactLens/Sources/AWSConnectContactLens/Endpoints.swift b/Sources/Services/AWSConnectContactLens/Sources/AWSConnectContactLens/Endpoints.swift
index 3f8f4ba5d29..a462fd284c0 100644
--- a/Sources/Services/AWSConnectContactLens/Sources/AWSConnectContactLens/Endpoints.swift
+++ b/Sources/Services/AWSConnectContactLens/Sources/AWSConnectContactLens/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSConnectContactLens/Tests/AWSConnectContactLensTests/EndpointResolverTest.swift b/Sources/Services/AWSConnectContactLens/Tests/AWSConnectContactLensTests/EndpointResolverTest.swift
index 4d436ca8a2f..c91967e1c8e 100644
--- a/Sources/Services/AWSConnectContactLens/Tests/AWSConnectContactLensTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSConnectContactLens/Tests/AWSConnectContactLensTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSConnectContactLens
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -430,7 +431,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -469,7 +470,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -508,7 +509,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -547,7 +548,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -588,7 +589,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSConnectParticipant/Sources/AWSConnectParticipant/Endpoints.swift b/Sources/Services/AWSConnectParticipant/Sources/AWSConnectParticipant/Endpoints.swift
index bc988c1f803..e21af50c922 100644
--- a/Sources/Services/AWSConnectParticipant/Sources/AWSConnectParticipant/Endpoints.swift
+++ b/Sources/Services/AWSConnectParticipant/Sources/AWSConnectParticipant/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSConnectParticipant/Tests/AWSConnectParticipantTests/EndpointResolverTest.swift b/Sources/Services/AWSConnectParticipant/Tests/AWSConnectParticipantTests/EndpointResolverTest.swift
index cab716cf8e7..c39f87e0d30 100644
--- a/Sources/Services/AWSConnectParticipant/Tests/AWSConnectParticipantTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSConnectParticipant/Tests/AWSConnectParticipantTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSConnectParticipant
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -330,7 +331,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -369,7 +370,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -408,7 +409,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -447,7 +448,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSControlCatalog/Sources/AWSControlCatalog/Endpoints.swift b/Sources/Services/AWSControlCatalog/Sources/AWSControlCatalog/Endpoints.swift
index a512ca43e5f..74a1f656163 100644
--- a/Sources/Services/AWSControlCatalog/Sources/AWSControlCatalog/Endpoints.swift
+++ b/Sources/Services/AWSControlCatalog/Sources/AWSControlCatalog/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSControlCatalog/Tests/AWSControlCatalogTests/EndpointResolverTest.swift b/Sources/Services/AWSControlCatalog/Tests/AWSControlCatalogTests/EndpointResolverTest.swift
index a8f97dd7e81..15d6ba305d4 100644
--- a/Sources/Services/AWSControlCatalog/Tests/AWSControlCatalogTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSControlCatalog/Tests/AWSControlCatalogTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSControlCatalog
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSControlTower/Sources/AWSControlTower/Endpoints.swift b/Sources/Services/AWSControlTower/Sources/AWSControlTower/Endpoints.swift
index 4018800ffa2..df7c02bc812 100644
--- a/Sources/Services/AWSControlTower/Sources/AWSControlTower/Endpoints.swift
+++ b/Sources/Services/AWSControlTower/Sources/AWSControlTower/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSControlTower/Tests/AWSControlTowerTests/EndpointResolverTest.swift b/Sources/Services/AWSControlTower/Tests/AWSControlTowerTests/EndpointResolverTest.swift
index dbf9e8c5c21..ae56db6c50a 100644
--- a/Sources/Services/AWSControlTower/Tests/AWSControlTowerTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSControlTower/Tests/AWSControlTowerTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSControlTower
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -630,7 +631,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -669,7 +670,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -708,7 +709,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -747,7 +748,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -768,7 +769,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -788,7 +789,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCostExplorer/Sources/AWSCostExplorer/Endpoints.swift b/Sources/Services/AWSCostExplorer/Sources/AWSCostExplorer/Endpoints.swift
index 9d3b65a0c1d..1eadc18667d 100644
--- a/Sources/Services/AWSCostExplorer/Sources/AWSCostExplorer/Endpoints.swift
+++ b/Sources/Services/AWSCostExplorer/Sources/AWSCostExplorer/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCostExplorer/Tests/AWSCostExplorerTests/EndpointResolverTest.swift b/Sources/Services/AWSCostExplorer/Tests/AWSCostExplorerTests/EndpointResolverTest.swift
index 6296d104886..98331a98840 100644
--- a/Sources/Services/AWSCostExplorer/Tests/AWSCostExplorerTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCostExplorer/Tests/AWSCostExplorerTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCostExplorer
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,15 +32,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "ce",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -59,7 +60,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -79,7 +80,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -99,7 +100,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -119,15 +120,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "ce",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -147,15 +148,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "ce",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -175,7 +176,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -195,7 +196,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -215,7 +216,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -235,15 +236,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "ce",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -263,7 +264,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -283,7 +284,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -303,7 +304,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -323,7 +324,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -343,15 +344,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "ce",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -390,7 +391,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -429,15 +430,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "ce",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -457,15 +458,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "ce",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -504,7 +505,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -543,15 +544,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "ce",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,15 +572,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "ce",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -599,15 +600,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "ce",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCostOptimizationHub/Sources/AWSCostOptimizationHub/Endpoints.swift b/Sources/Services/AWSCostOptimizationHub/Sources/AWSCostOptimizationHub/Endpoints.swift
index 2f944aa90e4..791bf28414c 100644
--- a/Sources/Services/AWSCostOptimizationHub/Sources/AWSCostOptimizationHub/Endpoints.swift
+++ b/Sources/Services/AWSCostOptimizationHub/Sources/AWSCostOptimizationHub/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCostOptimizationHub/Tests/AWSCostOptimizationHubTests/EndpointResolverTest.swift b/Sources/Services/AWSCostOptimizationHub/Tests/AWSCostOptimizationHubTests/EndpointResolverTest.swift
index 32feec33b6c..72077ad603f 100644
--- a/Sources/Services/AWSCostOptimizationHub/Tests/AWSCostOptimizationHubTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCostOptimizationHub/Tests/AWSCostOptimizationHubTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCostOptimizationHub
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCostandUsageReportService/Sources/AWSCostandUsageReportService/Endpoints.swift b/Sources/Services/AWSCostandUsageReportService/Sources/AWSCostandUsageReportService/Endpoints.swift
index 2a50ca26e08..e3bbe7e7466 100644
--- a/Sources/Services/AWSCostandUsageReportService/Sources/AWSCostandUsageReportService/Endpoints.swift
+++ b/Sources/Services/AWSCostandUsageReportService/Sources/AWSCostandUsageReportService/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCostandUsageReportService/Tests/AWSCostandUsageReportServiceTests/EndpointResolverTest.swift b/Sources/Services/AWSCostandUsageReportService/Tests/AWSCostandUsageReportServiceTests/EndpointResolverTest.swift
index 5953756ecb7..5ad107e4261 100644
--- a/Sources/Services/AWSCostandUsageReportService/Tests/AWSCostandUsageReportServiceTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCostandUsageReportService/Tests/AWSCostandUsageReportServiceTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCostandUsageReportService
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -310,7 +311,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -349,7 +350,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -388,7 +389,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -427,7 +428,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSCustomerProfiles/Sources/AWSCustomerProfiles/Endpoints.swift b/Sources/Services/AWSCustomerProfiles/Sources/AWSCustomerProfiles/Endpoints.swift
index 473acaa2ff8..d68bee685eb 100644
--- a/Sources/Services/AWSCustomerProfiles/Sources/AWSCustomerProfiles/Endpoints.swift
+++ b/Sources/Services/AWSCustomerProfiles/Sources/AWSCustomerProfiles/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSCustomerProfiles/Tests/AWSCustomerProfilesTests/EndpointResolverTest.swift b/Sources/Services/AWSCustomerProfiles/Tests/AWSCustomerProfilesTests/EndpointResolverTest.swift
index c698daecbcc..d0dc4fad019 100644
--- a/Sources/Services/AWSCustomerProfiles/Tests/AWSCustomerProfilesTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSCustomerProfiles/Tests/AWSCustomerProfilesTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSCustomerProfiles
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -470,7 +471,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -509,7 +510,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -587,7 +588,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -608,7 +609,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDAX/Sources/AWSDAX/Endpoints.swift b/Sources/Services/AWSDAX/Sources/AWSDAX/Endpoints.swift
index 5dcaec4fc10..b9d9fc472ee 100644
--- a/Sources/Services/AWSDAX/Sources/AWSDAX/Endpoints.swift
+++ b/Sources/Services/AWSDAX/Sources/AWSDAX/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSDAX/Tests/AWSDAXTests/EndpointResolverTest.swift b/Sources/Services/AWSDAX/Tests/AWSDAXTests/EndpointResolverTest.swift
index c440fce4deb..56ff5291d1b 100644
--- a/Sources/Services/AWSDAX/Tests/AWSDAXTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDAX/Tests/AWSDAXTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDAX
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -550,7 +551,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -589,7 +590,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -667,7 +668,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -688,7 +689,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -708,7 +709,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDLM/Sources/AWSDLM/Endpoints.swift b/Sources/Services/AWSDLM/Sources/AWSDLM/Endpoints.swift
index 3282e2cc8f6..895d162e556 100644
--- a/Sources/Services/AWSDLM/Sources/AWSDLM/Endpoints.swift
+++ b/Sources/Services/AWSDLM/Sources/AWSDLM/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSDLM/Tests/AWSDLMTests/EndpointResolverTest.swift b/Sources/Services/AWSDLM/Tests/AWSDLMTests/EndpointResolverTest.swift
index 10c5415410a..e48a1c6e317 100644
--- a/Sources/Services/AWSDLM/Tests/AWSDLMTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDLM/Tests/AWSDLMTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDLM
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -770,7 +771,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -809,7 +810,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -887,7 +888,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDSQL/Sources/AWSDSQL/Endpoints.swift b/Sources/Services/AWSDSQL/Sources/AWSDSQL/Endpoints.swift
index 44dceb61e81..cac68eed447 100644
--- a/Sources/Services/AWSDSQL/Sources/AWSDSQL/Endpoints.swift
+++ b/Sources/Services/AWSDSQL/Sources/AWSDSQL/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSDSQL/Tests/AWSDSQLTests/EndpointResolverTest.swift b/Sources/Services/AWSDSQL/Tests/AWSDSQLTests/EndpointResolverTest.swift
index 9710f12372e..9294fbd1cb4 100644
--- a/Sources/Services/AWSDSQL/Tests/AWSDSQLTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDSQL/Tests/AWSDSQLTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDSQL
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -67,7 +68,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -86,7 +87,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -105,7 +106,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -124,7 +125,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -143,7 +144,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -162,7 +163,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -181,7 +182,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -200,7 +201,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -219,7 +220,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -238,7 +239,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -257,7 +258,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -276,7 +277,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -295,7 +296,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -314,7 +315,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDataBrew/Sources/AWSDataBrew/Endpoints.swift b/Sources/Services/AWSDataBrew/Sources/AWSDataBrew/Endpoints.swift
index afb68ef3b48..1d317d904eb 100644
--- a/Sources/Services/AWSDataBrew/Sources/AWSDataBrew/Endpoints.swift
+++ b/Sources/Services/AWSDataBrew/Sources/AWSDataBrew/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSDataBrew/Tests/AWSDataBrewTests/EndpointResolverTest.swift b/Sources/Services/AWSDataBrew/Tests/AWSDataBrewTests/EndpointResolverTest.swift
index a1176eca904..b4fa5fafae2 100644
--- a/Sources/Services/AWSDataBrew/Tests/AWSDataBrewTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDataBrew/Tests/AWSDataBrewTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDataBrew
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -710,7 +711,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -749,7 +750,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -788,7 +789,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -827,7 +828,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -868,7 +869,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDataExchange/Sources/AWSDataExchange/Endpoints.swift b/Sources/Services/AWSDataExchange/Sources/AWSDataExchange/Endpoints.swift
index 797af17ae3f..fd2be134e3a 100644
--- a/Sources/Services/AWSDataExchange/Sources/AWSDataExchange/Endpoints.swift
+++ b/Sources/Services/AWSDataExchange/Sources/AWSDataExchange/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSDataExchange/Tests/AWSDataExchangeTests/EndpointResolverTest.swift b/Sources/Services/AWSDataExchange/Tests/AWSDataExchangeTests/EndpointResolverTest.swift
index 899880a268e..f2d357b3973 100644
--- a/Sources/Services/AWSDataExchange/Tests/AWSDataExchangeTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDataExchange/Tests/AWSDataExchangeTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDataExchange
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -490,7 +491,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -529,7 +530,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -607,7 +608,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDataPipeline/Sources/AWSDataPipeline/Endpoints.swift b/Sources/Services/AWSDataPipeline/Sources/AWSDataPipeline/Endpoints.swift
index 4af999e5c1d..e37c02abbc6 100644
--- a/Sources/Services/AWSDataPipeline/Sources/AWSDataPipeline/Endpoints.swift
+++ b/Sources/Services/AWSDataPipeline/Sources/AWSDataPipeline/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSDataPipeline/Tests/AWSDataPipelineTests/EndpointResolverTest.swift b/Sources/Services/AWSDataPipeline/Tests/AWSDataPipelineTests/EndpointResolverTest.swift
index e10f1530718..826e15af009 100644
--- a/Sources/Services/AWSDataPipeline/Tests/AWSDataPipelineTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDataPipeline/Tests/AWSDataPipelineTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDataPipeline
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -390,7 +391,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -487,7 +488,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -508,7 +509,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -528,7 +529,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDataSync/Sources/AWSDataSync/Endpoints.swift b/Sources/Services/AWSDataSync/Sources/AWSDataSync/Endpoints.swift
index effdfe0a156..051d0574325 100644
--- a/Sources/Services/AWSDataSync/Sources/AWSDataSync/Endpoints.swift
+++ b/Sources/Services/AWSDataSync/Sources/AWSDataSync/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSDataSync/Tests/AWSDataSyncTests/EndpointResolverTest.swift b/Sources/Services/AWSDataSync/Tests/AWSDataSyncTests/EndpointResolverTest.swift
index e7713377b8d..c694cc00770 100644
--- a/Sources/Services/AWSDataSync/Tests/AWSDataSyncTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDataSync/Tests/AWSDataSyncTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDataSync
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -830,7 +831,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -869,7 +870,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -947,7 +948,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDataZone/Sources/AWSDataZone/Endpoints.swift b/Sources/Services/AWSDataZone/Sources/AWSDataZone/Endpoints.swift
index d14623e6072..18455b68844 100644
--- a/Sources/Services/AWSDataZone/Sources/AWSDataZone/Endpoints.swift
+++ b/Sources/Services/AWSDataZone/Sources/AWSDataZone/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSDataZone/Tests/AWSDataZoneTests/EndpointResolverTest.swift b/Sources/Services/AWSDataZone/Tests/AWSDataZoneTests/EndpointResolverTest.swift
index 1994d8aded8..e809da07f97 100644
--- a/Sources/Services/AWSDataZone/Tests/AWSDataZoneTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDataZone/Tests/AWSDataZoneTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDataZone
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -49,7 +50,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -68,7 +69,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,7 +88,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -106,7 +107,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -125,7 +126,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -145,7 +146,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -164,7 +165,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDatabaseMigrationService/Sources/AWSDatabaseMigrationService/Endpoints.swift b/Sources/Services/AWSDatabaseMigrationService/Sources/AWSDatabaseMigrationService/Endpoints.swift
index 3cf9cf0ae94..ce1476f0725 100644
--- a/Sources/Services/AWSDatabaseMigrationService/Sources/AWSDatabaseMigrationService/Endpoints.swift
+++ b/Sources/Services/AWSDatabaseMigrationService/Sources/AWSDatabaseMigrationService/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSDatabaseMigrationService/Tests/AWSDatabaseMigrationServiceTests/EndpointResolverTest.swift b/Sources/Services/AWSDatabaseMigrationService/Tests/AWSDatabaseMigrationServiceTests/EndpointResolverTest.swift
index c8c8d0dd008..abfa39eee69 100644
--- a/Sources/Services/AWSDatabaseMigrationService/Tests/AWSDatabaseMigrationServiceTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDatabaseMigrationService/Tests/AWSDatabaseMigrationServiceTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDatabaseMigrationService
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -851,7 +852,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -871,7 +872,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -929,7 +930,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -949,7 +950,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1028,7 +1029,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDeadline/Sources/AWSDeadline/Endpoints.swift b/Sources/Services/AWSDeadline/Sources/AWSDeadline/Endpoints.swift
index 05dc699b4a2..3cb93015466 100644
--- a/Sources/Services/AWSDeadline/Sources/AWSDeadline/Endpoints.swift
+++ b/Sources/Services/AWSDeadline/Sources/AWSDeadline/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSDeadline/Tests/AWSDeadlineTests/EndpointResolverTest.swift b/Sources/Services/AWSDeadline/Tests/AWSDeadlineTests/EndpointResolverTest.swift
index 79439094d2b..4f7f31dd3a3 100644
--- a/Sources/Services/AWSDeadline/Tests/AWSDeadlineTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDeadline/Tests/AWSDeadlineTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDeadline
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDetective/Sources/AWSDetective/Endpoints.swift b/Sources/Services/AWSDetective/Sources/AWSDetective/Endpoints.swift
index fd071134f78..21ca556c180 100644
--- a/Sources/Services/AWSDetective/Sources/AWSDetective/Endpoints.swift
+++ b/Sources/Services/AWSDetective/Sources/AWSDetective/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSDetective/Tests/AWSDetectiveTests/EndpointResolverTest.swift b/Sources/Services/AWSDetective/Tests/AWSDetectiveTests/EndpointResolverTest.swift
index 83be6d72d0f..24502e9bd68 100644
--- a/Sources/Services/AWSDetective/Tests/AWSDetectiveTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDetective/Tests/AWSDetectiveTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDetective
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,7 +88,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -107,7 +108,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -127,7 +128,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -147,7 +148,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -167,7 +168,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -187,7 +188,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -207,7 +208,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -227,7 +228,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -247,7 +248,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -267,7 +268,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -287,7 +288,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -307,7 +308,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -346,7 +347,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -385,7 +386,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -424,7 +425,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -463,7 +464,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -502,7 +503,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -541,7 +542,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -580,7 +581,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -619,7 +620,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDevOpsGuru/Sources/AWSDevOpsGuru/Endpoints.swift b/Sources/Services/AWSDevOpsGuru/Sources/AWSDevOpsGuru/Endpoints.swift
index 29fbd129c44..efc6001afc5 100644
--- a/Sources/Services/AWSDevOpsGuru/Sources/AWSDevOpsGuru/Endpoints.swift
+++ b/Sources/Services/AWSDevOpsGuru/Sources/AWSDevOpsGuru/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSDevOpsGuru/Tests/AWSDevOpsGuruTests/EndpointResolverTest.swift b/Sources/Services/AWSDevOpsGuru/Tests/AWSDevOpsGuruTests/EndpointResolverTest.swift
index 87ea6b2434b..11007f75e60 100644
--- a/Sources/Services/AWSDevOpsGuru/Tests/AWSDevOpsGuruTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDevOpsGuru/Tests/AWSDevOpsGuruTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDevOpsGuru
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -490,7 +491,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -529,7 +530,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -607,7 +608,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDeviceFarm/Sources/AWSDeviceFarm/Endpoints.swift b/Sources/Services/AWSDeviceFarm/Sources/AWSDeviceFarm/Endpoints.swift
index a01282abf12..e9aa3eb0556 100644
--- a/Sources/Services/AWSDeviceFarm/Sources/AWSDeviceFarm/Endpoints.swift
+++ b/Sources/Services/AWSDeviceFarm/Sources/AWSDeviceFarm/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSDeviceFarm/Tests/AWSDeviceFarmTests/EndpointResolverTest.swift b/Sources/Services/AWSDeviceFarm/Tests/AWSDeviceFarmTests/EndpointResolverTest.swift
index 8df0c0e3e49..e5dd8d775a6 100644
--- a/Sources/Services/AWSDeviceFarm/Tests/AWSDeviceFarmTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDeviceFarm/Tests/AWSDeviceFarmTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDeviceFarm
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -310,7 +311,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -349,7 +350,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -388,7 +389,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -427,7 +428,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDirectConnect/Sources/AWSDirectConnect/Endpoints.swift b/Sources/Services/AWSDirectConnect/Sources/AWSDirectConnect/Endpoints.swift
index 304e6d0a679..a622a667536 100644
--- a/Sources/Services/AWSDirectConnect/Sources/AWSDirectConnect/Endpoints.swift
+++ b/Sources/Services/AWSDirectConnect/Sources/AWSDirectConnect/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSDirectConnect/Tests/AWSDirectConnectTests/EndpointResolverTest.swift b/Sources/Services/AWSDirectConnect/Tests/AWSDirectConnectTests/EndpointResolverTest.swift
index bd9ba1a0fe6..a2008862c80 100644
--- a/Sources/Services/AWSDirectConnect/Tests/AWSDirectConnectTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDirectConnect/Tests/AWSDirectConnectTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDirectConnect
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -850,7 +851,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -889,7 +890,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDirectoryService/Sources/AWSDirectoryService/Endpoints.swift b/Sources/Services/AWSDirectoryService/Sources/AWSDirectoryService/Endpoints.swift
index 323987906e5..a1788926c6d 100644
--- a/Sources/Services/AWSDirectoryService/Sources/AWSDirectoryService/Endpoints.swift
+++ b/Sources/Services/AWSDirectoryService/Sources/AWSDirectoryService/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSDirectoryService/Tests/AWSDirectoryServiceTests/EndpointResolverTest.swift b/Sources/Services/AWSDirectoryService/Tests/AWSDirectoryServiceTests/EndpointResolverTest.swift
index 5f6ad943d66..cbde8c9ee15 100644
--- a/Sources/Services/AWSDirectoryService/Tests/AWSDirectoryServiceTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDirectoryService/Tests/AWSDirectoryServiceTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDirectoryService
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -850,7 +851,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -889,7 +890,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDirectoryServiceData/Sources/AWSDirectoryServiceData/Endpoints.swift b/Sources/Services/AWSDirectoryServiceData/Sources/AWSDirectoryServiceData/Endpoints.swift
index 9e99d226abe..77883dd95f3 100644
--- a/Sources/Services/AWSDirectoryServiceData/Sources/AWSDirectoryServiceData/Endpoints.swift
+++ b/Sources/Services/AWSDirectoryServiceData/Sources/AWSDirectoryServiceData/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSDirectoryServiceData/Tests/AWSDirectoryServiceDataTests/EndpointResolverTest.swift b/Sources/Services/AWSDirectoryServiceData/Tests/AWSDirectoryServiceDataTests/EndpointResolverTest.swift
index 5676dd486a5..1114479d863 100644
--- a/Sources/Services/AWSDirectoryServiceData/Tests/AWSDirectoryServiceDataTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDirectoryServiceData/Tests/AWSDirectoryServiceDataTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDirectoryServiceData
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDocDB/Sources/AWSDocDB/Endpoints.swift b/Sources/Services/AWSDocDB/Sources/AWSDocDB/Endpoints.swift
index ca1de3db84c..edad7667086 100644
--- a/Sources/Services/AWSDocDB/Sources/AWSDocDB/Endpoints.swift
+++ b/Sources/Services/AWSDocDB/Sources/AWSDocDB/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSDocDB/Tests/AWSDocDBTests/EndpointResolverTest.swift b/Sources/Services/AWSDocDB/Tests/AWSDocDBTests/EndpointResolverTest.swift
index 41527aa081f..3c8922a1352 100644
--- a/Sources/Services/AWSDocDB/Tests/AWSDocDBTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDocDB/Tests/AWSDocDBTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDocDB
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -851,7 +852,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -890,7 +891,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -929,7 +930,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1028,7 +1029,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDocDBElastic/Sources/AWSDocDBElastic/Endpoints.swift b/Sources/Services/AWSDocDBElastic/Sources/AWSDocDBElastic/Endpoints.swift
index 56fc72b7de1..9bba8ff6f34 100644
--- a/Sources/Services/AWSDocDBElastic/Sources/AWSDocDBElastic/Endpoints.swift
+++ b/Sources/Services/AWSDocDBElastic/Sources/AWSDocDBElastic/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSDocDBElastic/Tests/AWSDocDBElasticTests/EndpointResolverTest.swift b/Sources/Services/AWSDocDBElastic/Tests/AWSDocDBElasticTests/EndpointResolverTest.swift
index 6ba46a1811b..28f8c113093 100644
--- a/Sources/Services/AWSDocDBElastic/Tests/AWSDocDBElasticTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDocDBElastic/Tests/AWSDocDBElasticTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDocDBElastic
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDrs/Sources/AWSDrs/Endpoints.swift b/Sources/Services/AWSDrs/Sources/AWSDrs/Endpoints.swift
index 0f77eaf8d9d..6b5e3f16889 100644
--- a/Sources/Services/AWSDrs/Sources/AWSDrs/Endpoints.swift
+++ b/Sources/Services/AWSDrs/Sources/AWSDrs/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSDrs/Tests/AWSDrsTests/EndpointResolverTest.swift b/Sources/Services/AWSDrs/Tests/AWSDrsTests/EndpointResolverTest.swift
index 47eee3b1cd5..698e7e04b4f 100644
--- a/Sources/Services/AWSDrs/Tests/AWSDrsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDrs/Tests/AWSDrsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDrs
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -690,7 +691,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -729,7 +730,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -768,7 +769,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -807,7 +808,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -828,7 +829,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDynamoDB/Sources/AWSDynamoDB/Endpoints.swift b/Sources/Services/AWSDynamoDB/Sources/AWSDynamoDB/Endpoints.swift
index 4d58fd77dd1..55a259d974a 100644
--- a/Sources/Services/AWSDynamoDB/Sources/AWSDynamoDB/Endpoints.swift
+++ b/Sources/Services/AWSDynamoDB/Sources/AWSDynamoDB/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// The AWS AccountId used for the request.
     public let accountId: Swift.String?
     /// The AccountId Endpoint Mode.
diff --git a/Sources/Services/AWSDynamoDB/Tests/AWSDynamoDBTests/EndpointResolverTest.swift b/Sources/Services/AWSDynamoDB/Tests/AWSDynamoDBTests/EndpointResolverTest.swift
index e0632e8966c..c7bd5e76f71 100644
--- a/Sources/Services/AWSDynamoDB/Tests/AWSDynamoDBTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDynamoDB/Tests/AWSDynamoDBTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDynamoDB
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,15 +372,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "dynamodb",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -399,7 +400,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -419,7 +420,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -439,7 +440,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -459,7 +460,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -479,7 +480,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -499,7 +500,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -519,7 +520,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -539,7 +540,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -559,7 +560,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -579,7 +580,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -599,7 +600,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -619,7 +620,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -639,7 +640,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -659,7 +660,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -679,7 +680,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -699,7 +700,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -719,7 +720,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -739,7 +740,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -759,7 +760,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -779,7 +780,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -799,7 +800,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -819,7 +820,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -839,7 +840,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -859,7 +860,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -879,7 +880,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -918,7 +919,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -957,7 +958,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -996,7 +997,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1036,7 +1037,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1056,7 +1057,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1201,7 +1202,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1227,7 +1228,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1254,7 +1255,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1281,7 +1282,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1308,7 +1309,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1335,7 +1336,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1362,7 +1363,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1385,7 +1386,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1474,7 +1475,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1497,7 +1498,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1520,7 +1521,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1543,7 +1544,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1640,7 +1641,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1666,7 +1667,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1688,7 +1689,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1777,7 +1778,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1803,7 +1804,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1830,7 +1831,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1857,7 +1858,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1884,7 +1885,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1911,7 +1912,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1938,7 +1939,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1961,7 +1962,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2050,7 +2051,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2073,7 +2074,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2096,7 +2097,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2119,7 +2120,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2216,7 +2217,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2242,7 +2243,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2264,7 +2265,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2353,7 +2354,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2379,7 +2380,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2406,7 +2407,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2433,7 +2434,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2460,7 +2461,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2487,7 +2488,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2514,7 +2515,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2537,7 +2538,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2626,7 +2627,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2649,7 +2650,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2672,7 +2673,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2695,7 +2696,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2792,7 +2793,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2818,7 +2819,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2840,7 +2841,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2925,15 +2926,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2958,15 +2959,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2992,15 +2993,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3026,15 +3027,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3060,15 +3061,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3094,15 +3095,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3128,15 +3129,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3158,15 +3159,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3251,15 +3252,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3281,15 +3282,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3311,15 +3312,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3341,15 +3342,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3442,15 +3443,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3475,15 +3476,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3504,15 +3505,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3597,15 +3598,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3630,15 +3631,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3664,15 +3665,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3698,15 +3699,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3732,15 +3733,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3766,15 +3767,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3800,15 +3801,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3830,15 +3831,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3923,15 +3924,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3953,15 +3954,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3983,15 +3984,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4013,15 +4014,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4114,15 +4115,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4147,15 +4148,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4176,15 +4177,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4269,15 +4270,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4302,15 +4303,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4336,15 +4337,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4370,15 +4371,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4404,15 +4405,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4438,15 +4439,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4472,15 +4473,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4502,15 +4503,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4595,15 +4596,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4625,15 +4626,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4655,15 +4656,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4685,15 +4686,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4786,15 +4787,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4819,15 +4820,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4848,15 +4849,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
-                        "signingRegion": "us-east-1",
                         "signingName": "dynamodb",
-                        "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        "name": "sigv4",
+                        "signingRegion": "us-east-1"
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4878,7 +4879,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4900,7 +4901,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4922,7 +4923,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4944,7 +4945,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4969,7 +4970,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4995,7 +4996,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5021,7 +5022,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5047,7 +5048,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5073,7 +5074,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5099,7 +5100,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5142,7 +5143,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5164,7 +5165,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5186,7 +5187,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5208,7 +5209,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5230,7 +5231,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5252,7 +5253,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5274,7 +5275,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5298,7 +5299,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5322,7 +5323,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5346,7 +5347,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5370,7 +5371,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5395,7 +5396,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5416,7 +5417,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5501,7 +5502,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5526,7 +5527,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5552,7 +5553,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5578,7 +5579,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5604,7 +5605,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5630,7 +5631,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5656,7 +5657,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5762,7 +5763,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5918,7 +5919,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5943,7 +5944,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6522,7 +6523,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6544,7 +6545,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6566,7 +6567,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6588,7 +6589,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6613,7 +6614,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6639,7 +6640,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6665,7 +6666,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6691,7 +6692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6717,7 +6718,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6743,7 +6744,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6765,7 +6766,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6787,7 +6788,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6809,7 +6810,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6831,7 +6832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6853,7 +6854,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6875,7 +6876,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6897,7 +6898,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6919,7 +6920,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6943,7 +6944,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6967,7 +6968,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6991,7 +6992,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7015,7 +7016,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7040,7 +7041,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7061,7 +7062,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7083,7 +7084,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7105,7 +7106,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7127,7 +7128,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7149,7 +7150,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7174,7 +7175,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7200,7 +7201,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7226,7 +7227,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7252,7 +7253,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7278,7 +7279,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7304,7 +7305,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7326,7 +7327,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7348,7 +7349,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7370,7 +7371,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7392,7 +7393,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7414,7 +7415,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7436,7 +7437,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7458,7 +7459,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7480,7 +7481,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7504,7 +7505,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7528,7 +7529,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7552,7 +7553,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7576,7 +7577,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7601,7 +7602,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7622,7 +7623,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7665,7 +7666,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7708,7 +7709,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7733,7 +7734,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7759,7 +7760,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7785,7 +7786,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7811,7 +7812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7837,7 +7838,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7863,7 +7864,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7885,7 +7886,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7928,7 +7929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7971,7 +7972,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7993,7 +7994,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8015,7 +8016,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8037,7 +8038,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8084,7 +8085,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8131,7 +8132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8156,7 +8157,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8177,7 +8178,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8199,7 +8200,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8221,7 +8222,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8243,7 +8244,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8265,7 +8266,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8290,7 +8291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8316,7 +8317,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8342,7 +8343,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8368,7 +8369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8394,7 +8395,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8420,7 +8421,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8442,7 +8443,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8464,7 +8465,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8486,7 +8487,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8508,7 +8509,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8530,7 +8531,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8552,7 +8553,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8574,7 +8575,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8596,7 +8597,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8620,7 +8621,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8644,7 +8645,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8668,7 +8669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8692,7 +8693,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8717,7 +8718,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -8738,7 +8739,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSDynamoDBStreams/Sources/AWSDynamoDBStreams/Endpoints.swift b/Sources/Services/AWSDynamoDBStreams/Sources/AWSDynamoDBStreams/Endpoints.swift
index 6fafe336dda..815422fa2b2 100644
--- a/Sources/Services/AWSDynamoDBStreams/Sources/AWSDynamoDBStreams/Endpoints.swift
+++ b/Sources/Services/AWSDynamoDBStreams/Sources/AWSDynamoDBStreams/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSDynamoDBStreams/Tests/AWSDynamoDBStreamsTests/EndpointResolverTest.swift b/Sources/Services/AWSDynamoDBStreams/Tests/AWSDynamoDBStreamsTests/EndpointResolverTest.swift
index a56d4dc86ef..418581250e1 100644
--- a/Sources/Services/AWSDynamoDBStreams/Tests/AWSDynamoDBStreamsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSDynamoDBStreams/Tests/AWSDynamoDBStreamsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSDynamoDBStreams
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,15 +352,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "dynamodb",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -379,7 +380,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -399,7 +400,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -419,7 +420,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -439,7 +440,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -459,7 +460,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -479,7 +480,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -499,7 +500,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -519,7 +520,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -539,7 +540,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -559,7 +560,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -579,7 +580,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -599,7 +600,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -619,7 +620,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -639,7 +640,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -659,7 +660,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -679,7 +680,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -699,7 +700,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -719,7 +720,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -739,7 +740,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -759,7 +760,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -779,7 +780,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -818,7 +819,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -857,7 +858,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -896,7 +897,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -936,7 +937,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -956,7 +957,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSEBS/Sources/AWSEBS/Endpoints.swift b/Sources/Services/AWSEBS/Sources/AWSEBS/Endpoints.swift
index 428c7a6898c..63aad1157e3 100644
--- a/Sources/Services/AWSEBS/Sources/AWSEBS/Endpoints.swift
+++ b/Sources/Services/AWSEBS/Sources/AWSEBS/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSEBS/Tests/AWSEBSTests/EndpointResolverTest.swift b/Sources/Services/AWSEBS/Tests/AWSEBSTests/EndpointResolverTest.swift
index f981eb30577..c7788c8e677 100644
--- a/Sources/Services/AWSEBS/Tests/AWSEBSTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSEBS/Tests/AWSEBSTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSEBS
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -850,7 +851,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -889,7 +890,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSEC2/Sources/AWSEC2/Endpoints.swift b/Sources/Services/AWSEC2/Sources/AWSEC2/Endpoints.swift
index 2614a95746e..e23d9ff991a 100644
--- a/Sources/Services/AWSEC2/Sources/AWSEC2/Endpoints.swift
+++ b/Sources/Services/AWSEC2/Sources/AWSEC2/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSEC2/Tests/AWSEC2Tests/EndpointResolverTest.swift b/Sources/Services/AWSEC2/Tests/AWSEC2Tests/EndpointResolverTest.swift
index ff970c280e6..ea7ce5eb0af 100644
--- a/Sources/Services/AWSEC2/Tests/AWSEC2Tests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSEC2/Tests/AWSEC2Tests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSEC2
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -851,7 +852,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -871,7 +872,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -891,7 +892,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -911,7 +912,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -931,7 +932,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -970,7 +971,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1009,7 +1010,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1048,7 +1049,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1088,7 +1089,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1108,7 +1109,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSEC2InstanceConnect/Sources/AWSEC2InstanceConnect/Endpoints.swift b/Sources/Services/AWSEC2InstanceConnect/Sources/AWSEC2InstanceConnect/Endpoints.swift
index ef953c056c2..02c667453b3 100644
--- a/Sources/Services/AWSEC2InstanceConnect/Sources/AWSEC2InstanceConnect/Endpoints.swift
+++ b/Sources/Services/AWSEC2InstanceConnect/Sources/AWSEC2InstanceConnect/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSEC2InstanceConnect/Tests/AWSEC2InstanceConnectTests/EndpointResolverTest.swift b/Sources/Services/AWSEC2InstanceConnect/Tests/AWSEC2InstanceConnectTests/EndpointResolverTest.swift
index 7ffa3e5f4b2..04faa9b3d8c 100644
--- a/Sources/Services/AWSEC2InstanceConnect/Tests/AWSEC2InstanceConnectTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSEC2InstanceConnect/Tests/AWSEC2InstanceConnectTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSEC2InstanceConnect
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSECR/Sources/AWSECR/Endpoints.swift b/Sources/Services/AWSECR/Sources/AWSECR/Endpoints.swift
index c7890f4ad26..384afaadc97 100644
--- a/Sources/Services/AWSECR/Sources/AWSECR/Endpoints.swift
+++ b/Sources/Services/AWSECR/Sources/AWSECR/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSECR/Tests/AWSECRTests/EndpointResolverTest.swift b/Sources/Services/AWSECR/Tests/AWSECRTests/EndpointResolverTest.swift
index 2ac96c314f9..935dcb519a9 100644
--- a/Sources/Services/AWSECR/Tests/AWSECRTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSECR/Tests/AWSECRTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSECR
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSECRPUBLIC/Sources/AWSECRPUBLIC/Endpoints.swift b/Sources/Services/AWSECRPUBLIC/Sources/AWSECRPUBLIC/Endpoints.swift
index 75cf4808117..e2364d02c6d 100644
--- a/Sources/Services/AWSECRPUBLIC/Sources/AWSECRPUBLIC/Endpoints.swift
+++ b/Sources/Services/AWSECRPUBLIC/Sources/AWSECRPUBLIC/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSECRPUBLIC/Tests/AWSECRPUBLICTests/EndpointResolverTest.swift b/Sources/Services/AWSECRPUBLIC/Tests/AWSECRPUBLICTests/EndpointResolverTest.swift
index a6acb48d583..ea759969398 100644
--- a/Sources/Services/AWSECRPUBLIC/Tests/AWSECRPUBLICTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSECRPUBLIC/Tests/AWSECRPUBLICTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSECRPUBLIC
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSECS/Sources/AWSECS/Endpoints.swift b/Sources/Services/AWSECS/Sources/AWSECS/Endpoints.swift
index 60bc97bcad0..4116a7a9ada 100644
--- a/Sources/Services/AWSECS/Sources/AWSECS/Endpoints.swift
+++ b/Sources/Services/AWSECS/Sources/AWSECS/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSECS/Tests/AWSECSTests/EndpointResolverTest.swift b/Sources/Services/AWSECS/Tests/AWSECSTests/EndpointResolverTest.swift
index 2de2e482f80..f628f183dd3 100644
--- a/Sources/Services/AWSECS/Tests/AWSECSTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSECS/Tests/AWSECSTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSECS
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSEFS/Sources/AWSEFS/Endpoints.swift b/Sources/Services/AWSEFS/Sources/AWSEFS/Endpoints.swift
index f511bf2391d..b8af694d7fa 100644
--- a/Sources/Services/AWSEFS/Sources/AWSEFS/Endpoints.swift
+++ b/Sources/Services/AWSEFS/Sources/AWSEFS/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSEFS/Tests/AWSEFSTests/EndpointResolverTest.swift b/Sources/Services/AWSEFS/Tests/AWSEFSTests/EndpointResolverTest.swift
index e5b698d5842..5c89c02cae5 100644
--- a/Sources/Services/AWSEFS/Tests/AWSEFSTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSEFS/Tests/AWSEFSTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSEFS
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -851,7 +852,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -871,7 +872,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -891,7 +892,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -911,7 +912,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -931,7 +932,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -951,7 +952,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -971,7 +972,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -991,7 +992,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1011,7 +1012,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1031,7 +1032,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1051,7 +1052,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1071,7 +1072,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1091,7 +1092,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1111,7 +1112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1131,7 +1132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1151,7 +1152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1171,7 +1172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1191,7 +1192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1211,7 +1212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1269,7 +1270,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1289,7 +1290,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1348,7 +1349,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1368,7 +1369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSEKS/Sources/AWSEKS/Endpoints.swift b/Sources/Services/AWSEKS/Sources/AWSEKS/Endpoints.swift
index 5bfa8eaa4d2..ef46c996a8c 100644
--- a/Sources/Services/AWSEKS/Sources/AWSEKS/Endpoints.swift
+++ b/Sources/Services/AWSEKS/Sources/AWSEKS/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSEKS/Tests/AWSEKSTests/EndpointResolverTest.swift b/Sources/Services/AWSEKS/Tests/AWSEKSTests/EndpointResolverTest.swift
index d0bd21793e3..3c0edbea839 100644
--- a/Sources/Services/AWSEKS/Tests/AWSEKSTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSEKS/Tests/AWSEKSTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSEKS
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -850,7 +851,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -889,7 +890,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSEKSAuth/Sources/AWSEKSAuth/Endpoints.swift b/Sources/Services/AWSEKSAuth/Sources/AWSEKSAuth/Endpoints.swift
index 7fb5b10dae5..53ad5762ff4 100644
--- a/Sources/Services/AWSEKSAuth/Sources/AWSEKSAuth/Endpoints.swift
+++ b/Sources/Services/AWSEKSAuth/Sources/AWSEKSAuth/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSEKSAuth/Tests/AWSEKSAuthTests/EndpointResolverTest.swift b/Sources/Services/AWSEKSAuth/Tests/AWSEKSAuthTests/EndpointResolverTest.swift
index 712d1a3c732..63e436c36dc 100644
--- a/Sources/Services/AWSEKSAuth/Tests/AWSEKSAuthTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSEKSAuth/Tests/AWSEKSAuthTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSEKSAuth
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -49,7 +50,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -68,7 +69,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,7 +88,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -106,7 +107,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -125,7 +126,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -145,7 +146,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -164,7 +165,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSEMR/Sources/AWSEMR/Endpoints.swift b/Sources/Services/AWSEMR/Sources/AWSEMR/Endpoints.swift
index 06c359d9ad3..3b96dfb8b93 100644
--- a/Sources/Services/AWSEMR/Sources/AWSEMR/Endpoints.swift
+++ b/Sources/Services/AWSEMR/Sources/AWSEMR/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSEMR/Tests/AWSEMRTests/EndpointResolverTest.swift b/Sources/Services/AWSEMR/Tests/AWSEMRTests/EndpointResolverTest.swift
index 4a7b1e34a8b..b9b6a5775f0 100644
--- a/Sources/Services/AWSEMR/Tests/AWSEMRTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSEMR/Tests/AWSEMRTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSEMR
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -851,7 +852,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -890,7 +891,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -929,7 +930,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1028,7 +1029,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSEMRServerless/Sources/AWSEMRServerless/Endpoints.swift b/Sources/Services/AWSEMRServerless/Sources/AWSEMRServerless/Endpoints.swift
index 7aeb08d81dd..46783f0aa0c 100644
--- a/Sources/Services/AWSEMRServerless/Sources/AWSEMRServerless/Endpoints.swift
+++ b/Sources/Services/AWSEMRServerless/Sources/AWSEMRServerless/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSEMRServerless/Tests/AWSEMRServerlessTests/EndpointResolverTest.swift b/Sources/Services/AWSEMRServerless/Tests/AWSEMRServerlessTests/EndpointResolverTest.swift
index e433d20f1f0..ebb256b097b 100644
--- a/Sources/Services/AWSEMRServerless/Tests/AWSEMRServerlessTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSEMRServerless/Tests/AWSEMRServerlessTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSEMRServerless
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -370,7 +371,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -409,7 +410,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -487,7 +488,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -508,7 +509,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -528,7 +529,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSEMRcontainers/Sources/AWSEMRcontainers/Endpoints.swift b/Sources/Services/AWSEMRcontainers/Sources/AWSEMRcontainers/Endpoints.swift
index fb3b9f98fa4..8025c6d4ba6 100644
--- a/Sources/Services/AWSEMRcontainers/Sources/AWSEMRcontainers/Endpoints.swift
+++ b/Sources/Services/AWSEMRcontainers/Sources/AWSEMRcontainers/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSEMRcontainers/Tests/AWSEMRcontainersTests/EndpointResolverTest.swift b/Sources/Services/AWSEMRcontainers/Tests/AWSEMRcontainersTests/EndpointResolverTest.swift
index c39a10c5e5f..f7513b18874 100644
--- a/Sources/Services/AWSEMRcontainers/Tests/AWSEMRcontainersTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSEMRcontainers/Tests/AWSEMRcontainersTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSEMRcontainers
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -730,7 +731,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -769,7 +770,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -808,7 +809,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -847,7 +848,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -868,7 +869,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSElastiCache/Sources/AWSElastiCache/Endpoints.swift b/Sources/Services/AWSElastiCache/Sources/AWSElastiCache/Endpoints.swift
index 884c5fa0117..403a509559e 100644
--- a/Sources/Services/AWSElastiCache/Sources/AWSElastiCache/Endpoints.swift
+++ b/Sources/Services/AWSElastiCache/Sources/AWSElastiCache/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSElastiCache/Tests/AWSElastiCacheTests/EndpointResolverTest.swift b/Sources/Services/AWSElastiCache/Tests/AWSElastiCacheTests/EndpointResolverTest.swift
index bcc16cf7552..f7dfacc8c9f 100644
--- a/Sources/Services/AWSElastiCache/Tests/AWSElastiCacheTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSElastiCache/Tests/AWSElastiCacheTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSElastiCache
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSElasticBeanstalk/Sources/AWSElasticBeanstalk/Endpoints.swift b/Sources/Services/AWSElasticBeanstalk/Sources/AWSElasticBeanstalk/Endpoints.swift
index f6b6b46bcc7..01367459ab4 100644
--- a/Sources/Services/AWSElasticBeanstalk/Sources/AWSElasticBeanstalk/Endpoints.swift
+++ b/Sources/Services/AWSElasticBeanstalk/Sources/AWSElasticBeanstalk/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSElasticBeanstalk/Tests/AWSElasticBeanstalkTests/EndpointResolverTest.swift b/Sources/Services/AWSElasticBeanstalk/Tests/AWSElasticBeanstalkTests/EndpointResolverTest.swift
index cba895326ca..ffc40b70ade 100644
--- a/Sources/Services/AWSElasticBeanstalk/Tests/AWSElasticBeanstalkTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSElasticBeanstalk/Tests/AWSElasticBeanstalkTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSElasticBeanstalk
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -830,7 +831,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -869,7 +870,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -947,7 +948,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSElasticLoadBalancing/Sources/AWSElasticLoadBalancing/Endpoints.swift b/Sources/Services/AWSElasticLoadBalancing/Sources/AWSElasticLoadBalancing/Endpoints.swift
index 5bf65d4d982..4ccc6942559 100644
--- a/Sources/Services/AWSElasticLoadBalancing/Sources/AWSElasticLoadBalancing/Endpoints.swift
+++ b/Sources/Services/AWSElasticLoadBalancing/Sources/AWSElasticLoadBalancing/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSElasticLoadBalancing/Tests/AWSElasticLoadBalancingTests/EndpointResolverTest.swift b/Sources/Services/AWSElasticLoadBalancing/Tests/AWSElasticLoadBalancingTests/EndpointResolverTest.swift
index 5ab43fd2009..baaeac209cf 100644
--- a/Sources/Services/AWSElasticLoadBalancing/Tests/AWSElasticLoadBalancingTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSElasticLoadBalancing/Tests/AWSElasticLoadBalancingTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSElasticLoadBalancing
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSElasticLoadBalancingv2/Sources/AWSElasticLoadBalancingv2/Endpoints.swift b/Sources/Services/AWSElasticLoadBalancingv2/Sources/AWSElasticLoadBalancingv2/Endpoints.swift
index 5bf65d4d982..4ccc6942559 100644
--- a/Sources/Services/AWSElasticLoadBalancingv2/Sources/AWSElasticLoadBalancingv2/Endpoints.swift
+++ b/Sources/Services/AWSElasticLoadBalancingv2/Sources/AWSElasticLoadBalancingv2/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSElasticLoadBalancingv2/Tests/AWSElasticLoadBalancingv2Tests/EndpointResolverTest.swift b/Sources/Services/AWSElasticLoadBalancingv2/Tests/AWSElasticLoadBalancingv2Tests/EndpointResolverTest.swift
index efc9dbb2138..af638f7df0b 100644
--- a/Sources/Services/AWSElasticLoadBalancingv2/Tests/AWSElasticLoadBalancingv2Tests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSElasticLoadBalancingv2/Tests/AWSElasticLoadBalancingv2Tests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSElasticLoadBalancingv2
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSElasticTranscoder/Sources/AWSElasticTranscoder/Endpoints.swift b/Sources/Services/AWSElasticTranscoder/Sources/AWSElasticTranscoder/Endpoints.swift
index a1540c0f559..673de6fe65c 100644
--- a/Sources/Services/AWSElasticTranscoder/Sources/AWSElasticTranscoder/Endpoints.swift
+++ b/Sources/Services/AWSElasticTranscoder/Sources/AWSElasticTranscoder/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSElasticTranscoder/Tests/AWSElasticTranscoderTests/EndpointResolverTest.swift b/Sources/Services/AWSElasticTranscoder/Tests/AWSElasticTranscoderTests/EndpointResolverTest.swift
index d2ff1dfa032..4c0c22dc609 100644
--- a/Sources/Services/AWSElasticTranscoder/Tests/AWSElasticTranscoderTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSElasticTranscoder/Tests/AWSElasticTranscoderTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSElasticTranscoder
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -430,7 +431,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -469,7 +470,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -508,7 +509,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -547,7 +548,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -588,7 +589,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSElasticsearchService/Sources/AWSElasticsearchService/Endpoints.swift b/Sources/Services/AWSElasticsearchService/Sources/AWSElasticsearchService/Endpoints.swift
index f303dd48a00..7fd76693fb8 100644
--- a/Sources/Services/AWSElasticsearchService/Sources/AWSElasticsearchService/Endpoints.swift
+++ b/Sources/Services/AWSElasticsearchService/Sources/AWSElasticsearchService/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSElasticsearchService/Tests/AWSElasticsearchServiceTests/EndpointResolverTest.swift b/Sources/Services/AWSElasticsearchService/Tests/AWSElasticsearchServiceTests/EndpointResolverTest.swift
index 53a9a94d035..6e7ca48713f 100644
--- a/Sources/Services/AWSElasticsearchService/Tests/AWSElasticsearchServiceTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSElasticsearchService/Tests/AWSElasticsearchServiceTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSElasticsearchService
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSEntityResolution/Sources/AWSEntityResolution/Endpoints.swift b/Sources/Services/AWSEntityResolution/Sources/AWSEntityResolution/Endpoints.swift
index 59e86ec40fe..2b13909e9c4 100644
--- a/Sources/Services/AWSEntityResolution/Sources/AWSEntityResolution/Endpoints.swift
+++ b/Sources/Services/AWSEntityResolution/Sources/AWSEntityResolution/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSEntityResolution/Tests/AWSEntityResolutionTests/EndpointResolverTest.swift b/Sources/Services/AWSEntityResolution/Tests/AWSEntityResolutionTests/EndpointResolverTest.swift
index cf8cd1ae7bc..92c8766e84f 100644
--- a/Sources/Services/AWSEntityResolution/Tests/AWSEntityResolutionTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSEntityResolution/Tests/AWSEntityResolutionTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSEntityResolution
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSEventBridge/Sources/AWSEventBridge/Endpoints.swift b/Sources/Services/AWSEventBridge/Sources/AWSEventBridge/Endpoints.swift
index ad0c2041529..919468788fa 100644
--- a/Sources/Services/AWSEventBridge/Sources/AWSEventBridge/Endpoints.swift
+++ b/Sources/Services/AWSEventBridge/Sources/AWSEventBridge/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// Operation parameter for EndpointId
diff --git a/Sources/Services/AWSEventBridge/Tests/AWSEventBridgeTests/EndpointResolverTest.swift b/Sources/Services/AWSEventBridge/Tests/AWSEventBridgeTests/EndpointResolverTest.swift
index 8f497c1d8c4..42b6d592c79 100644
--- a/Sources/Services/AWSEventBridge/Tests/AWSEventBridgeTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSEventBridge/Tests/AWSEventBridgeTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSEventBridge
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1085,7 +1086,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1093,9 +1094,9 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4a",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable]
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        ]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1196,7 +1197,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1204,9 +1205,9 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4a",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable]
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        ]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1228,7 +1229,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1236,9 +1237,9 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4a",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable]
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        ]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSEvidently/Sources/AWSEvidently/Endpoints.swift b/Sources/Services/AWSEvidently/Sources/AWSEvidently/Endpoints.swift
index f9c3fdeec40..60d36b5ae1e 100644
--- a/Sources/Services/AWSEvidently/Sources/AWSEvidently/Endpoints.swift
+++ b/Sources/Services/AWSEvidently/Sources/AWSEvidently/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSEvidently/Tests/AWSEvidentlyTests/EndpointResolverTest.swift b/Sources/Services/AWSEvidently/Tests/AWSEvidentlyTests/EndpointResolverTest.swift
index d59ec5d600a..a7e408148e8 100644
--- a/Sources/Services/AWSEvidently/Tests/AWSEvidentlyTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSEvidently/Tests/AWSEvidentlyTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSEvidently
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -450,7 +451,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -489,7 +490,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -528,7 +529,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -567,7 +568,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -588,7 +589,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -608,7 +609,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSFMS/Sources/AWSFMS/Endpoints.swift b/Sources/Services/AWSFMS/Sources/AWSFMS/Endpoints.swift
index c7aaf0945c5..281e9b71cf4 100644
--- a/Sources/Services/AWSFMS/Sources/AWSFMS/Endpoints.swift
+++ b/Sources/Services/AWSFMS/Sources/AWSFMS/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSFMS/Tests/AWSFMSTests/EndpointResolverTest.swift b/Sources/Services/AWSFMS/Tests/AWSFMSTests/EndpointResolverTest.swift
index a40d3ebbce3..8cdaf7c54b2 100644
--- a/Sources/Services/AWSFMS/Tests/AWSFMSTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSFMS/Tests/AWSFMSTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSFMS
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -851,7 +852,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -871,7 +872,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -891,7 +892,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -911,7 +912,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -931,7 +932,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -951,7 +952,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -971,7 +972,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -991,7 +992,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1011,7 +1012,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1031,7 +1032,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1051,7 +1052,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1071,7 +1072,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1110,7 +1111,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1149,7 +1150,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1188,7 +1189,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1227,7 +1228,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1248,7 +1249,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1268,7 +1269,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSFSx/Sources/AWSFSx/Endpoints.swift b/Sources/Services/AWSFSx/Sources/AWSFSx/Endpoints.swift
index b7e2f1c8f5b..ad3050db3e2 100644
--- a/Sources/Services/AWSFSx/Sources/AWSFSx/Endpoints.swift
+++ b/Sources/Services/AWSFSx/Sources/AWSFSx/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSFSx/Tests/AWSFSxTests/EndpointResolverTest.swift b/Sources/Services/AWSFSx/Tests/AWSFSxTests/EndpointResolverTest.swift
index b5b6503a590..d191b1cbdb1 100644
--- a/Sources/Services/AWSFSx/Tests/AWSFSxTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSFSx/Tests/AWSFSxTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSFSx
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -830,7 +831,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -869,7 +870,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -947,7 +948,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSFinspace/Sources/AWSFinspace/Endpoints.swift b/Sources/Services/AWSFinspace/Sources/AWSFinspace/Endpoints.swift
index 17ac7b9fd87..a978277aa3c 100644
--- a/Sources/Services/AWSFinspace/Sources/AWSFinspace/Endpoints.swift
+++ b/Sources/Services/AWSFinspace/Sources/AWSFinspace/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSFinspace/Tests/AWSFinspaceTests/EndpointResolverTest.swift b/Sources/Services/AWSFinspace/Tests/AWSFinspaceTests/EndpointResolverTest.swift
index b0984588c75..91ba0f06a9f 100644
--- a/Sources/Services/AWSFinspace/Tests/AWSFinspaceTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSFinspace/Tests/AWSFinspaceTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSFinspace
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -370,7 +371,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -409,7 +410,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -487,7 +488,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -508,7 +509,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -528,7 +529,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSFinspacedata/Sources/AWSFinspacedata/Endpoints.swift b/Sources/Services/AWSFinspacedata/Sources/AWSFinspacedata/Endpoints.swift
index fa0ad69acf3..86a6129cd84 100644
--- a/Sources/Services/AWSFinspacedata/Sources/AWSFinspacedata/Endpoints.swift
+++ b/Sources/Services/AWSFinspacedata/Sources/AWSFinspacedata/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSFinspacedata/Tests/AWSFinspacedataTests/EndpointResolverTest.swift b/Sources/Services/AWSFinspacedata/Tests/AWSFinspacedataTests/EndpointResolverTest.swift
index 7fa9b1e4d7b..cfcb7368bf6 100644
--- a/Sources/Services/AWSFinspacedata/Tests/AWSFinspacedataTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSFinspacedata/Tests/AWSFinspacedataTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSFinspacedata
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -370,7 +371,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -409,7 +410,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -487,7 +488,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -508,7 +509,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -528,7 +529,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSFirehose/Sources/AWSFirehose/Endpoints.swift b/Sources/Services/AWSFirehose/Sources/AWSFirehose/Endpoints.swift
index 978dd32cfef..5674b168361 100644
--- a/Sources/Services/AWSFirehose/Sources/AWSFirehose/Endpoints.swift
+++ b/Sources/Services/AWSFirehose/Sources/AWSFirehose/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSFirehose/Tests/AWSFirehoseTests/EndpointResolverTest.swift b/Sources/Services/AWSFirehose/Tests/AWSFirehoseTests/EndpointResolverTest.swift
index 927a1f685be..ebbcdb4ddbb 100644
--- a/Sources/Services/AWSFirehose/Tests/AWSFirehoseTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSFirehose/Tests/AWSFirehoseTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSFirehose
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -850,7 +851,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -947,7 +948,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSFis/Sources/AWSFis/Endpoints.swift b/Sources/Services/AWSFis/Sources/AWSFis/Endpoints.swift
index 98d39a45995..5510ceaccb3 100644
--- a/Sources/Services/AWSFis/Sources/AWSFis/Endpoints.swift
+++ b/Sources/Services/AWSFis/Sources/AWSFis/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSFis/Tests/AWSFisTests/EndpointResolverTest.swift b/Sources/Services/AWSFis/Tests/AWSFisTests/EndpointResolverTest.swift
index a34f1fa8886..2b0fd998e54 100644
--- a/Sources/Services/AWSFis/Tests/AWSFisTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSFis/Tests/AWSFisTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSFis
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -330,7 +331,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -369,7 +370,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -408,7 +409,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -447,7 +448,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSForecast/Sources/AWSForecast/Endpoints.swift b/Sources/Services/AWSForecast/Sources/AWSForecast/Endpoints.swift
index 5ea97a2053a..d1faabf7b92 100644
--- a/Sources/Services/AWSForecast/Sources/AWSForecast/Endpoints.swift
+++ b/Sources/Services/AWSForecast/Sources/AWSForecast/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSForecast/Tests/AWSForecastTests/EndpointResolverTest.swift b/Sources/Services/AWSForecast/Tests/AWSForecastTests/EndpointResolverTest.swift
index f711717ec03..16d81dbf220 100644
--- a/Sources/Services/AWSForecast/Tests/AWSForecastTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSForecast/Tests/AWSForecastTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSForecast
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -510,7 +511,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -549,7 +550,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -588,7 +589,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -627,7 +628,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSForecastquery/Sources/AWSForecastquery/Endpoints.swift b/Sources/Services/AWSForecastquery/Sources/AWSForecastquery/Endpoints.swift
index 7ab590ff3a1..5760a3889fb 100644
--- a/Sources/Services/AWSForecastquery/Sources/AWSForecastquery/Endpoints.swift
+++ b/Sources/Services/AWSForecastquery/Sources/AWSForecastquery/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSForecastquery/Tests/AWSForecastqueryTests/EndpointResolverTest.swift b/Sources/Services/AWSForecastquery/Tests/AWSForecastqueryTests/EndpointResolverTest.swift
index 3b8bb9c6a02..8d58e139f04 100644
--- a/Sources/Services/AWSForecastquery/Tests/AWSForecastqueryTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSForecastquery/Tests/AWSForecastqueryTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSForecastquery
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -510,7 +511,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -549,7 +550,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -588,7 +589,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -627,7 +628,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSFraudDetector/Sources/AWSFraudDetector/Endpoints.swift b/Sources/Services/AWSFraudDetector/Sources/AWSFraudDetector/Endpoints.swift
index 4881bbd52f5..b16d5f62093 100644
--- a/Sources/Services/AWSFraudDetector/Sources/AWSFraudDetector/Endpoints.swift
+++ b/Sources/Services/AWSFraudDetector/Sources/AWSFraudDetector/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSFraudDetector/Tests/AWSFraudDetectorTests/EndpointResolverTest.swift b/Sources/Services/AWSFraudDetector/Tests/AWSFraudDetectorTests/EndpointResolverTest.swift
index 3cd3aacd655..184cdb25910 100644
--- a/Sources/Services/AWSFraudDetector/Tests/AWSFraudDetectorTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSFraudDetector/Tests/AWSFraudDetectorTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSFraudDetector
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -390,7 +391,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -429,7 +430,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -507,7 +508,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -528,7 +529,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSFreeTier/Sources/AWSFreeTier/Endpoints.swift b/Sources/Services/AWSFreeTier/Sources/AWSFreeTier/Endpoints.swift
index e0ac8415f57..030635015fd 100644
--- a/Sources/Services/AWSFreeTier/Sources/AWSFreeTier/Endpoints.swift
+++ b/Sources/Services/AWSFreeTier/Sources/AWSFreeTier/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSFreeTier/Tests/AWSFreeTierTests/EndpointResolverTest.swift b/Sources/Services/AWSFreeTier/Tests/AWSFreeTierTests/EndpointResolverTest.swift
index 7970def85d4..7e442b3c9a0 100644
--- a/Sources/Services/AWSFreeTier/Tests/AWSFreeTierTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSFreeTier/Tests/AWSFreeTierTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSFreeTier
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,15 +31,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "freetier",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -57,7 +58,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -76,15 +77,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "freetier",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -103,15 +104,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "freetier",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -130,7 +131,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -149,7 +150,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -168,7 +169,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -187,7 +188,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -207,7 +208,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -226,7 +227,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSGameLift/Sources/AWSGameLift/Endpoints.swift b/Sources/Services/AWSGameLift/Sources/AWSGameLift/Endpoints.swift
index e8d426de6f2..aebfcf44b82 100644
--- a/Sources/Services/AWSGameLift/Sources/AWSGameLift/Endpoints.swift
+++ b/Sources/Services/AWSGameLift/Sources/AWSGameLift/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSGameLift/Tests/AWSGameLiftTests/EndpointResolverTest.swift b/Sources/Services/AWSGameLift/Tests/AWSGameLiftTests/EndpointResolverTest.swift
index 17c75090add..2b299a441ee 100644
--- a/Sources/Services/AWSGameLift/Tests/AWSGameLiftTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSGameLift/Tests/AWSGameLiftTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSGameLift
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -710,7 +711,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -749,7 +750,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -788,7 +789,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -827,7 +828,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -868,7 +869,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSGameLiftStreams/Sources/AWSGameLiftStreams/Endpoints.swift b/Sources/Services/AWSGameLiftStreams/Sources/AWSGameLiftStreams/Endpoints.swift
index b227b026020..72f07cd3bd7 100644
--- a/Sources/Services/AWSGameLiftStreams/Sources/AWSGameLiftStreams/Endpoints.swift
+++ b/Sources/Services/AWSGameLiftStreams/Sources/AWSGameLiftStreams/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSGameLiftStreams/Tests/AWSGameLiftStreamsTests/EndpointResolverTest.swift b/Sources/Services/AWSGameLiftStreams/Tests/AWSGameLiftStreamsTests/EndpointResolverTest.swift
index 3351a2a7d9c..62af8e49856 100644
--- a/Sources/Services/AWSGameLiftStreams/Tests/AWSGameLiftStreamsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSGameLiftStreams/Tests/AWSGameLiftStreamsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSGameLiftStreams
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -67,7 +68,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -86,7 +87,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -105,7 +106,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -124,7 +125,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -143,7 +144,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -162,7 +163,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -181,7 +182,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -200,7 +201,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -219,7 +220,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -238,7 +239,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -257,7 +258,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -276,7 +277,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -295,7 +296,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -314,7 +315,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSGeoMaps/Sources/AWSGeoMaps/Endpoints.swift b/Sources/Services/AWSGeoMaps/Sources/AWSGeoMaps/Endpoints.swift
index 9661d0feb38..5d7ed53a509 100644
--- a/Sources/Services/AWSGeoMaps/Sources/AWSGeoMaps/Endpoints.swift
+++ b/Sources/Services/AWSGeoMaps/Sources/AWSGeoMaps/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSGeoMaps/Tests/AWSGeoMapsTests/EndpointResolverTest.swift b/Sources/Services/AWSGeoMaps/Tests/AWSGeoMapsTests/EndpointResolverTest.swift
index eabb772112d..ea13868b826 100644
--- a/Sources/Services/AWSGeoMaps/Tests/AWSGeoMapsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSGeoMaps/Tests/AWSGeoMapsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSGeoMaps
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,7 +88,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -107,7 +108,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -127,7 +128,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -147,7 +148,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -167,7 +168,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -187,7 +188,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -207,7 +208,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -227,7 +228,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -247,7 +248,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -267,7 +268,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -287,7 +288,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -307,7 +308,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -346,7 +347,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -385,7 +386,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -424,7 +425,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -463,7 +464,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -502,7 +503,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -541,7 +542,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -580,7 +581,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -619,7 +620,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSGeoPlaces/Sources/AWSGeoPlaces/Endpoints.swift b/Sources/Services/AWSGeoPlaces/Sources/AWSGeoPlaces/Endpoints.swift
index 298027d3012..fcba407bb77 100644
--- a/Sources/Services/AWSGeoPlaces/Sources/AWSGeoPlaces/Endpoints.swift
+++ b/Sources/Services/AWSGeoPlaces/Sources/AWSGeoPlaces/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSGeoPlaces/Tests/AWSGeoPlacesTests/EndpointResolverTest.swift b/Sources/Services/AWSGeoPlaces/Tests/AWSGeoPlacesTests/EndpointResolverTest.swift
index e5ceab7713c..06885046ff5 100644
--- a/Sources/Services/AWSGeoPlaces/Tests/AWSGeoPlacesTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSGeoPlaces/Tests/AWSGeoPlacesTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSGeoPlaces
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,7 +88,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -107,7 +108,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -127,7 +128,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -147,7 +148,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -167,7 +168,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -187,7 +188,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -207,7 +208,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -227,7 +228,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -247,7 +248,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -267,7 +268,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -287,7 +288,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -307,7 +308,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -346,7 +347,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -385,7 +386,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -424,7 +425,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -463,7 +464,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -502,7 +503,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -541,7 +542,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -580,7 +581,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -619,7 +620,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSGeoRoutes/Sources/AWSGeoRoutes/Endpoints.swift b/Sources/Services/AWSGeoRoutes/Sources/AWSGeoRoutes/Endpoints.swift
index 767aad9cfe5..48a2152b137 100644
--- a/Sources/Services/AWSGeoRoutes/Sources/AWSGeoRoutes/Endpoints.swift
+++ b/Sources/Services/AWSGeoRoutes/Sources/AWSGeoRoutes/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSGeoRoutes/Tests/AWSGeoRoutesTests/EndpointResolverTest.swift b/Sources/Services/AWSGeoRoutes/Tests/AWSGeoRoutesTests/EndpointResolverTest.swift
index 3bfb73d93d7..1724f490433 100644
--- a/Sources/Services/AWSGeoRoutes/Tests/AWSGeoRoutesTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSGeoRoutes/Tests/AWSGeoRoutesTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSGeoRoutes
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,7 +88,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -107,7 +108,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -127,7 +128,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -147,7 +148,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -167,7 +168,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -187,7 +188,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -207,7 +208,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -227,7 +228,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -247,7 +248,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -267,7 +268,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -287,7 +288,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -307,7 +308,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -346,7 +347,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -385,7 +386,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -424,7 +425,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -463,7 +464,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -502,7 +503,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -541,7 +542,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -580,7 +581,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -619,7 +620,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSGlacier/Sources/AWSGlacier/Endpoints.swift b/Sources/Services/AWSGlacier/Sources/AWSGlacier/Endpoints.swift
index 0c43059cfe9..07d9f9b9285 100644
--- a/Sources/Services/AWSGlacier/Sources/AWSGlacier/Endpoints.swift
+++ b/Sources/Services/AWSGlacier/Sources/AWSGlacier/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSGlacier/Tests/AWSGlacierTests/EndpointResolverTest.swift b/Sources/Services/AWSGlacier/Tests/AWSGlacierTests/EndpointResolverTest.swift
index 5444c32faee..d9736311d84 100644
--- a/Sources/Services/AWSGlacier/Tests/AWSGlacierTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSGlacier/Tests/AWSGlacierTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSGlacier
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -851,7 +852,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -890,7 +891,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -929,7 +930,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1028,7 +1029,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSGlobalAccelerator/Sources/AWSGlobalAccelerator/Endpoints.swift b/Sources/Services/AWSGlobalAccelerator/Sources/AWSGlobalAccelerator/Endpoints.swift
index 0e06c734a2d..a5f34c645c4 100644
--- a/Sources/Services/AWSGlobalAccelerator/Sources/AWSGlobalAccelerator/Endpoints.swift
+++ b/Sources/Services/AWSGlobalAccelerator/Sources/AWSGlobalAccelerator/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSGlobalAccelerator/Tests/AWSGlobalAcceleratorTests/EndpointResolverTest.swift b/Sources/Services/AWSGlobalAccelerator/Tests/AWSGlobalAcceleratorTests/EndpointResolverTest.swift
index 0224a1a457e..766f2f11390 100644
--- a/Sources/Services/AWSGlobalAccelerator/Tests/AWSGlobalAcceleratorTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSGlobalAccelerator/Tests/AWSGlobalAcceleratorTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSGlobalAccelerator
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSGlue/Sources/AWSGlue/Endpoints.swift b/Sources/Services/AWSGlue/Sources/AWSGlue/Endpoints.swift
index 5bce5bce68d..4e8fe0a36f8 100644
--- a/Sources/Services/AWSGlue/Sources/AWSGlue/Endpoints.swift
+++ b/Sources/Services/AWSGlue/Sources/AWSGlue/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSGlue/Tests/AWSGlueTests/EndpointResolverTest.swift b/Sources/Services/AWSGlue/Tests/AWSGlueTests/EndpointResolverTest.swift
index 8c31dfde365..fa8d3b833c8 100644
--- a/Sources/Services/AWSGlue/Tests/AWSGlueTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSGlue/Tests/AWSGlueTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSGlue
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -810,7 +811,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -849,7 +850,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -927,7 +928,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSGrafana/Sources/AWSGrafana/Endpoints.swift b/Sources/Services/AWSGrafana/Sources/AWSGrafana/Endpoints.swift
index a4417d8bb36..68923d77ed2 100644
--- a/Sources/Services/AWSGrafana/Sources/AWSGrafana/Endpoints.swift
+++ b/Sources/Services/AWSGrafana/Sources/AWSGrafana/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSGrafana/Tests/AWSGrafanaTests/EndpointResolverTest.swift b/Sources/Services/AWSGrafana/Tests/AWSGrafanaTests/EndpointResolverTest.swift
index c206a4911b1..bbe05cddd05 100644
--- a/Sources/Services/AWSGrafana/Tests/AWSGrafanaTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSGrafana/Tests/AWSGrafanaTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSGrafana
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -470,7 +471,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -509,7 +510,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -587,7 +588,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -608,7 +609,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSGreengrass/Sources/AWSGreengrass/Endpoints.swift b/Sources/Services/AWSGreengrass/Sources/AWSGreengrass/Endpoints.swift
index 34f00852196..2ca9d8454d3 100644
--- a/Sources/Services/AWSGreengrass/Sources/AWSGreengrass/Endpoints.swift
+++ b/Sources/Services/AWSGreengrass/Sources/AWSGreengrass/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSGreengrass/Tests/AWSGreengrassTests/EndpointResolverTest.swift b/Sources/Services/AWSGreengrass/Tests/AWSGreengrassTests/EndpointResolverTest.swift
index bf75c2e81a1..87b5456f84f 100644
--- a/Sources/Services/AWSGreengrass/Tests/AWSGreengrassTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSGreengrass/Tests/AWSGreengrassTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSGreengrass
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,15 +412,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "greengrass",
                         "signingRegion": "us-gov-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -439,15 +440,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "greengrass",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -467,7 +468,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -487,7 +488,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -507,7 +508,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -527,7 +528,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -547,7 +548,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -567,7 +568,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -606,7 +607,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -645,7 +646,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -684,7 +685,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -723,7 +724,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -744,7 +745,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -764,7 +765,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSGreengrassV2/Sources/AWSGreengrassV2/Endpoints.swift b/Sources/Services/AWSGreengrassV2/Sources/AWSGreengrassV2/Endpoints.swift
index 34f00852196..2ca9d8454d3 100644
--- a/Sources/Services/AWSGreengrassV2/Sources/AWSGreengrassV2/Endpoints.swift
+++ b/Sources/Services/AWSGreengrassV2/Sources/AWSGreengrassV2/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSGreengrassV2/Tests/AWSGreengrassV2Tests/EndpointResolverTest.swift b/Sources/Services/AWSGreengrassV2/Tests/AWSGreengrassV2Tests/EndpointResolverTest.swift
index 3b1bad24ae5..cebf8ea49b4 100644
--- a/Sources/Services/AWSGreengrassV2/Tests/AWSGreengrassV2Tests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSGreengrassV2/Tests/AWSGreengrassV2Tests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSGreengrassV2
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,15 +412,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "greengrass",
                         "signingRegion": "us-gov-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -439,15 +440,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "greengrass",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -467,7 +468,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -487,7 +488,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -507,7 +508,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -527,7 +528,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -547,7 +548,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -567,7 +568,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -606,7 +607,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -645,7 +646,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -684,7 +685,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -723,7 +724,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -744,7 +745,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -764,7 +765,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSGroundStation/Sources/AWSGroundStation/Endpoints.swift b/Sources/Services/AWSGroundStation/Sources/AWSGroundStation/Endpoints.swift
index 0e814c9ec89..9383e4bc1b4 100644
--- a/Sources/Services/AWSGroundStation/Sources/AWSGroundStation/Endpoints.swift
+++ b/Sources/Services/AWSGroundStation/Sources/AWSGroundStation/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSGroundStation/Tests/AWSGroundStationTests/EndpointResolverTest.swift b/Sources/Services/AWSGroundStation/Tests/AWSGroundStationTests/EndpointResolverTest.swift
index 251e9bc2867..c7585adba5d 100644
--- a/Sources/Services/AWSGroundStation/Tests/AWSGroundStationTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSGroundStation/Tests/AWSGroundStationTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSGroundStation
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -530,7 +531,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -569,7 +570,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -608,7 +609,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -647,7 +648,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -688,7 +689,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSGuardDuty/Sources/AWSGuardDuty/Endpoints.swift b/Sources/Services/AWSGuardDuty/Sources/AWSGuardDuty/Endpoints.swift
index 46fe8b9bd26..2f17ad48693 100644
--- a/Sources/Services/AWSGuardDuty/Sources/AWSGuardDuty/Endpoints.swift
+++ b/Sources/Services/AWSGuardDuty/Sources/AWSGuardDuty/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSGuardDuty/Tests/AWSGuardDutyTests/EndpointResolverTest.swift b/Sources/Services/AWSGuardDuty/Tests/AWSGuardDutyTests/EndpointResolverTest.swift
index e7bda6ec7b4..0d4bc5e3603 100644
--- a/Sources/Services/AWSGuardDuty/Tests/AWSGuardDutyTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSGuardDuty/Tests/AWSGuardDutyTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSGuardDuty
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -830,7 +831,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -869,7 +870,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -947,7 +948,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSHealth/Sources/AWSHealth/Endpoints.swift b/Sources/Services/AWSHealth/Sources/AWSHealth/Endpoints.swift
index d8ceca773eb..5e484592fad 100644
--- a/Sources/Services/AWSHealth/Sources/AWSHealth/Endpoints.swift
+++ b/Sources/Services/AWSHealth/Sources/AWSHealth/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSHealth/Tests/AWSHealthTests/EndpointResolverTest.swift b/Sources/Services/AWSHealth/Tests/AWSHealthTests/EndpointResolverTest.swift
index a98d6797646..b8021e8ec4d 100644
--- a/Sources/Services/AWSHealth/Tests/AWSHealthTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSHealth/Tests/AWSHealthTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSHealth
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,15 +32,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "health",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -59,7 +60,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -79,7 +80,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -99,7 +100,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -119,7 +120,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -139,15 +140,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "health",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -167,7 +168,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -187,7 +188,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -207,7 +208,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -227,7 +228,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -247,7 +248,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -267,7 +268,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -287,7 +288,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -307,7 +308,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -327,7 +328,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -366,7 +367,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -405,7 +406,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -444,7 +445,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -484,7 +485,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -504,7 +505,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSHealthLake/Sources/AWSHealthLake/Endpoints.swift b/Sources/Services/AWSHealthLake/Sources/AWSHealthLake/Endpoints.swift
index cb3afabf604..3ea71e039ee 100644
--- a/Sources/Services/AWSHealthLake/Sources/AWSHealthLake/Endpoints.swift
+++ b/Sources/Services/AWSHealthLake/Sources/AWSHealthLake/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSHealthLake/Tests/AWSHealthLakeTests/EndpointResolverTest.swift b/Sources/Services/AWSHealthLake/Tests/AWSHealthLakeTests/EndpointResolverTest.swift
index 2d631011e4c..370a74ab2fd 100644
--- a/Sources/Services/AWSHealthLake/Tests/AWSHealthLakeTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSHealthLake/Tests/AWSHealthLakeTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSHealthLake
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -330,7 +331,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -369,7 +370,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -408,7 +409,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -447,7 +448,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSIAM/Sources/AWSIAM/Endpoints.swift b/Sources/Services/AWSIAM/Sources/AWSIAM/Endpoints.swift
index e248036b6c5..67ea8e6d45c 100644
--- a/Sources/Services/AWSIAM/Sources/AWSIAM/Endpoints.swift
+++ b/Sources/Services/AWSIAM/Sources/AWSIAM/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSIAM/Tests/AWSIAMTests/EndpointResolverTest.swift b/Sources/Services/AWSIAM/Tests/AWSIAMTests/EndpointResolverTest.swift
index 60fea13e144..e3b9216f32f 100644
--- a/Sources/Services/AWSIAM/Tests/AWSIAMTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSIAM/Tests/AWSIAMTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSIAM
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,14 +88,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -114,14 +115,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -141,14 +142,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -168,14 +169,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -195,14 +196,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -222,14 +223,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -249,14 +250,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-north-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -276,14 +277,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-north-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -303,14 +304,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -330,14 +331,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -357,14 +358,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -384,14 +385,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -430,14 +431,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -476,14 +477,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -522,14 +523,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,14 +569,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -614,14 +615,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -660,14 +661,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -706,14 +707,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -752,14 +753,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSIVSRealTime/Sources/AWSIVSRealTime/Endpoints.swift b/Sources/Services/AWSIVSRealTime/Sources/AWSIVSRealTime/Endpoints.swift
index 9f8a080cf5a..59abe6eae07 100644
--- a/Sources/Services/AWSIVSRealTime/Sources/AWSIVSRealTime/Endpoints.swift
+++ b/Sources/Services/AWSIVSRealTime/Sources/AWSIVSRealTime/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSIVSRealTime/Tests/AWSIVSRealTimeTests/EndpointResolverTest.swift b/Sources/Services/AWSIVSRealTime/Tests/AWSIVSRealTimeTests/EndpointResolverTest.swift
index f709cf37d1c..30f464a1662 100644
--- a/Sources/Services/AWSIVSRealTime/Tests/AWSIVSRealTimeTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSIVSRealTime/Tests/AWSIVSRealTimeTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSIVSRealTime
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSIdentitystore/Sources/AWSIdentitystore/Endpoints.swift b/Sources/Services/AWSIdentitystore/Sources/AWSIdentitystore/Endpoints.swift
index 1162e2e80b6..b893a29e4a3 100644
--- a/Sources/Services/AWSIdentitystore/Sources/AWSIdentitystore/Endpoints.swift
+++ b/Sources/Services/AWSIdentitystore/Sources/AWSIdentitystore/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSIdentitystore/Tests/AWSIdentitystoreTests/EndpointResolverTest.swift b/Sources/Services/AWSIdentitystore/Tests/AWSIdentitystoreTests/EndpointResolverTest.swift
index 00ad107bdaa..b375ed24787 100644
--- a/Sources/Services/AWSIdentitystore/Tests/AWSIdentitystoreTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSIdentitystore/Tests/AWSIdentitystoreTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSIdentitystore
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -570,7 +571,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -609,7 +610,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -687,7 +688,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -708,7 +709,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSImagebuilder/Sources/AWSImagebuilder/Endpoints.swift b/Sources/Services/AWSImagebuilder/Sources/AWSImagebuilder/Endpoints.swift
index 763cf6647ea..a1755078436 100644
--- a/Sources/Services/AWSImagebuilder/Sources/AWSImagebuilder/Endpoints.swift
+++ b/Sources/Services/AWSImagebuilder/Sources/AWSImagebuilder/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSImagebuilder/Tests/AWSImagebuilderTests/EndpointResolverTest.swift b/Sources/Services/AWSImagebuilder/Tests/AWSImagebuilderTests/EndpointResolverTest.swift
index 33beb8f549f..a20405f33a5 100644
--- a/Sources/Services/AWSImagebuilder/Tests/AWSImagebuilderTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSImagebuilder/Tests/AWSImagebuilderTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSImagebuilder
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -330,7 +331,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -369,7 +370,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -408,7 +409,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -447,7 +448,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSInspector/Sources/AWSInspector/Endpoints.swift b/Sources/Services/AWSInspector/Sources/AWSInspector/Endpoints.swift
index c5acf38c044..de892e0d890 100644
--- a/Sources/Services/AWSInspector/Sources/AWSInspector/Endpoints.swift
+++ b/Sources/Services/AWSInspector/Sources/AWSInspector/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSInspector/Tests/AWSInspectorTests/EndpointResolverTest.swift b/Sources/Services/AWSInspector/Tests/AWSInspectorTests/EndpointResolverTest.swift
index ea197a8ba1c..374a665c605 100644
--- a/Sources/Services/AWSInspector/Tests/AWSInspectorTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSInspector/Tests/AWSInspectorTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSInspector
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -610,7 +611,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -649,7 +650,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -688,7 +689,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -727,7 +728,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -768,7 +769,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSInspector2/Sources/AWSInspector2/Endpoints.swift b/Sources/Services/AWSInspector2/Sources/AWSInspector2/Endpoints.swift
index feeeb718ced..883562e8c3a 100644
--- a/Sources/Services/AWSInspector2/Sources/AWSInspector2/Endpoints.swift
+++ b/Sources/Services/AWSInspector2/Sources/AWSInspector2/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSInspector2/Tests/AWSInspector2Tests/EndpointResolverTest.swift b/Sources/Services/AWSInspector2/Tests/AWSInspector2Tests/EndpointResolverTest.swift
index 184e7d28f51..e734891d61b 100644
--- a/Sources/Services/AWSInspector2/Tests/AWSInspector2Tests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSInspector2/Tests/AWSInspector2Tests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSInspector2
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -650,7 +651,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -689,7 +690,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -767,7 +768,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -788,7 +789,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -808,7 +809,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSInspectorScan/Sources/AWSInspectorScan/Endpoints.swift b/Sources/Services/AWSInspectorScan/Sources/AWSInspectorScan/Endpoints.swift
index 1bf2fcaec5c..739e0a4671f 100644
--- a/Sources/Services/AWSInspectorScan/Sources/AWSInspectorScan/Endpoints.swift
+++ b/Sources/Services/AWSInspectorScan/Sources/AWSInspectorScan/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSInspectorScan/Tests/AWSInspectorScanTests/EndpointResolverTest.swift b/Sources/Services/AWSInspectorScan/Tests/AWSInspectorScanTests/EndpointResolverTest.swift
index db28cf0b280..72b484697d2 100644
--- a/Sources/Services/AWSInspectorScan/Tests/AWSInspectorScanTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSInspectorScan/Tests/AWSInspectorScanTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSInspectorScan
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSInternetMonitor/Sources/AWSInternetMonitor/Endpoints.swift b/Sources/Services/AWSInternetMonitor/Sources/AWSInternetMonitor/Endpoints.swift
index 4117a24d6df..bfabe72b687 100644
--- a/Sources/Services/AWSInternetMonitor/Sources/AWSInternetMonitor/Endpoints.swift
+++ b/Sources/Services/AWSInternetMonitor/Sources/AWSInternetMonitor/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSInternetMonitor/Tests/AWSInternetMonitorTests/EndpointResolverTest.swift b/Sources/Services/AWSInternetMonitor/Tests/AWSInternetMonitorTests/EndpointResolverTest.swift
index c79b9b9b15d..9f6f0931750 100644
--- a/Sources/Services/AWSInternetMonitor/Tests/AWSInternetMonitorTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSInternetMonitor/Tests/AWSInternetMonitorTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSInternetMonitor
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSInvoicing/Sources/AWSInvoicing/Endpoints.swift b/Sources/Services/AWSInvoicing/Sources/AWSInvoicing/Endpoints.swift
index 6b66b560756..82f5b2b737e 100644
--- a/Sources/Services/AWSInvoicing/Sources/AWSInvoicing/Endpoints.swift
+++ b/Sources/Services/AWSInvoicing/Sources/AWSInvoicing/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSInvoicing/Tests/AWSInvoicingTests/EndpointResolverTest.swift b/Sources/Services/AWSInvoicing/Tests/AWSInvoicingTests/EndpointResolverTest.swift
index e3953c814cd..eb1da8db557 100644
--- a/Sources/Services/AWSInvoicing/Tests/AWSInvoicingTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSInvoicing/Tests/AWSInvoicingTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSInvoicing
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -67,14 +68,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -93,14 +94,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -119,14 +120,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -145,14 +146,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,14 +172,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -197,14 +198,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -223,14 +224,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -249,14 +250,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -275,14 +276,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -301,14 +302,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -327,14 +328,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -353,14 +354,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -379,14 +380,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -405,14 +406,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSIoT/Sources/AWSIoT/Endpoints.swift b/Sources/Services/AWSIoT/Sources/AWSIoT/Endpoints.swift
index 2c342b9c67e..7f1a5a100b5 100644
--- a/Sources/Services/AWSIoT/Sources/AWSIoT/Endpoints.swift
+++ b/Sources/Services/AWSIoT/Sources/AWSIoT/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSIoT/Tests/AWSIoTTests/EndpointResolverTest.swift b/Sources/Services/AWSIoT/Tests/AWSIoTTests/EndpointResolverTest.swift
index ab6dd47b103..a943710983c 100644
--- a/Sources/Services/AWSIoT/Tests/AWSIoTTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSIoT/Tests/AWSIoTTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSIoT
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -770,7 +771,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -809,7 +810,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -887,7 +888,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSIoTAnalytics/Sources/AWSIoTAnalytics/Endpoints.swift b/Sources/Services/AWSIoTAnalytics/Sources/AWSIoTAnalytics/Endpoints.swift
index e8d81905130..a749e25589d 100644
--- a/Sources/Services/AWSIoTAnalytics/Sources/AWSIoTAnalytics/Endpoints.swift
+++ b/Sources/Services/AWSIoTAnalytics/Sources/AWSIoTAnalytics/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSIoTAnalytics/Tests/AWSIoTAnalyticsTests/EndpointResolverTest.swift b/Sources/Services/AWSIoTAnalytics/Tests/AWSIoTAnalyticsTests/EndpointResolverTest.swift
index 433c32e965a..21d551ea7d3 100644
--- a/Sources/Services/AWSIoTAnalytics/Tests/AWSIoTAnalyticsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSIoTAnalytics/Tests/AWSIoTAnalyticsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSIoTAnalytics
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -430,7 +431,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -469,7 +470,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -508,7 +509,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -547,7 +548,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -588,7 +589,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSIoTDataPlane/Sources/AWSIoTDataPlane/Endpoints.swift b/Sources/Services/AWSIoTDataPlane/Sources/AWSIoTDataPlane/Endpoints.swift
index 8cd9455c75f..d983423c3d1 100644
--- a/Sources/Services/AWSIoTDataPlane/Sources/AWSIoTDataPlane/Endpoints.swift
+++ b/Sources/Services/AWSIoTDataPlane/Sources/AWSIoTDataPlane/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSIoTDataPlane/Tests/AWSIoTDataPlaneTests/EndpointResolverTest.swift b/Sources/Services/AWSIoTDataPlane/Tests/AWSIoTDataPlaneTests/EndpointResolverTest.swift
index a54f7a9b664..2a55ca4fd18 100644
--- a/Sources/Services/AWSIoTDataPlane/Tests/AWSIoTDataPlaneTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSIoTDataPlane/Tests/AWSIoTDataPlaneTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSIoTDataPlane
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -770,7 +771,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -809,7 +810,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -887,7 +888,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSIoTEvents/Sources/AWSIoTEvents/Endpoints.swift b/Sources/Services/AWSIoTEvents/Sources/AWSIoTEvents/Endpoints.swift
index 86a94d8d714..02e81f4e958 100644
--- a/Sources/Services/AWSIoTEvents/Sources/AWSIoTEvents/Endpoints.swift
+++ b/Sources/Services/AWSIoTEvents/Sources/AWSIoTEvents/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSIoTEvents/Tests/AWSIoTEventsTests/EndpointResolverTest.swift b/Sources/Services/AWSIoTEvents/Tests/AWSIoTEventsTests/EndpointResolverTest.swift
index 35c75e457d6..561cd474216 100644
--- a/Sources/Services/AWSIoTEvents/Tests/AWSIoTEventsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSIoTEvents/Tests/AWSIoTEventsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSIoTEvents
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -530,7 +531,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -569,7 +570,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -608,7 +609,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -647,7 +648,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -688,7 +689,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSIoTEventsData/Sources/AWSIoTEventsData/Endpoints.swift b/Sources/Services/AWSIoTEventsData/Sources/AWSIoTEventsData/Endpoints.swift
index 09a8465c987..17cc8b97e91 100644
--- a/Sources/Services/AWSIoTEventsData/Sources/AWSIoTEventsData/Endpoints.swift
+++ b/Sources/Services/AWSIoTEventsData/Sources/AWSIoTEventsData/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSIoTEventsData/Tests/AWSIoTEventsDataTests/EndpointResolverTest.swift b/Sources/Services/AWSIoTEventsData/Tests/AWSIoTEventsDataTests/EndpointResolverTest.swift
index 9d5e8f990ac..9722432a3b8 100644
--- a/Sources/Services/AWSIoTEventsData/Tests/AWSIoTEventsDataTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSIoTEventsData/Tests/AWSIoTEventsDataTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSIoTEventsData
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSIoTFleetHub/Sources/AWSIoTFleetHub/Endpoints.swift b/Sources/Services/AWSIoTFleetHub/Sources/AWSIoTFleetHub/Endpoints.swift
index fc5c3bf7325..9b6e47639d0 100644
--- a/Sources/Services/AWSIoTFleetHub/Sources/AWSIoTFleetHub/Endpoints.swift
+++ b/Sources/Services/AWSIoTFleetHub/Sources/AWSIoTFleetHub/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSIoTFleetHub/Tests/AWSIoTFleetHubTests/EndpointResolverTest.swift b/Sources/Services/AWSIoTFleetHub/Tests/AWSIoTFleetHubTests/EndpointResolverTest.swift
index bc51dcf0967..599709877b9 100644
--- a/Sources/Services/AWSIoTFleetHub/Tests/AWSIoTFleetHubTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSIoTFleetHub/Tests/AWSIoTFleetHubTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSIoTFleetHub
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -590,7 +591,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -629,7 +630,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -707,7 +708,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSIoTFleetWise/Sources/AWSIoTFleetWise/Endpoints.swift b/Sources/Services/AWSIoTFleetWise/Sources/AWSIoTFleetWise/Endpoints.swift
index 079b91412d3..aba9111d15f 100644
--- a/Sources/Services/AWSIoTFleetWise/Sources/AWSIoTFleetWise/Endpoints.swift
+++ b/Sources/Services/AWSIoTFleetWise/Sources/AWSIoTFleetWise/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSIoTFleetWise/Tests/AWSIoTFleetWiseTests/EndpointResolverTest.swift b/Sources/Services/AWSIoTFleetWise/Tests/AWSIoTFleetWiseTests/EndpointResolverTest.swift
index 5f7c41ec6b5..f0d2c8efca5 100644
--- a/Sources/Services/AWSIoTFleetWise/Tests/AWSIoTFleetWiseTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSIoTFleetWise/Tests/AWSIoTFleetWiseTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSIoTFleetWise
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -310,7 +311,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -349,7 +350,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -388,7 +389,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -427,7 +428,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSIoTJobsDataPlane/Sources/AWSIoTJobsDataPlane/Endpoints.swift b/Sources/Services/AWSIoTJobsDataPlane/Sources/AWSIoTJobsDataPlane/Endpoints.swift
index fc463836cfe..baf67be95d2 100644
--- a/Sources/Services/AWSIoTJobsDataPlane/Sources/AWSIoTJobsDataPlane/Endpoints.swift
+++ b/Sources/Services/AWSIoTJobsDataPlane/Sources/AWSIoTJobsDataPlane/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSIoTJobsDataPlane/Tests/AWSIoTJobsDataPlaneTests/EndpointResolverTest.swift b/Sources/Services/AWSIoTJobsDataPlane/Tests/AWSIoTJobsDataPlaneTests/EndpointResolverTest.swift
index 496b995c69a..c6df6725d9b 100644
--- a/Sources/Services/AWSIoTJobsDataPlane/Tests/AWSIoTJobsDataPlaneTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSIoTJobsDataPlane/Tests/AWSIoTJobsDataPlaneTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSIoTJobsDataPlane
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -770,7 +771,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -809,7 +810,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -887,7 +888,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSIoTManagedIntegrations/Sources/AWSIoTManagedIntegrations/Endpoints.swift b/Sources/Services/AWSIoTManagedIntegrations/Sources/AWSIoTManagedIntegrations/Endpoints.swift
index 7dd6b544f7d..227c78cc00e 100644
--- a/Sources/Services/AWSIoTManagedIntegrations/Sources/AWSIoTManagedIntegrations/Endpoints.swift
+++ b/Sources/Services/AWSIoTManagedIntegrations/Sources/AWSIoTManagedIntegrations/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSIoTManagedIntegrations/Tests/AWSIoTManagedIntegrationsTests/EndpointResolverTest.swift b/Sources/Services/AWSIoTManagedIntegrations/Tests/AWSIoTManagedIntegrationsTests/EndpointResolverTest.swift
index 648cd350ea4..86e8958ab66 100644
--- a/Sources/Services/AWSIoTManagedIntegrations/Tests/AWSIoTManagedIntegrationsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSIoTManagedIntegrations/Tests/AWSIoTManagedIntegrationsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSIoTManagedIntegrations
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -67,7 +68,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -86,7 +87,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -105,7 +106,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -124,7 +125,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -143,7 +144,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -162,7 +163,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -181,7 +182,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -200,7 +201,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -219,7 +220,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -238,7 +239,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -257,7 +258,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -276,7 +277,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -295,7 +296,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -314,7 +315,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSIoTSecureTunneling/Sources/AWSIoTSecureTunneling/Endpoints.swift b/Sources/Services/AWSIoTSecureTunneling/Sources/AWSIoTSecureTunneling/Endpoints.swift
index 8660244634e..4efa4d38537 100644
--- a/Sources/Services/AWSIoTSecureTunneling/Sources/AWSIoTSecureTunneling/Endpoints.swift
+++ b/Sources/Services/AWSIoTSecureTunneling/Sources/AWSIoTSecureTunneling/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSIoTSecureTunneling/Tests/AWSIoTSecureTunnelingTests/EndpointResolverTest.swift b/Sources/Services/AWSIoTSecureTunneling/Tests/AWSIoTSecureTunnelingTests/EndpointResolverTest.swift
index 37213485dea..e5971b4ebec 100644
--- a/Sources/Services/AWSIoTSecureTunneling/Tests/AWSIoTSecureTunnelingTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSIoTSecureTunneling/Tests/AWSIoTSecureTunnelingTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSIoTSecureTunneling
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -851,7 +852,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -871,7 +872,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -891,7 +892,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -911,7 +912,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -931,7 +932,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -951,7 +952,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -971,7 +972,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -991,7 +992,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1011,7 +1012,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1031,7 +1032,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1051,7 +1052,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1071,7 +1072,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1091,7 +1092,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1111,7 +1112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1131,7 +1132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1151,7 +1152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1171,7 +1172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1191,7 +1192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1211,7 +1212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1231,7 +1232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1251,7 +1252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1271,7 +1272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1291,7 +1292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1349,7 +1350,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1369,7 +1370,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1428,7 +1429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1448,7 +1449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSIoTSiteWise/Sources/AWSIoTSiteWise/Endpoints.swift b/Sources/Services/AWSIoTSiteWise/Sources/AWSIoTSiteWise/Endpoints.swift
index b80b310540b..54a22478254 100644
--- a/Sources/Services/AWSIoTSiteWise/Sources/AWSIoTSiteWise/Endpoints.swift
+++ b/Sources/Services/AWSIoTSiteWise/Sources/AWSIoTSiteWise/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSIoTSiteWise/Tests/AWSIoTSiteWiseTests/EndpointResolverTest.swift b/Sources/Services/AWSIoTSiteWise/Tests/AWSIoTSiteWiseTests/EndpointResolverTest.swift
index 5a85097a62d..8996fd8d2e5 100644
--- a/Sources/Services/AWSIoTSiteWise/Tests/AWSIoTSiteWiseTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSIoTSiteWise/Tests/AWSIoTSiteWiseTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSIoTSiteWise
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -590,7 +591,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -629,7 +630,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -707,7 +708,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSIoTThingsGraph/Sources/AWSIoTThingsGraph/Endpoints.swift b/Sources/Services/AWSIoTThingsGraph/Sources/AWSIoTThingsGraph/Endpoints.swift
index 487b6ad4a03..1e008820737 100644
--- a/Sources/Services/AWSIoTThingsGraph/Sources/AWSIoTThingsGraph/Endpoints.swift
+++ b/Sources/Services/AWSIoTThingsGraph/Sources/AWSIoTThingsGraph/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSIoTThingsGraph/Tests/AWSIoTThingsGraphTests/EndpointResolverTest.swift b/Sources/Services/AWSIoTThingsGraph/Tests/AWSIoTThingsGraphTests/EndpointResolverTest.swift
index c25831496a1..33dde564b7a 100644
--- a/Sources/Services/AWSIoTThingsGraph/Tests/AWSIoTThingsGraphTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSIoTThingsGraph/Tests/AWSIoTThingsGraphTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSIoTThingsGraph
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -390,7 +391,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -429,7 +430,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -507,7 +508,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -528,7 +529,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSIoTTwinMaker/Sources/AWSIoTTwinMaker/Endpoints.swift b/Sources/Services/AWSIoTTwinMaker/Sources/AWSIoTTwinMaker/Endpoints.swift
index dd4a818a58e..c8be961f536 100644
--- a/Sources/Services/AWSIoTTwinMaker/Sources/AWSIoTTwinMaker/Endpoints.swift
+++ b/Sources/Services/AWSIoTTwinMaker/Sources/AWSIoTTwinMaker/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSIoTTwinMaker/Tests/AWSIoTTwinMakerTests/EndpointResolverTest.swift b/Sources/Services/AWSIoTTwinMaker/Tests/AWSIoTTwinMakerTests/EndpointResolverTest.swift
index e50e6c2d9fe..c64fada6041 100644
--- a/Sources/Services/AWSIoTTwinMaker/Tests/AWSIoTTwinMakerTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSIoTTwinMaker/Tests/AWSIoTTwinMakerTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSIoTTwinMaker
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -390,7 +391,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -429,7 +430,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -507,7 +508,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -528,7 +529,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSIoTWireless/Sources/AWSIoTWireless/Endpoints.swift b/Sources/Services/AWSIoTWireless/Sources/AWSIoTWireless/Endpoints.swift
index 8f10d8f59ac..c2dd7deee32 100644
--- a/Sources/Services/AWSIoTWireless/Sources/AWSIoTWireless/Endpoints.swift
+++ b/Sources/Services/AWSIoTWireless/Sources/AWSIoTWireless/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSIoTWireless/Tests/AWSIoTWirelessTests/EndpointResolverTest.swift b/Sources/Services/AWSIoTWireless/Tests/AWSIoTWirelessTests/EndpointResolverTest.swift
index a12ee2ceb13..4d74d60068b 100644
--- a/Sources/Services/AWSIoTWireless/Tests/AWSIoTWirelessTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSIoTWireless/Tests/AWSIoTWirelessTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSIoTWireless
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -370,7 +371,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -409,7 +410,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -487,7 +488,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -508,7 +509,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -528,7 +529,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSIotDeviceAdvisor/Sources/AWSIotDeviceAdvisor/Endpoints.swift b/Sources/Services/AWSIotDeviceAdvisor/Sources/AWSIotDeviceAdvisor/Endpoints.swift
index 5ccdd2e98cb..cf9c4fa1345 100644
--- a/Sources/Services/AWSIotDeviceAdvisor/Sources/AWSIotDeviceAdvisor/Endpoints.swift
+++ b/Sources/Services/AWSIotDeviceAdvisor/Sources/AWSIotDeviceAdvisor/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSIotDeviceAdvisor/Tests/AWSIotDeviceAdvisorTests/EndpointResolverTest.swift b/Sources/Services/AWSIotDeviceAdvisor/Tests/AWSIotDeviceAdvisorTests/EndpointResolverTest.swift
index a16c733bb09..669badccd7d 100644
--- a/Sources/Services/AWSIotDeviceAdvisor/Tests/AWSIotDeviceAdvisorTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSIotDeviceAdvisor/Tests/AWSIotDeviceAdvisorTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSIotDeviceAdvisor
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -350,7 +351,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -389,7 +390,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -467,7 +468,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -508,7 +509,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSIvs/Sources/AWSIvs/Endpoints.swift b/Sources/Services/AWSIvs/Sources/AWSIvs/Endpoints.swift
index c25ab38286d..54b39d54982 100644
--- a/Sources/Services/AWSIvs/Sources/AWSIvs/Endpoints.swift
+++ b/Sources/Services/AWSIvs/Sources/AWSIvs/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSIvs/Tests/AWSIvsTests/EndpointResolverTest.swift b/Sources/Services/AWSIvs/Tests/AWSIvsTests/EndpointResolverTest.swift
index 90be84e01f1..4389965f1bd 100644
--- a/Sources/Services/AWSIvs/Tests/AWSIvsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSIvs/Tests/AWSIvsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSIvs
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -410,7 +411,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -449,7 +450,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -527,7 +528,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSIvschat/Sources/AWSIvschat/Endpoints.swift b/Sources/Services/AWSIvschat/Sources/AWSIvschat/Endpoints.swift
index b70b2081956..66999af6d18 100644
--- a/Sources/Services/AWSIvschat/Sources/AWSIvschat/Endpoints.swift
+++ b/Sources/Services/AWSIvschat/Sources/AWSIvschat/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSIvschat/Tests/AWSIvschatTests/EndpointResolverTest.swift b/Sources/Services/AWSIvschat/Tests/AWSIvschatTests/EndpointResolverTest.swift
index c8cb3513f9c..4554101a418 100644
--- a/Sources/Services/AWSIvschat/Tests/AWSIvschatTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSIvschat/Tests/AWSIvschatTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSIvschat
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -330,7 +331,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -369,7 +370,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -408,7 +409,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -447,7 +448,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSKMS/Sources/AWSKMS/Endpoints.swift b/Sources/Services/AWSKMS/Sources/AWSKMS/Endpoints.swift
index 273e3a3a20b..1ba863451a3 100644
--- a/Sources/Services/AWSKMS/Sources/AWSKMS/Endpoints.swift
+++ b/Sources/Services/AWSKMS/Sources/AWSKMS/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSKMS/Tests/AWSKMSTests/EndpointResolverTest.swift b/Sources/Services/AWSKMS/Tests/AWSKMSTests/EndpointResolverTest.swift
index e33e4df628b..79b8de6c1c4 100644
--- a/Sources/Services/AWSKMS/Tests/AWSKMSTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSKMS/Tests/AWSKMSTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSKMS
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -851,7 +852,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -871,7 +872,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -891,7 +892,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -911,7 +912,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -931,7 +932,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -951,7 +952,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -971,7 +972,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -991,7 +992,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1011,7 +1012,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1031,7 +1032,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1051,7 +1052,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1071,7 +1072,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1091,7 +1092,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1111,7 +1112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1131,7 +1132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1151,7 +1152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1171,7 +1172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1191,7 +1192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1211,7 +1212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1231,7 +1232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1289,7 +1290,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1309,7 +1310,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1368,7 +1369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1388,7 +1389,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSKafka/Sources/AWSKafka/Endpoints.swift b/Sources/Services/AWSKafka/Sources/AWSKafka/Endpoints.swift
index a450f120bf9..a11a589e4f3 100644
--- a/Sources/Services/AWSKafka/Sources/AWSKafka/Endpoints.swift
+++ b/Sources/Services/AWSKafka/Sources/AWSKafka/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSKafka/Tests/AWSKafkaTests/EndpointResolverTest.swift b/Sources/Services/AWSKafka/Tests/AWSKafkaTests/EndpointResolverTest.swift
index efb6ea26d0a..0c193d0423e 100644
--- a/Sources/Services/AWSKafka/Tests/AWSKafkaTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSKafka/Tests/AWSKafkaTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSKafka
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -750,7 +751,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -789,7 +790,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -828,7 +829,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -867,7 +868,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSKafkaConnect/Sources/AWSKafkaConnect/Endpoints.swift b/Sources/Services/AWSKafkaConnect/Sources/AWSKafkaConnect/Endpoints.swift
index 4dbb2aa4988..c40b1b9947a 100644
--- a/Sources/Services/AWSKafkaConnect/Sources/AWSKafkaConnect/Endpoints.swift
+++ b/Sources/Services/AWSKafkaConnect/Sources/AWSKafkaConnect/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSKafkaConnect/Tests/AWSKafkaConnectTests/EndpointResolverTest.swift b/Sources/Services/AWSKafkaConnect/Tests/AWSKafkaConnectTests/EndpointResolverTest.swift
index d39f09f30c5..39d2cbabbe9 100644
--- a/Sources/Services/AWSKafkaConnect/Tests/AWSKafkaConnectTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSKafkaConnect/Tests/AWSKafkaConnectTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSKafkaConnect
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -590,7 +591,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -629,7 +630,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -707,7 +708,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSKendra/Sources/AWSKendra/Endpoints.swift b/Sources/Services/AWSKendra/Sources/AWSKendra/Endpoints.swift
index 664ebb3d26b..819d12bfb58 100644
--- a/Sources/Services/AWSKendra/Sources/AWSKendra/Endpoints.swift
+++ b/Sources/Services/AWSKendra/Sources/AWSKendra/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSKendra/Tests/AWSKendraTests/EndpointResolverTest.swift b/Sources/Services/AWSKendra/Tests/AWSKendraTests/EndpointResolverTest.swift
index cadb88ae104..70ce316b9ba 100644
--- a/Sources/Services/AWSKendra/Tests/AWSKendraTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSKendra/Tests/AWSKendraTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSKendra
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -490,7 +491,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -529,7 +530,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -607,7 +608,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSKendraRanking/Sources/AWSKendraRanking/Endpoints.swift b/Sources/Services/AWSKendraRanking/Sources/AWSKendraRanking/Endpoints.swift
index 7e55cd200ed..4c5f787c116 100644
--- a/Sources/Services/AWSKendraRanking/Sources/AWSKendraRanking/Endpoints.swift
+++ b/Sources/Services/AWSKendraRanking/Sources/AWSKendraRanking/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSKendraRanking/Tests/AWSKendraRankingTests/EndpointResolverTest.swift b/Sources/Services/AWSKendraRanking/Tests/AWSKendraRankingTests/EndpointResolverTest.swift
index 7f5a11dc703..a1c2471eb61 100644
--- a/Sources/Services/AWSKendraRanking/Tests/AWSKendraRankingTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSKendraRanking/Tests/AWSKendraRankingTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSKendraRanking
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -49,7 +50,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -68,7 +69,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,7 +88,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -106,7 +107,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -125,7 +126,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -145,7 +146,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -164,7 +165,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSKeyspaces/Sources/AWSKeyspaces/Endpoints.swift b/Sources/Services/AWSKeyspaces/Sources/AWSKeyspaces/Endpoints.swift
index 99d0a01578f..5be6d220bcd 100644
--- a/Sources/Services/AWSKeyspaces/Sources/AWSKeyspaces/Endpoints.swift
+++ b/Sources/Services/AWSKeyspaces/Sources/AWSKeyspaces/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSKeyspaces/Tests/AWSKeyspacesTests/EndpointResolverTest.swift b/Sources/Services/AWSKeyspaces/Tests/AWSKeyspacesTests/EndpointResolverTest.swift
index 651dba9c196..419aa9cf214 100644
--- a/Sources/Services/AWSKeyspaces/Tests/AWSKeyspacesTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSKeyspaces/Tests/AWSKeyspacesTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSKeyspaces
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -690,7 +691,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -729,7 +730,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -768,7 +769,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -807,7 +808,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -828,7 +829,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSKinesis/Sources/AWSKinesis/Endpoints.swift b/Sources/Services/AWSKinesis/Sources/AWSKinesis/Endpoints.swift
index f9aa96830e4..0ffec819f6a 100644
--- a/Sources/Services/AWSKinesis/Sources/AWSKinesis/Endpoints.swift
+++ b/Sources/Services/AWSKinesis/Sources/AWSKinesis/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// The ARN of the Kinesis consumer
     public let consumerARN: Swift.String?
     /// Override the endpoint used to send this request
diff --git a/Sources/Services/AWSKinesis/Tests/AWSKinesisTests/EndpointResolverTest.swift b/Sources/Services/AWSKinesis/Tests/AWSKinesisTests/EndpointResolverTest.swift
index f8c53004c52..2bbafbb3f61 100644
--- a/Sources/Services/AWSKinesis/Tests/AWSKinesisTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSKinesis/Tests/AWSKinesisTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSKinesis
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1310,7 +1311,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1332,7 +1333,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1354,7 +1355,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1376,7 +1377,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1398,7 +1399,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1420,7 +1421,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1442,7 +1443,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1464,7 +1465,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1486,7 +1487,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1508,7 +1509,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1530,7 +1531,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1552,7 +1553,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1574,7 +1575,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1596,7 +1597,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1618,7 +1619,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1640,7 +1641,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1886,7 +1887,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1908,7 +1909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1930,7 +1931,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1952,7 +1953,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1974,7 +1975,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1996,7 +1997,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2018,7 +2019,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2040,7 +2041,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2062,7 +2063,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2084,7 +2085,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2106,7 +2107,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2128,7 +2129,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2150,7 +2151,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2172,7 +2173,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2194,7 +2195,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2216,7 +2217,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2238,7 +2239,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2261,7 +2262,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2507,7 +2508,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2529,7 +2530,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2551,7 +2552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2573,7 +2574,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2595,7 +2596,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2617,7 +2618,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2639,7 +2640,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2661,7 +2662,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2683,7 +2684,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2705,7 +2706,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2727,7 +2728,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2749,7 +2750,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2771,7 +2772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2793,7 +2794,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2815,7 +2816,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2837,7 +2838,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3063,7 +3064,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3085,7 +3086,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3107,7 +3108,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3129,7 +3130,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3151,7 +3152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3173,7 +3174,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3195,7 +3196,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3217,7 +3218,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3239,7 +3240,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3261,7 +3262,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3283,7 +3284,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3305,7 +3306,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3327,7 +3328,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3349,7 +3350,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3371,7 +3372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3393,7 +3394,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSKinesisAnalytics/Sources/AWSKinesisAnalytics/Endpoints.swift b/Sources/Services/AWSKinesisAnalytics/Sources/AWSKinesisAnalytics/Endpoints.swift
index bcb7f229e04..45dce6e6e35 100644
--- a/Sources/Services/AWSKinesisAnalytics/Sources/AWSKinesisAnalytics/Endpoints.swift
+++ b/Sources/Services/AWSKinesisAnalytics/Sources/AWSKinesisAnalytics/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSKinesisAnalytics/Tests/AWSKinesisAnalyticsTests/EndpointResolverTest.swift b/Sources/Services/AWSKinesisAnalytics/Tests/AWSKinesisAnalyticsTests/EndpointResolverTest.swift
index 6328c123e26..aba4fe120cd 100644
--- a/Sources/Services/AWSKinesisAnalytics/Tests/AWSKinesisAnalyticsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSKinesisAnalytics/Tests/AWSKinesisAnalyticsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSKinesisAnalytics
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -730,7 +731,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -769,7 +770,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -808,7 +809,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -847,7 +848,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -868,7 +869,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSKinesisAnalyticsV2/Sources/AWSKinesisAnalyticsV2/Endpoints.swift b/Sources/Services/AWSKinesisAnalyticsV2/Sources/AWSKinesisAnalyticsV2/Endpoints.swift
index bcb7f229e04..45dce6e6e35 100644
--- a/Sources/Services/AWSKinesisAnalyticsV2/Sources/AWSKinesisAnalyticsV2/Endpoints.swift
+++ b/Sources/Services/AWSKinesisAnalyticsV2/Sources/AWSKinesisAnalyticsV2/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSKinesisAnalyticsV2/Tests/AWSKinesisAnalyticsV2Tests/EndpointResolverTest.swift b/Sources/Services/AWSKinesisAnalyticsV2/Tests/AWSKinesisAnalyticsV2Tests/EndpointResolverTest.swift
index ea13837c6a1..6ce50d18178 100644
--- a/Sources/Services/AWSKinesisAnalyticsV2/Tests/AWSKinesisAnalyticsV2Tests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSKinesisAnalyticsV2/Tests/AWSKinesisAnalyticsV2Tests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSKinesisAnalyticsV2
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -730,7 +731,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -769,7 +770,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -808,7 +809,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -847,7 +848,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -868,7 +869,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSKinesisVideo/Sources/AWSKinesisVideo/Endpoints.swift b/Sources/Services/AWSKinesisVideo/Sources/AWSKinesisVideo/Endpoints.swift
index 9d3167b3c69..171854bbb7d 100644
--- a/Sources/Services/AWSKinesisVideo/Sources/AWSKinesisVideo/Endpoints.swift
+++ b/Sources/Services/AWSKinesisVideo/Sources/AWSKinesisVideo/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSKinesisVideo/Tests/AWSKinesisVideoTests/EndpointResolverTest.swift b/Sources/Services/AWSKinesisVideo/Tests/AWSKinesisVideoTests/EndpointResolverTest.swift
index dc60c31744a..ebb85b8603d 100644
--- a/Sources/Services/AWSKinesisVideo/Tests/AWSKinesisVideoTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSKinesisVideo/Tests/AWSKinesisVideoTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSKinesisVideo
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -590,7 +591,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -629,7 +630,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -707,7 +708,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSKinesisVideoArchivedMedia/Sources/AWSKinesisVideoArchivedMedia/Endpoints.swift b/Sources/Services/AWSKinesisVideoArchivedMedia/Sources/AWSKinesisVideoArchivedMedia/Endpoints.swift
index 9d3167b3c69..171854bbb7d 100644
--- a/Sources/Services/AWSKinesisVideoArchivedMedia/Sources/AWSKinesisVideoArchivedMedia/Endpoints.swift
+++ b/Sources/Services/AWSKinesisVideoArchivedMedia/Sources/AWSKinesisVideoArchivedMedia/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSKinesisVideoArchivedMedia/Tests/AWSKinesisVideoArchivedMediaTests/EndpointResolverTest.swift b/Sources/Services/AWSKinesisVideoArchivedMedia/Tests/AWSKinesisVideoArchivedMediaTests/EndpointResolverTest.swift
index 9076a36e7de..1298537f3e3 100644
--- a/Sources/Services/AWSKinesisVideoArchivedMedia/Tests/AWSKinesisVideoArchivedMediaTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSKinesisVideoArchivedMedia/Tests/AWSKinesisVideoArchivedMediaTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSKinesisVideoArchivedMedia
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -590,7 +591,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -629,7 +630,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -707,7 +708,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSKinesisVideoMedia/Sources/AWSKinesisVideoMedia/Endpoints.swift b/Sources/Services/AWSKinesisVideoMedia/Sources/AWSKinesisVideoMedia/Endpoints.swift
index 9d3167b3c69..171854bbb7d 100644
--- a/Sources/Services/AWSKinesisVideoMedia/Sources/AWSKinesisVideoMedia/Endpoints.swift
+++ b/Sources/Services/AWSKinesisVideoMedia/Sources/AWSKinesisVideoMedia/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSKinesisVideoMedia/Tests/AWSKinesisVideoMediaTests/EndpointResolverTest.swift b/Sources/Services/AWSKinesisVideoMedia/Tests/AWSKinesisVideoMediaTests/EndpointResolverTest.swift
index 18e4eaa95b7..f4954776b3b 100644
--- a/Sources/Services/AWSKinesisVideoMedia/Tests/AWSKinesisVideoMediaTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSKinesisVideoMedia/Tests/AWSKinesisVideoMediaTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSKinesisVideoMedia
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -590,7 +591,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -629,7 +630,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -707,7 +708,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSKinesisVideoSignaling/Sources/AWSKinesisVideoSignaling/Endpoints.swift b/Sources/Services/AWSKinesisVideoSignaling/Sources/AWSKinesisVideoSignaling/Endpoints.swift
index 9d3167b3c69..171854bbb7d 100644
--- a/Sources/Services/AWSKinesisVideoSignaling/Sources/AWSKinesisVideoSignaling/Endpoints.swift
+++ b/Sources/Services/AWSKinesisVideoSignaling/Sources/AWSKinesisVideoSignaling/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSKinesisVideoSignaling/Tests/AWSKinesisVideoSignalingTests/EndpointResolverTest.swift b/Sources/Services/AWSKinesisVideoSignaling/Tests/AWSKinesisVideoSignalingTests/EndpointResolverTest.swift
index 3f169afcda0..77cd6af0530 100644
--- a/Sources/Services/AWSKinesisVideoSignaling/Tests/AWSKinesisVideoSignalingTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSKinesisVideoSignaling/Tests/AWSKinesisVideoSignalingTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSKinesisVideoSignaling
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -590,7 +591,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -629,7 +630,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -707,7 +708,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSKinesisVideoWebRTCStorage/Sources/AWSKinesisVideoWebRTCStorage/Endpoints.swift b/Sources/Services/AWSKinesisVideoWebRTCStorage/Sources/AWSKinesisVideoWebRTCStorage/Endpoints.swift
index 476ce244481..2d380959b13 100644
--- a/Sources/Services/AWSKinesisVideoWebRTCStorage/Sources/AWSKinesisVideoWebRTCStorage/Endpoints.swift
+++ b/Sources/Services/AWSKinesisVideoWebRTCStorage/Sources/AWSKinesisVideoWebRTCStorage/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSKinesisVideoWebRTCStorage/Tests/AWSKinesisVideoWebRTCStorageTests/EndpointResolverTest.swift b/Sources/Services/AWSKinesisVideoWebRTCStorage/Tests/AWSKinesisVideoWebRTCStorageTests/EndpointResolverTest.swift
index dacdcacf312..145711edcdb 100644
--- a/Sources/Services/AWSKinesisVideoWebRTCStorage/Tests/AWSKinesisVideoWebRTCStorageTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSKinesisVideoWebRTCStorage/Tests/AWSKinesisVideoWebRTCStorageTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSKinesisVideoWebRTCStorage
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSLakeFormation/Sources/AWSLakeFormation/Endpoints.swift b/Sources/Services/AWSLakeFormation/Sources/AWSLakeFormation/Endpoints.swift
index 7174dbc88d2..a931fd7912e 100644
--- a/Sources/Services/AWSLakeFormation/Sources/AWSLakeFormation/Endpoints.swift
+++ b/Sources/Services/AWSLakeFormation/Sources/AWSLakeFormation/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSLakeFormation/Tests/AWSLakeFormationTests/EndpointResolverTest.swift b/Sources/Services/AWSLakeFormation/Tests/AWSLakeFormationTests/EndpointResolverTest.swift
index 0d1349d3377..91e1a007bcd 100644
--- a/Sources/Services/AWSLakeFormation/Tests/AWSLakeFormationTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSLakeFormation/Tests/AWSLakeFormationTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSLakeFormation
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -810,7 +811,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -849,7 +850,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -927,7 +928,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSLambda/Sources/AWSLambda/Endpoints.swift b/Sources/Services/AWSLambda/Sources/AWSLambda/Endpoints.swift
index 64e79733307..225bc3808ee 100644
--- a/Sources/Services/AWSLambda/Sources/AWSLambda/Endpoints.swift
+++ b/Sources/Services/AWSLambda/Sources/AWSLambda/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSLambda/Tests/AWSLambdaTests/EndpointResolverTest.swift b/Sources/Services/AWSLambda/Tests/AWSLambdaTests/EndpointResolverTest.swift
index 5d5209440ef..906e2503963 100644
--- a/Sources/Services/AWSLambda/Tests/AWSLambdaTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSLambda/Tests/AWSLambdaTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSLambda
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -851,7 +852,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -871,7 +872,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -891,7 +892,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -911,7 +912,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -931,7 +932,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -951,7 +952,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -971,7 +972,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -991,7 +992,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1011,7 +1012,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1031,7 +1032,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1051,7 +1052,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1071,7 +1072,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1091,7 +1092,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1111,7 +1112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1131,7 +1132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1151,7 +1152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1171,7 +1172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1191,7 +1192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1211,7 +1212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1231,7 +1232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1251,7 +1252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1271,7 +1272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1310,7 +1311,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1349,7 +1350,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1388,7 +1389,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1428,7 +1429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1448,7 +1449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSLaunchWizard/Sources/AWSLaunchWizard/Endpoints.swift b/Sources/Services/AWSLaunchWizard/Sources/AWSLaunchWizard/Endpoints.swift
index f7a991bd562..8756dd19757 100644
--- a/Sources/Services/AWSLaunchWizard/Sources/AWSLaunchWizard/Endpoints.swift
+++ b/Sources/Services/AWSLaunchWizard/Sources/AWSLaunchWizard/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSLaunchWizard/Tests/AWSLaunchWizardTests/EndpointResolverTest.swift b/Sources/Services/AWSLaunchWizard/Tests/AWSLaunchWizardTests/EndpointResolverTest.swift
index 2966c1f8bd7..22e9bb007b9 100644
--- a/Sources/Services/AWSLaunchWizard/Tests/AWSLaunchWizardTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSLaunchWizard/Tests/AWSLaunchWizardTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSLaunchWizard
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSLexModelBuildingService/Sources/AWSLexModelBuildingService/Endpoints.swift b/Sources/Services/AWSLexModelBuildingService/Sources/AWSLexModelBuildingService/Endpoints.swift
index 8ddcedc7def..98eb09e02e0 100644
--- a/Sources/Services/AWSLexModelBuildingService/Sources/AWSLexModelBuildingService/Endpoints.swift
+++ b/Sources/Services/AWSLexModelBuildingService/Sources/AWSLexModelBuildingService/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSLexModelBuildingService/Tests/AWSLexModelBuildingServiceTests/EndpointResolverTest.swift b/Sources/Services/AWSLexModelBuildingService/Tests/AWSLexModelBuildingServiceTests/EndpointResolverTest.swift
index eb178cc38e4..8d18ddb9f5b 100644
--- a/Sources/Services/AWSLexModelBuildingService/Tests/AWSLexModelBuildingServiceTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSLexModelBuildingService/Tests/AWSLexModelBuildingServiceTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSLexModelBuildingService
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -490,7 +491,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -529,7 +530,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -607,7 +608,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSLexModelsV2/Sources/AWSLexModelsV2/Endpoints.swift b/Sources/Services/AWSLexModelsV2/Sources/AWSLexModelsV2/Endpoints.swift
index b134ec1db89..2f631dc1ce1 100644
--- a/Sources/Services/AWSLexModelsV2/Sources/AWSLexModelsV2/Endpoints.swift
+++ b/Sources/Services/AWSLexModelsV2/Sources/AWSLexModelsV2/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSLexModelsV2/Tests/AWSLexModelsV2Tests/EndpointResolverTest.swift b/Sources/Services/AWSLexModelsV2/Tests/AWSLexModelsV2Tests/EndpointResolverTest.swift
index 7af41d00d9c..9c3a23d4514 100644
--- a/Sources/Services/AWSLexModelsV2/Tests/AWSLexModelsV2Tests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSLexModelsV2/Tests/AWSLexModelsV2Tests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSLexModelsV2
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -490,7 +491,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -529,7 +530,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -607,7 +608,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSLexRuntimeService/Sources/AWSLexRuntimeService/Endpoints.swift b/Sources/Services/AWSLexRuntimeService/Sources/AWSLexRuntimeService/Endpoints.swift
index 0c357e1377d..99c9d4eeb32 100644
--- a/Sources/Services/AWSLexRuntimeService/Sources/AWSLexRuntimeService/Endpoints.swift
+++ b/Sources/Services/AWSLexRuntimeService/Sources/AWSLexRuntimeService/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSLexRuntimeService/Tests/AWSLexRuntimeServiceTests/EndpointResolverTest.swift b/Sources/Services/AWSLexRuntimeService/Tests/AWSLexRuntimeServiceTests/EndpointResolverTest.swift
index f154a1a3d0f..d0a837476a9 100644
--- a/Sources/Services/AWSLexRuntimeService/Tests/AWSLexRuntimeServiceTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSLexRuntimeService/Tests/AWSLexRuntimeServiceTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSLexRuntimeService
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -490,7 +491,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -529,7 +530,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -607,7 +608,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSLexRuntimeV2/Sources/AWSLexRuntimeV2/Endpoints.swift b/Sources/Services/AWSLexRuntimeV2/Sources/AWSLexRuntimeV2/Endpoints.swift
index 3fe77349616..f7910eb3d30 100644
--- a/Sources/Services/AWSLexRuntimeV2/Sources/AWSLexRuntimeV2/Endpoints.swift
+++ b/Sources/Services/AWSLexRuntimeV2/Sources/AWSLexRuntimeV2/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSLexRuntimeV2/Tests/AWSLexRuntimeV2Tests/EndpointResolverTest.swift b/Sources/Services/AWSLexRuntimeV2/Tests/AWSLexRuntimeV2Tests/EndpointResolverTest.swift
index d11cefe2737..cd7875ac730 100644
--- a/Sources/Services/AWSLexRuntimeV2/Tests/AWSLexRuntimeV2Tests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSLexRuntimeV2/Tests/AWSLexRuntimeV2Tests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSLexRuntimeV2
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -490,7 +491,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -529,7 +530,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -607,7 +608,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSLicenseManager/Sources/AWSLicenseManager/Endpoints.swift b/Sources/Services/AWSLicenseManager/Sources/AWSLicenseManager/Endpoints.swift
index f783bc3d53d..8a5844546dc 100644
--- a/Sources/Services/AWSLicenseManager/Sources/AWSLicenseManager/Endpoints.swift
+++ b/Sources/Services/AWSLicenseManager/Sources/AWSLicenseManager/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSLicenseManager/Tests/AWSLicenseManagerTests/EndpointResolverTest.swift b/Sources/Services/AWSLicenseManager/Tests/AWSLicenseManagerTests/EndpointResolverTest.swift
index 6e0591ac651..4954beccc48 100644
--- a/Sources/Services/AWSLicenseManager/Tests/AWSLicenseManagerTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSLicenseManager/Tests/AWSLicenseManagerTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSLicenseManager
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -850,7 +851,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -889,7 +890,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSLicenseManagerLinuxSubscriptions/Sources/AWSLicenseManagerLinuxSubscriptions/Endpoints.swift b/Sources/Services/AWSLicenseManagerLinuxSubscriptions/Sources/AWSLicenseManagerLinuxSubscriptions/Endpoints.swift
index 01b09cf7032..b0aef653333 100644
--- a/Sources/Services/AWSLicenseManagerLinuxSubscriptions/Sources/AWSLicenseManagerLinuxSubscriptions/Endpoints.swift
+++ b/Sources/Services/AWSLicenseManagerLinuxSubscriptions/Sources/AWSLicenseManagerLinuxSubscriptions/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSLicenseManagerLinuxSubscriptions/Tests/AWSLicenseManagerLinuxSubscriptionsTests/EndpointResolverTest.swift b/Sources/Services/AWSLicenseManagerLinuxSubscriptions/Tests/AWSLicenseManagerLinuxSubscriptionsTests/EndpointResolverTest.swift
index b9170202d96..676cc740d8a 100644
--- a/Sources/Services/AWSLicenseManagerLinuxSubscriptions/Tests/AWSLicenseManagerLinuxSubscriptionsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSLicenseManagerLinuxSubscriptions/Tests/AWSLicenseManagerLinuxSubscriptionsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSLicenseManagerLinuxSubscriptions
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSLicenseManagerUserSubscriptions/Sources/AWSLicenseManagerUserSubscriptions/Endpoints.swift b/Sources/Services/AWSLicenseManagerUserSubscriptions/Sources/AWSLicenseManagerUserSubscriptions/Endpoints.swift
index 4789c26f052..bae3639550b 100644
--- a/Sources/Services/AWSLicenseManagerUserSubscriptions/Sources/AWSLicenseManagerUserSubscriptions/Endpoints.swift
+++ b/Sources/Services/AWSLicenseManagerUserSubscriptions/Sources/AWSLicenseManagerUserSubscriptions/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSLicenseManagerUserSubscriptions/Tests/AWSLicenseManagerUserSubscriptionsTests/EndpointResolverTest.swift b/Sources/Services/AWSLicenseManagerUserSubscriptions/Tests/AWSLicenseManagerUserSubscriptionsTests/EndpointResolverTest.swift
index c5c0a9f8e5a..c7f7663b282 100644
--- a/Sources/Services/AWSLicenseManagerUserSubscriptions/Tests/AWSLicenseManagerUserSubscriptionsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSLicenseManagerUserSubscriptions/Tests/AWSLicenseManagerUserSubscriptionsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSLicenseManagerUserSubscriptions
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSLightsail/Sources/AWSLightsail/Endpoints.swift b/Sources/Services/AWSLightsail/Sources/AWSLightsail/Endpoints.swift
index 3ff690671d2..7083b501a88 100644
--- a/Sources/Services/AWSLightsail/Sources/AWSLightsail/Endpoints.swift
+++ b/Sources/Services/AWSLightsail/Sources/AWSLightsail/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSLightsail/Tests/AWSLightsailTests/EndpointResolverTest.swift b/Sources/Services/AWSLightsail/Tests/AWSLightsailTests/EndpointResolverTest.swift
index f44bb6e0e67..31b7936e059 100644
--- a/Sources/Services/AWSLightsail/Tests/AWSLightsailTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSLightsail/Tests/AWSLightsailTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSLightsail
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -550,7 +551,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -589,7 +590,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -667,7 +668,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -688,7 +689,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -708,7 +709,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSLocation/Sources/AWSLocation/Endpoints.swift b/Sources/Services/AWSLocation/Sources/AWSLocation/Endpoints.swift
index 56c9a5fee39..e2bc40645da 100644
--- a/Sources/Services/AWSLocation/Sources/AWSLocation/Endpoints.swift
+++ b/Sources/Services/AWSLocation/Sources/AWSLocation/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSLocation/Tests/AWSLocationTests/EndpointResolverTest.swift b/Sources/Services/AWSLocation/Tests/AWSLocationTests/EndpointResolverTest.swift
index d89fa9e2d81..bf23661c9dc 100644
--- a/Sources/Services/AWSLocation/Tests/AWSLocationTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSLocation/Tests/AWSLocationTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSLocation
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSLookoutEquipment/Sources/AWSLookoutEquipment/Endpoints.swift b/Sources/Services/AWSLookoutEquipment/Sources/AWSLookoutEquipment/Endpoints.swift
index 825290cd3ba..19410cf9c6b 100644
--- a/Sources/Services/AWSLookoutEquipment/Sources/AWSLookoutEquipment/Endpoints.swift
+++ b/Sources/Services/AWSLookoutEquipment/Sources/AWSLookoutEquipment/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSLookoutEquipment/Tests/AWSLookoutEquipmentTests/EndpointResolverTest.swift b/Sources/Services/AWSLookoutEquipment/Tests/AWSLookoutEquipmentTests/EndpointResolverTest.swift
index 4101687aa37..1d6f83c12df 100644
--- a/Sources/Services/AWSLookoutEquipment/Tests/AWSLookoutEquipmentTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSLookoutEquipment/Tests/AWSLookoutEquipmentTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSLookoutEquipment
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -330,7 +331,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -369,7 +370,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -408,7 +409,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -447,7 +448,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSLookoutMetrics/Sources/AWSLookoutMetrics/Endpoints.swift b/Sources/Services/AWSLookoutMetrics/Sources/AWSLookoutMetrics/Endpoints.swift
index 588cc0b757f..d1531d41442 100644
--- a/Sources/Services/AWSLookoutMetrics/Sources/AWSLookoutMetrics/Endpoints.swift
+++ b/Sources/Services/AWSLookoutMetrics/Sources/AWSLookoutMetrics/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSLookoutMetrics/Tests/AWSLookoutMetricsTests/EndpointResolverTest.swift b/Sources/Services/AWSLookoutMetrics/Tests/AWSLookoutMetricsTests/EndpointResolverTest.swift
index ceb65ed2cbf..d5b2040c11d 100644
--- a/Sources/Services/AWSLookoutMetrics/Tests/AWSLookoutMetricsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSLookoutMetrics/Tests/AWSLookoutMetricsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSLookoutMetrics
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -450,7 +451,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -489,7 +490,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -528,7 +529,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -567,7 +568,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -588,7 +589,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -608,7 +609,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSLookoutVision/Sources/AWSLookoutVision/Endpoints.swift b/Sources/Services/AWSLookoutVision/Sources/AWSLookoutVision/Endpoints.swift
index 4cd6a3e8d61..82fdb308694 100644
--- a/Sources/Services/AWSLookoutVision/Sources/AWSLookoutVision/Endpoints.swift
+++ b/Sources/Services/AWSLookoutVision/Sources/AWSLookoutVision/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSLookoutVision/Tests/AWSLookoutVisionTests/EndpointResolverTest.swift b/Sources/Services/AWSLookoutVision/Tests/AWSLookoutVisionTests/EndpointResolverTest.swift
index b02786972a3..d2a7a78da99 100644
--- a/Sources/Services/AWSLookoutVision/Tests/AWSLookoutVisionTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSLookoutVision/Tests/AWSLookoutVisionTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSLookoutVision
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -410,7 +411,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -449,7 +450,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -527,7 +528,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSM2/Sources/AWSM2/Endpoints.swift b/Sources/Services/AWSM2/Sources/AWSM2/Endpoints.swift
index df9d55d6cf7..a80f2051338 100644
--- a/Sources/Services/AWSM2/Sources/AWSM2/Endpoints.swift
+++ b/Sources/Services/AWSM2/Sources/AWSM2/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSM2/Tests/AWSM2Tests/EndpointResolverTest.swift b/Sources/Services/AWSM2/Tests/AWSM2Tests/EndpointResolverTest.swift
index 34611af2024..b53d213f952 100644
--- a/Sources/Services/AWSM2/Tests/AWSM2Tests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSM2/Tests/AWSM2Tests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSM2
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -410,7 +411,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -449,7 +450,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -527,7 +528,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMTurk/Sources/AWSMTurk/Endpoints.swift b/Sources/Services/AWSMTurk/Sources/AWSMTurk/Endpoints.swift
index 5c721c43e03..aa5374ac2ab 100644
--- a/Sources/Services/AWSMTurk/Sources/AWSMTurk/Endpoints.swift
+++ b/Sources/Services/AWSMTurk/Sources/AWSMTurk/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMTurk/Tests/AWSMTurkTests/EndpointResolverTest.swift b/Sources/Services/AWSMTurk/Tests/AWSMTurkTests/EndpointResolverTest.swift
index ea5503849a8..eb68a445b8d 100644
--- a/Sources/Services/AWSMTurk/Tests/AWSMTurkTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMTurk/Tests/AWSMTurkTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMTurk
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -310,7 +311,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -349,7 +350,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -388,7 +389,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -427,7 +428,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMWAA/Sources/AWSMWAA/Endpoints.swift b/Sources/Services/AWSMWAA/Sources/AWSMWAA/Endpoints.swift
index 5772b6b5278..dacd895c54e 100644
--- a/Sources/Services/AWSMWAA/Sources/AWSMWAA/Endpoints.swift
+++ b/Sources/Services/AWSMWAA/Sources/AWSMWAA/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMWAA/Tests/AWSMWAATests/EndpointResolverTest.swift b/Sources/Services/AWSMWAA/Tests/AWSMWAATests/EndpointResolverTest.swift
index 8ea5705dde2..b82e5d537df 100644
--- a/Sources/Services/AWSMWAA/Tests/AWSMWAATests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMWAA/Tests/AWSMWAATests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMWAA
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -570,7 +571,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -609,7 +610,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -687,7 +688,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -708,7 +709,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMachineLearning/Sources/AWSMachineLearning/Endpoints.swift b/Sources/Services/AWSMachineLearning/Sources/AWSMachineLearning/Endpoints.swift
index b4be539b487..b43734ec007 100644
--- a/Sources/Services/AWSMachineLearning/Sources/AWSMachineLearning/Endpoints.swift
+++ b/Sources/Services/AWSMachineLearning/Sources/AWSMachineLearning/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMachineLearning/Tests/AWSMachineLearningTests/EndpointResolverTest.swift b/Sources/Services/AWSMachineLearning/Tests/AWSMachineLearningTests/EndpointResolverTest.swift
index 078b6c2f062..06aeafc8716 100644
--- a/Sources/Services/AWSMachineLearning/Tests/AWSMachineLearningTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMachineLearning/Tests/AWSMachineLearningTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMachineLearning
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -310,7 +311,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -349,7 +350,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -388,7 +389,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -427,7 +428,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMacie2/Sources/AWSMacie2/Endpoints.swift b/Sources/Services/AWSMacie2/Sources/AWSMacie2/Endpoints.swift
index 870d1da0230..23488a033f2 100644
--- a/Sources/Services/AWSMacie2/Sources/AWSMacie2/Endpoints.swift
+++ b/Sources/Services/AWSMacie2/Sources/AWSMacie2/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMacie2/Tests/AWSMacie2Tests/EndpointResolverTest.swift b/Sources/Services/AWSMacie2/Tests/AWSMacie2Tests/EndpointResolverTest.swift
index 2b53c6dfede..e6e2abaf0eb 100644
--- a/Sources/Services/AWSMacie2/Tests/AWSMacie2Tests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMacie2/Tests/AWSMacie2Tests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMacie2
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -750,7 +751,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -789,7 +790,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -828,7 +829,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -867,7 +868,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMailManager/Sources/AWSMailManager/Endpoints.swift b/Sources/Services/AWSMailManager/Sources/AWSMailManager/Endpoints.swift
index 2d802b4ad68..b690d99eb79 100644
--- a/Sources/Services/AWSMailManager/Sources/AWSMailManager/Endpoints.swift
+++ b/Sources/Services/AWSMailManager/Sources/AWSMailManager/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMailManager/Tests/AWSMailManagerTests/EndpointResolverTest.swift b/Sources/Services/AWSMailManager/Tests/AWSMailManagerTests/EndpointResolverTest.swift
index de8383e203b..164dbb3b21e 100644
--- a/Sources/Services/AWSMailManager/Tests/AWSMailManagerTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMailManager/Tests/AWSMailManagerTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMailManager
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSManagedBlockchain/Sources/AWSManagedBlockchain/Endpoints.swift b/Sources/Services/AWSManagedBlockchain/Sources/AWSManagedBlockchain/Endpoints.swift
index bf498a4cfe0..352ce3cdc98 100644
--- a/Sources/Services/AWSManagedBlockchain/Sources/AWSManagedBlockchain/Endpoints.swift
+++ b/Sources/Services/AWSManagedBlockchain/Sources/AWSManagedBlockchain/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSManagedBlockchain/Tests/AWSManagedBlockchainTests/EndpointResolverTest.swift b/Sources/Services/AWSManagedBlockchain/Tests/AWSManagedBlockchainTests/EndpointResolverTest.swift
index fc20dc80349..4567f84168f 100644
--- a/Sources/Services/AWSManagedBlockchain/Tests/AWSManagedBlockchainTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSManagedBlockchain/Tests/AWSManagedBlockchainTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSManagedBlockchain
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -390,7 +391,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -429,7 +430,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -507,7 +508,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -528,7 +529,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSManagedBlockchainQuery/Sources/AWSManagedBlockchainQuery/Endpoints.swift b/Sources/Services/AWSManagedBlockchainQuery/Sources/AWSManagedBlockchainQuery/Endpoints.swift
index 852b09817c5..8fd7f5e412b 100644
--- a/Sources/Services/AWSManagedBlockchainQuery/Sources/AWSManagedBlockchainQuery/Endpoints.swift
+++ b/Sources/Services/AWSManagedBlockchainQuery/Sources/AWSManagedBlockchainQuery/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSManagedBlockchainQuery/Tests/AWSManagedBlockchainQueryTests/EndpointResolverTest.swift b/Sources/Services/AWSManagedBlockchainQuery/Tests/AWSManagedBlockchainQueryTests/EndpointResolverTest.swift
index 5ff83100e04..2bd4c975ed0 100644
--- a/Sources/Services/AWSManagedBlockchainQuery/Tests/AWSManagedBlockchainQueryTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSManagedBlockchainQuery/Tests/AWSManagedBlockchainQueryTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSManagedBlockchainQuery
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMarketplaceAgreement/Sources/AWSMarketplaceAgreement/Endpoints.swift b/Sources/Services/AWSMarketplaceAgreement/Sources/AWSMarketplaceAgreement/Endpoints.swift
index 100ae4d33b7..59fc65894cd 100644
--- a/Sources/Services/AWSMarketplaceAgreement/Sources/AWSMarketplaceAgreement/Endpoints.swift
+++ b/Sources/Services/AWSMarketplaceAgreement/Sources/AWSMarketplaceAgreement/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMarketplaceAgreement/Tests/AWSMarketplaceAgreementTests/EndpointResolverTest.swift b/Sources/Services/AWSMarketplaceAgreement/Tests/AWSMarketplaceAgreementTests/EndpointResolverTest.swift
index ba54b3e6039..8e48bf104d7 100644
--- a/Sources/Services/AWSMarketplaceAgreement/Tests/AWSMarketplaceAgreementTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMarketplaceAgreement/Tests/AWSMarketplaceAgreementTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMarketplaceAgreement
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMarketplaceCatalog/Sources/AWSMarketplaceCatalog/Endpoints.swift b/Sources/Services/AWSMarketplaceCatalog/Sources/AWSMarketplaceCatalog/Endpoints.swift
index 6c6d753055d..a7d109b8859 100644
--- a/Sources/Services/AWSMarketplaceCatalog/Sources/AWSMarketplaceCatalog/Endpoints.swift
+++ b/Sources/Services/AWSMarketplaceCatalog/Sources/AWSMarketplaceCatalog/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMarketplaceCatalog/Tests/AWSMarketplaceCatalogTests/EndpointResolverTest.swift b/Sources/Services/AWSMarketplaceCatalog/Tests/AWSMarketplaceCatalogTests/EndpointResolverTest.swift
index 48b6f3cc58e..fbc83122473 100644
--- a/Sources/Services/AWSMarketplaceCatalog/Tests/AWSMarketplaceCatalogTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMarketplaceCatalog/Tests/AWSMarketplaceCatalogTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMarketplaceCatalog
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMarketplaceCommerceAnalytics/Sources/AWSMarketplaceCommerceAnalytics/Endpoints.swift b/Sources/Services/AWSMarketplaceCommerceAnalytics/Sources/AWSMarketplaceCommerceAnalytics/Endpoints.swift
index 8d8d353b4bf..b31944ac600 100644
--- a/Sources/Services/AWSMarketplaceCommerceAnalytics/Sources/AWSMarketplaceCommerceAnalytics/Endpoints.swift
+++ b/Sources/Services/AWSMarketplaceCommerceAnalytics/Sources/AWSMarketplaceCommerceAnalytics/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMarketplaceCommerceAnalytics/Tests/AWSMarketplaceCommerceAnalyticsTests/EndpointResolverTest.swift b/Sources/Services/AWSMarketplaceCommerceAnalytics/Tests/AWSMarketplaceCommerceAnalyticsTests/EndpointResolverTest.swift
index 00caa3d322c..56f68946eef 100644
--- a/Sources/Services/AWSMarketplaceCommerceAnalytics/Tests/AWSMarketplaceCommerceAnalyticsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMarketplaceCommerceAnalytics/Tests/AWSMarketplaceCommerceAnalyticsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMarketplaceCommerceAnalytics
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMarketplaceDeployment/Sources/AWSMarketplaceDeployment/Endpoints.swift b/Sources/Services/AWSMarketplaceDeployment/Sources/AWSMarketplaceDeployment/Endpoints.swift
index e202d9beb09..be4e526862b 100644
--- a/Sources/Services/AWSMarketplaceDeployment/Sources/AWSMarketplaceDeployment/Endpoints.swift
+++ b/Sources/Services/AWSMarketplaceDeployment/Sources/AWSMarketplaceDeployment/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMarketplaceDeployment/Tests/AWSMarketplaceDeploymentTests/EndpointResolverTest.swift b/Sources/Services/AWSMarketplaceDeployment/Tests/AWSMarketplaceDeploymentTests/EndpointResolverTest.swift
index 9dbb88db681..69968d484cd 100644
--- a/Sources/Services/AWSMarketplaceDeployment/Tests/AWSMarketplaceDeploymentTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMarketplaceDeployment/Tests/AWSMarketplaceDeploymentTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMarketplaceDeployment
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMarketplaceEntitlementService/Sources/AWSMarketplaceEntitlementService/Endpoints.swift b/Sources/Services/AWSMarketplaceEntitlementService/Sources/AWSMarketplaceEntitlementService/Endpoints.swift
index 43206bf6c43..808222d9baf 100644
--- a/Sources/Services/AWSMarketplaceEntitlementService/Sources/AWSMarketplaceEntitlementService/Endpoints.swift
+++ b/Sources/Services/AWSMarketplaceEntitlementService/Sources/AWSMarketplaceEntitlementService/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMarketplaceEntitlementService/Tests/AWSMarketplaceEntitlementServiceTests/EndpointResolverTest.swift b/Sources/Services/AWSMarketplaceEntitlementService/Tests/AWSMarketplaceEntitlementServiceTests/EndpointResolverTest.swift
index a835c450c8c..9cdc1163292 100644
--- a/Sources/Services/AWSMarketplaceEntitlementService/Tests/AWSMarketplaceEntitlementServiceTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMarketplaceEntitlementService/Tests/AWSMarketplaceEntitlementServiceTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMarketplaceEntitlementService
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,7 +88,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -107,7 +108,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -127,7 +128,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -147,7 +148,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -167,7 +168,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -187,7 +188,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -207,7 +208,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -227,7 +228,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -247,7 +248,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -267,7 +268,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -287,7 +288,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -307,7 +308,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -346,7 +347,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -385,7 +386,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -424,7 +425,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -463,7 +464,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -502,7 +503,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -541,7 +542,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -580,7 +581,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -619,7 +620,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMarketplaceMetering/Sources/AWSMarketplaceMetering/Endpoints.swift b/Sources/Services/AWSMarketplaceMetering/Sources/AWSMarketplaceMetering/Endpoints.swift
index f5e48132faf..4fc5c9a5d2c 100644
--- a/Sources/Services/AWSMarketplaceMetering/Sources/AWSMarketplaceMetering/Endpoints.swift
+++ b/Sources/Services/AWSMarketplaceMetering/Sources/AWSMarketplaceMetering/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMarketplaceMetering/Tests/AWSMarketplaceMeteringTests/EndpointResolverTest.swift b/Sources/Services/AWSMarketplaceMetering/Tests/AWSMarketplaceMeteringTests/EndpointResolverTest.swift
index e6d9c320032..821f27e36a7 100644
--- a/Sources/Services/AWSMarketplaceMetering/Tests/AWSMarketplaceMeteringTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMarketplaceMetering/Tests/AWSMarketplaceMeteringTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMarketplaceMetering
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,7 +88,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -107,7 +108,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -127,7 +128,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -147,7 +148,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -167,7 +168,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -187,7 +188,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -207,7 +208,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -227,7 +228,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -247,7 +248,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -267,7 +268,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -287,7 +288,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -307,7 +308,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -346,7 +347,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -385,7 +386,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -424,7 +425,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -463,7 +464,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -502,7 +503,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -541,7 +542,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -580,7 +581,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -619,7 +620,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMarketplaceReporting/Sources/AWSMarketplaceReporting/Endpoints.swift b/Sources/Services/AWSMarketplaceReporting/Sources/AWSMarketplaceReporting/Endpoints.swift
index 36361870876..ec2522aa642 100644
--- a/Sources/Services/AWSMarketplaceReporting/Sources/AWSMarketplaceReporting/Endpoints.swift
+++ b/Sources/Services/AWSMarketplaceReporting/Sources/AWSMarketplaceReporting/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMarketplaceReporting/Tests/AWSMarketplaceReportingTests/EndpointResolverTest.swift b/Sources/Services/AWSMarketplaceReporting/Tests/AWSMarketplaceReportingTests/EndpointResolverTest.swift
index f067c2644f3..dc753acbe57 100644
--- a/Sources/Services/AWSMarketplaceReporting/Tests/AWSMarketplaceReportingTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMarketplaceReporting/Tests/AWSMarketplaceReportingTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMarketplaceReporting
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMediaConnect/Sources/AWSMediaConnect/Endpoints.swift b/Sources/Services/AWSMediaConnect/Sources/AWSMediaConnect/Endpoints.swift
index 2772761dc9c..da73b1f6630 100644
--- a/Sources/Services/AWSMediaConnect/Sources/AWSMediaConnect/Endpoints.swift
+++ b/Sources/Services/AWSMediaConnect/Sources/AWSMediaConnect/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMediaConnect/Tests/AWSMediaConnectTests/EndpointResolverTest.swift b/Sources/Services/AWSMediaConnect/Tests/AWSMediaConnectTests/EndpointResolverTest.swift
index 1d6e5c04643..c252a05d324 100644
--- a/Sources/Services/AWSMediaConnect/Tests/AWSMediaConnectTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMediaConnect/Tests/AWSMediaConnectTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMediaConnect
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -590,7 +591,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -629,7 +630,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -707,7 +708,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMediaConvert/Sources/AWSMediaConvert/Endpoints.swift b/Sources/Services/AWSMediaConvert/Sources/AWSMediaConvert/Endpoints.swift
index 9a14c4dfd4a..b0f867b569e 100644
--- a/Sources/Services/AWSMediaConvert/Sources/AWSMediaConvert/Endpoints.swift
+++ b/Sources/Services/AWSMediaConvert/Sources/AWSMediaConvert/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMediaConvert/Tests/AWSMediaConvertTests/EndpointResolverTest.swift b/Sources/Services/AWSMediaConvert/Tests/AWSMediaConvertTests/EndpointResolverTest.swift
index c8d79cf8f4a..f0ae0156859 100644
--- a/Sources/Services/AWSMediaConvert/Tests/AWSMediaConvertTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMediaConvert/Tests/AWSMediaConvertTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMediaConvert
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -730,7 +731,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -769,7 +770,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -808,7 +809,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -847,7 +848,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -868,7 +869,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMediaLive/Sources/AWSMediaLive/Endpoints.swift b/Sources/Services/AWSMediaLive/Sources/AWSMediaLive/Endpoints.swift
index a959bd01d76..c3f6128c662 100644
--- a/Sources/Services/AWSMediaLive/Sources/AWSMediaLive/Endpoints.swift
+++ b/Sources/Services/AWSMediaLive/Sources/AWSMediaLive/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMediaLive/Tests/AWSMediaLiveTests/EndpointResolverTest.swift b/Sources/Services/AWSMediaLive/Tests/AWSMediaLiveTests/EndpointResolverTest.swift
index e0719af5a6c..2bcd3b34104 100644
--- a/Sources/Services/AWSMediaLive/Tests/AWSMediaLiveTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMediaLive/Tests/AWSMediaLiveTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMediaLive
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -610,7 +611,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -707,7 +708,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMediaPackage/Sources/AWSMediaPackage/Endpoints.swift b/Sources/Services/AWSMediaPackage/Sources/AWSMediaPackage/Endpoints.swift
index 471380788eb..5a1ee167497 100644
--- a/Sources/Services/AWSMediaPackage/Sources/AWSMediaPackage/Endpoints.swift
+++ b/Sources/Services/AWSMediaPackage/Sources/AWSMediaPackage/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMediaPackage/Tests/AWSMediaPackageTests/EndpointResolverTest.swift b/Sources/Services/AWSMediaPackage/Tests/AWSMediaPackageTests/EndpointResolverTest.swift
index 6ccea2b0c05..969c7edec95 100644
--- a/Sources/Services/AWSMediaPackage/Tests/AWSMediaPackageTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMediaPackage/Tests/AWSMediaPackageTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMediaPackage
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -590,7 +591,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -687,7 +688,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -708,7 +709,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMediaPackageV2/Sources/AWSMediaPackageV2/Endpoints.swift b/Sources/Services/AWSMediaPackageV2/Sources/AWSMediaPackageV2/Endpoints.swift
index 40189467d4b..106a67fe887 100644
--- a/Sources/Services/AWSMediaPackageV2/Sources/AWSMediaPackageV2/Endpoints.swift
+++ b/Sources/Services/AWSMediaPackageV2/Sources/AWSMediaPackageV2/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMediaPackageV2/Tests/AWSMediaPackageV2Tests/EndpointResolverTest.swift b/Sources/Services/AWSMediaPackageV2/Tests/AWSMediaPackageV2Tests/EndpointResolverTest.swift
index a131fb79abf..4991106c269 100644
--- a/Sources/Services/AWSMediaPackageV2/Tests/AWSMediaPackageV2Tests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMediaPackageV2/Tests/AWSMediaPackageV2Tests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMediaPackageV2
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMediaPackageVod/Sources/AWSMediaPackageVod/Endpoints.swift b/Sources/Services/AWSMediaPackageVod/Sources/AWSMediaPackageVod/Endpoints.swift
index e7f692e793a..82efb321000 100644
--- a/Sources/Services/AWSMediaPackageVod/Sources/AWSMediaPackageVod/Endpoints.swift
+++ b/Sources/Services/AWSMediaPackageVod/Sources/AWSMediaPackageVod/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMediaPackageVod/Tests/AWSMediaPackageVodTests/EndpointResolverTest.swift b/Sources/Services/AWSMediaPackageVod/Tests/AWSMediaPackageVodTests/EndpointResolverTest.swift
index 9e5e00a1a20..a28fc910cfc 100644
--- a/Sources/Services/AWSMediaPackageVod/Tests/AWSMediaPackageVodTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMediaPackageVod/Tests/AWSMediaPackageVodTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMediaPackageVod
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -570,7 +571,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -609,7 +610,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -687,7 +688,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -708,7 +709,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMediaStore/Sources/AWSMediaStore/Endpoints.swift b/Sources/Services/AWSMediaStore/Sources/AWSMediaStore/Endpoints.swift
index f201c4532e8..8b991373e2d 100644
--- a/Sources/Services/AWSMediaStore/Sources/AWSMediaStore/Endpoints.swift
+++ b/Sources/Services/AWSMediaStore/Sources/AWSMediaStore/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMediaStore/Tests/AWSMediaStoreTests/EndpointResolverTest.swift b/Sources/Services/AWSMediaStore/Tests/AWSMediaStoreTests/EndpointResolverTest.swift
index ef8311e4acb..e67f4297705 100644
--- a/Sources/Services/AWSMediaStore/Tests/AWSMediaStoreTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMediaStore/Tests/AWSMediaStoreTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMediaStore
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -450,7 +451,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -489,7 +490,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -528,7 +529,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -567,7 +568,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -588,7 +589,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -608,7 +609,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMediaStoreData/Sources/AWSMediaStoreData/Endpoints.swift b/Sources/Services/AWSMediaStoreData/Sources/AWSMediaStoreData/Endpoints.swift
index a1a6d54e2a7..e250e082bd9 100644
--- a/Sources/Services/AWSMediaStoreData/Sources/AWSMediaStoreData/Endpoints.swift
+++ b/Sources/Services/AWSMediaStoreData/Sources/AWSMediaStoreData/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMediaStoreData/Tests/AWSMediaStoreDataTests/EndpointResolverTest.swift b/Sources/Services/AWSMediaStoreData/Tests/AWSMediaStoreDataTests/EndpointResolverTest.swift
index 0d4644ddcb7..0c256b22eb7 100644
--- a/Sources/Services/AWSMediaStoreData/Tests/AWSMediaStoreDataTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMediaStoreData/Tests/AWSMediaStoreDataTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMediaStoreData
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -450,7 +451,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -489,7 +490,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -528,7 +529,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -567,7 +568,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -588,7 +589,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -608,7 +609,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMediaTailor/Sources/AWSMediaTailor/Endpoints.swift b/Sources/Services/AWSMediaTailor/Sources/AWSMediaTailor/Endpoints.swift
index e3a10a98cf9..3851eff596e 100644
--- a/Sources/Services/AWSMediaTailor/Sources/AWSMediaTailor/Endpoints.swift
+++ b/Sources/Services/AWSMediaTailor/Sources/AWSMediaTailor/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMediaTailor/Tests/AWSMediaTailorTests/EndpointResolverTest.swift b/Sources/Services/AWSMediaTailor/Tests/AWSMediaTailorTests/EndpointResolverTest.swift
index a0bcdc6f7dd..7b91033a163 100644
--- a/Sources/Services/AWSMediaTailor/Tests/AWSMediaTailorTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMediaTailor/Tests/AWSMediaTailorTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMediaTailor
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -410,7 +411,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -449,7 +450,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -527,7 +528,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMedicalImaging/Sources/AWSMedicalImaging/Endpoints.swift b/Sources/Services/AWSMedicalImaging/Sources/AWSMedicalImaging/Endpoints.swift
index 848fbe880e6..0e20084f0f7 100644
--- a/Sources/Services/AWSMedicalImaging/Sources/AWSMedicalImaging/Endpoints.swift
+++ b/Sources/Services/AWSMedicalImaging/Sources/AWSMedicalImaging/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMedicalImaging/Tests/AWSMedicalImagingTests/EndpointResolverTest.swift b/Sources/Services/AWSMedicalImaging/Tests/AWSMedicalImagingTests/EndpointResolverTest.swift
index 6190dc6614c..6f5cf4cf4db 100644
--- a/Sources/Services/AWSMedicalImaging/Tests/AWSMedicalImagingTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMedicalImaging/Tests/AWSMedicalImagingTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMedicalImaging
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMemoryDB/Sources/AWSMemoryDB/Endpoints.swift b/Sources/Services/AWSMemoryDB/Sources/AWSMemoryDB/Endpoints.swift
index 40075fa94df..a67d8f96127 100644
--- a/Sources/Services/AWSMemoryDB/Sources/AWSMemoryDB/Endpoints.swift
+++ b/Sources/Services/AWSMemoryDB/Sources/AWSMemoryDB/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMemoryDB/Tests/AWSMemoryDBTests/EndpointResolverTest.swift b/Sources/Services/AWSMemoryDB/Tests/AWSMemoryDBTests/EndpointResolverTest.swift
index 05d7222798a..1d5c4ebab7f 100644
--- a/Sources/Services/AWSMemoryDB/Tests/AWSMemoryDBTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMemoryDB/Tests/AWSMemoryDBTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMemoryDB
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,15 +252,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "memorydb",
                         "signingRegion": "us-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -279,7 +280,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -299,7 +300,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -319,7 +320,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -339,7 +340,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -359,7 +360,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -379,7 +380,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -399,7 +400,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -419,7 +420,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -439,7 +440,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -459,7 +460,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -479,7 +480,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -499,7 +500,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -519,7 +520,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -539,7 +540,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -559,7 +560,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -579,7 +580,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -599,7 +600,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -638,7 +639,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -677,7 +678,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -716,7 +717,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -755,7 +756,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -776,7 +777,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -796,7 +797,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMgn/Sources/AWSMgn/Endpoints.swift b/Sources/Services/AWSMgn/Sources/AWSMgn/Endpoints.swift
index 47f21558122..c135f7c3520 100644
--- a/Sources/Services/AWSMgn/Sources/AWSMgn/Endpoints.swift
+++ b/Sources/Services/AWSMgn/Sources/AWSMgn/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMgn/Tests/AWSMgnTests/EndpointResolverTest.swift b/Sources/Services/AWSMgn/Tests/AWSMgnTests/EndpointResolverTest.swift
index 674df3d6a17..334c2d8c871 100644
--- a/Sources/Services/AWSMgn/Tests/AWSMgnTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMgn/Tests/AWSMgnTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMgn
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -690,7 +691,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -729,7 +730,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -768,7 +769,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -807,7 +808,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -828,7 +829,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMigrationHub/Sources/AWSMigrationHub/Endpoints.swift b/Sources/Services/AWSMigrationHub/Sources/AWSMigrationHub/Endpoints.swift
index 24b372fb7de..4f1d74ca81c 100644
--- a/Sources/Services/AWSMigrationHub/Sources/AWSMigrationHub/Endpoints.swift
+++ b/Sources/Services/AWSMigrationHub/Sources/AWSMigrationHub/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMigrationHub/Tests/AWSMigrationHubTests/EndpointResolverTest.swift b/Sources/Services/AWSMigrationHub/Tests/AWSMigrationHubTests/EndpointResolverTest.swift
index 33ea704134b..5dba0de243d 100644
--- a/Sources/Services/AWSMigrationHub/Tests/AWSMigrationHubTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMigrationHub/Tests/AWSMigrationHubTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMigrationHub
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -410,7 +411,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -449,7 +450,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -527,7 +528,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMigrationHubConfig/Sources/AWSMigrationHubConfig/Endpoints.swift b/Sources/Services/AWSMigrationHubConfig/Sources/AWSMigrationHubConfig/Endpoints.swift
index 99b1c38af79..a45caca4afe 100644
--- a/Sources/Services/AWSMigrationHubConfig/Sources/AWSMigrationHubConfig/Endpoints.swift
+++ b/Sources/Services/AWSMigrationHubConfig/Sources/AWSMigrationHubConfig/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMigrationHubConfig/Tests/AWSMigrationHubConfigTests/EndpointResolverTest.swift b/Sources/Services/AWSMigrationHubConfig/Tests/AWSMigrationHubConfigTests/EndpointResolverTest.swift
index e7e1c08735b..7d193eef7c7 100644
--- a/Sources/Services/AWSMigrationHubConfig/Tests/AWSMigrationHubConfigTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMigrationHubConfig/Tests/AWSMigrationHubConfigTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMigrationHubConfig
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMigrationHubOrchestrator/Sources/AWSMigrationHubOrchestrator/Endpoints.swift b/Sources/Services/AWSMigrationHubOrchestrator/Sources/AWSMigrationHubOrchestrator/Endpoints.swift
index eb95b4d6c02..ec285ae6b3d 100644
--- a/Sources/Services/AWSMigrationHubOrchestrator/Sources/AWSMigrationHubOrchestrator/Endpoints.swift
+++ b/Sources/Services/AWSMigrationHubOrchestrator/Sources/AWSMigrationHubOrchestrator/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMigrationHubOrchestrator/Tests/AWSMigrationHubOrchestratorTests/EndpointResolverTest.swift b/Sources/Services/AWSMigrationHubOrchestrator/Tests/AWSMigrationHubOrchestratorTests/EndpointResolverTest.swift
index 17d4682f106..01fa139b149 100644
--- a/Sources/Services/AWSMigrationHubOrchestrator/Tests/AWSMigrationHubOrchestratorTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMigrationHubOrchestrator/Tests/AWSMigrationHubOrchestratorTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMigrationHubOrchestrator
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMigrationHubRefactorSpaces/Sources/AWSMigrationHubRefactorSpaces/Endpoints.swift b/Sources/Services/AWSMigrationHubRefactorSpaces/Sources/AWSMigrationHubRefactorSpaces/Endpoints.swift
index 717ed06c0fc..93ff9c35d52 100644
--- a/Sources/Services/AWSMigrationHubRefactorSpaces/Sources/AWSMigrationHubRefactorSpaces/Endpoints.swift
+++ b/Sources/Services/AWSMigrationHubRefactorSpaces/Sources/AWSMigrationHubRefactorSpaces/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMigrationHubRefactorSpaces/Tests/AWSMigrationHubRefactorSpacesTests/EndpointResolverTest.swift b/Sources/Services/AWSMigrationHubRefactorSpaces/Tests/AWSMigrationHubRefactorSpacesTests/EndpointResolverTest.swift
index 5481c00430a..bf33ec1d7f7 100644
--- a/Sources/Services/AWSMigrationHubRefactorSpaces/Tests/AWSMigrationHubRefactorSpacesTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMigrationHubRefactorSpaces/Tests/AWSMigrationHubRefactorSpacesTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMigrationHubRefactorSpaces
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMigrationHubStrategy/Sources/AWSMigrationHubStrategy/Endpoints.swift b/Sources/Services/AWSMigrationHubStrategy/Sources/AWSMigrationHubStrategy/Endpoints.swift
index 8bbe0c5dea1..6a0a460a05d 100644
--- a/Sources/Services/AWSMigrationHubStrategy/Sources/AWSMigrationHubStrategy/Endpoints.swift
+++ b/Sources/Services/AWSMigrationHubStrategy/Sources/AWSMigrationHubStrategy/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMigrationHubStrategy/Tests/AWSMigrationHubStrategyTests/EndpointResolverTest.swift b/Sources/Services/AWSMigrationHubStrategy/Tests/AWSMigrationHubStrategyTests/EndpointResolverTest.swift
index aa7bf180796..388d1b8ef07 100644
--- a/Sources/Services/AWSMigrationHubStrategy/Tests/AWSMigrationHubStrategyTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMigrationHubStrategy/Tests/AWSMigrationHubStrategyTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMigrationHubStrategy
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -410,7 +411,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -449,7 +450,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -527,7 +528,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSMq/Sources/AWSMq/Endpoints.swift b/Sources/Services/AWSMq/Sources/AWSMq/Endpoints.swift
index 5938dac565d..969a2d9bca3 100644
--- a/Sources/Services/AWSMq/Sources/AWSMq/Endpoints.swift
+++ b/Sources/Services/AWSMq/Sources/AWSMq/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSMq/Tests/AWSMqTests/EndpointResolverTest.swift b/Sources/Services/AWSMq/Tests/AWSMqTests/EndpointResolverTest.swift
index c8288fc46c8..011f731db0c 100644
--- a/Sources/Services/AWSMq/Tests/AWSMqTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSMq/Tests/AWSMqTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSMq
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -830,7 +831,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -869,7 +870,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -947,7 +948,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSNeptune/Sources/AWSNeptune/Endpoints.swift b/Sources/Services/AWSNeptune/Sources/AWSNeptune/Endpoints.swift
index ca1de3db84c..edad7667086 100644
--- a/Sources/Services/AWSNeptune/Sources/AWSNeptune/Endpoints.swift
+++ b/Sources/Services/AWSNeptune/Sources/AWSNeptune/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSNeptune/Tests/AWSNeptuneTests/EndpointResolverTest.swift b/Sources/Services/AWSNeptune/Tests/AWSNeptuneTests/EndpointResolverTest.swift
index 0b23eabcba4..01e69b341bb 100644
--- a/Sources/Services/AWSNeptune/Tests/AWSNeptuneTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSNeptune/Tests/AWSNeptuneTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSNeptune
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -851,7 +852,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -890,7 +891,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -929,7 +930,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1028,7 +1029,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSNeptuneGraph/Sources/AWSNeptuneGraph/Endpoints.swift b/Sources/Services/AWSNeptuneGraph/Sources/AWSNeptuneGraph/Endpoints.swift
index e9f911f335a..1c0681dc824 100644
--- a/Sources/Services/AWSNeptuneGraph/Sources/AWSNeptuneGraph/Endpoints.swift
+++ b/Sources/Services/AWSNeptuneGraph/Sources/AWSNeptuneGraph/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Parameter to determine whether current API is a control plane or dataplane API
     public let apiType: Swift.String
     /// Override the endpoint used to send this request
diff --git a/Sources/Services/AWSNeptuneGraph/Tests/AWSNeptuneGraphTests/EndpointResolverTest.swift b/Sources/Services/AWSNeptuneGraph/Tests/AWSNeptuneGraphTests/EndpointResolverTest.swift
index 8ebdaba3d02..491c4308f32 100644
--- a/Sources/Services/AWSNeptuneGraph/Tests/AWSNeptuneGraphTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSNeptuneGraph/Tests/AWSNeptuneGraphTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSNeptuneGraph
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -90,7 +91,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -152,7 +153,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -193,7 +194,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -214,7 +215,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -235,7 +236,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -256,7 +257,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -277,7 +278,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -318,7 +319,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -359,7 +360,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -380,7 +381,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -401,7 +402,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -422,7 +423,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -443,7 +444,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -484,7 +485,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -525,7 +526,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -546,7 +547,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -567,7 +568,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -588,7 +589,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -609,7 +610,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -650,7 +651,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -712,7 +713,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -733,7 +734,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -754,7 +755,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -775,7 +776,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -816,7 +817,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -857,7 +858,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -878,7 +879,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -899,7 +900,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -920,7 +921,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -941,7 +942,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -982,7 +983,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1023,7 +1024,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1044,7 +1045,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1065,7 +1066,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1086,7 +1087,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1107,7 +1108,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1148,7 +1149,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1189,7 +1190,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1210,7 +1211,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1231,7 +1232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1252,7 +1253,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1273,7 +1274,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1314,7 +1315,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1355,7 +1356,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1376,7 +1377,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1397,7 +1398,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1418,7 +1419,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSNeptunedata/Sources/AWSNeptunedata/Endpoints.swift b/Sources/Services/AWSNeptunedata/Sources/AWSNeptunedata/Endpoints.swift
index 18cbb7579ea..b4a13e857fc 100644
--- a/Sources/Services/AWSNeptunedata/Sources/AWSNeptunedata/Endpoints.swift
+++ b/Sources/Services/AWSNeptunedata/Sources/AWSNeptunedata/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSNeptunedata/Tests/AWSNeptunedataTests/EndpointResolverTest.swift b/Sources/Services/AWSNeptunedata/Tests/AWSNeptunedataTests/EndpointResolverTest.swift
index 9135ccc2bdc..ed4e77d9a63 100644
--- a/Sources/Services/AWSNeptunedata/Tests/AWSNeptunedataTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSNeptunedata/Tests/AWSNeptunedataTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSNeptunedata
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSNetworkFirewall/Sources/AWSNetworkFirewall/Endpoints.swift b/Sources/Services/AWSNetworkFirewall/Sources/AWSNetworkFirewall/Endpoints.swift
index 216a797aa5d..9de16f1d3a9 100644
--- a/Sources/Services/AWSNetworkFirewall/Sources/AWSNetworkFirewall/Endpoints.swift
+++ b/Sources/Services/AWSNetworkFirewall/Sources/AWSNetworkFirewall/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSNetworkFirewall/Tests/AWSNetworkFirewallTests/EndpointResolverTest.swift b/Sources/Services/AWSNetworkFirewall/Tests/AWSNetworkFirewallTests/EndpointResolverTest.swift
index 29fa60dbf0e..79e3f45db79 100644
--- a/Sources/Services/AWSNetworkFirewall/Tests/AWSNetworkFirewallTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSNetworkFirewall/Tests/AWSNetworkFirewallTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSNetworkFirewall
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -810,7 +811,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -849,7 +850,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -927,7 +928,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSNetworkFlowMonitor/Sources/AWSNetworkFlowMonitor/Endpoints.swift b/Sources/Services/AWSNetworkFlowMonitor/Sources/AWSNetworkFlowMonitor/Endpoints.swift
index b564cc46f0c..b00b47b94b3 100644
--- a/Sources/Services/AWSNetworkFlowMonitor/Sources/AWSNetworkFlowMonitor/Endpoints.swift
+++ b/Sources/Services/AWSNetworkFlowMonitor/Sources/AWSNetworkFlowMonitor/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSNetworkFlowMonitor/Tests/AWSNetworkFlowMonitorTests/EndpointResolverTest.swift b/Sources/Services/AWSNetworkFlowMonitor/Tests/AWSNetworkFlowMonitorTests/EndpointResolverTest.swift
index 597a4a7c90d..42d65469bda 100644
--- a/Sources/Services/AWSNetworkFlowMonitor/Tests/AWSNetworkFlowMonitorTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSNetworkFlowMonitor/Tests/AWSNetworkFlowMonitorTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSNetworkFlowMonitor
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -67,7 +68,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -86,7 +87,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -105,7 +106,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -124,7 +125,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -143,7 +144,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -162,7 +163,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -181,7 +182,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -200,7 +201,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -219,7 +220,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -238,7 +239,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -257,7 +258,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -276,7 +277,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -295,7 +296,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -314,7 +315,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSNetworkManager/Sources/AWSNetworkManager/Endpoints.swift b/Sources/Services/AWSNetworkManager/Sources/AWSNetworkManager/Endpoints.swift
index b7691d21d56..8a4b5ad8531 100644
--- a/Sources/Services/AWSNetworkManager/Sources/AWSNetworkManager/Endpoints.swift
+++ b/Sources/Services/AWSNetworkManager/Sources/AWSNetworkManager/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSNetworkManager/Tests/AWSNetworkManagerTests/EndpointResolverTest.swift b/Sources/Services/AWSNetworkManager/Tests/AWSNetworkManagerTests/EndpointResolverTest.swift
index cc0fd713eb3..d36ea981ddc 100644
--- a/Sources/Services/AWSNetworkManager/Tests/AWSNetworkManagerTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSNetworkManager/Tests/AWSNetworkManagerTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSNetworkManager
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,14 +88,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-west-2"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -114,14 +115,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-west-2"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -141,14 +142,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-west-2"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -168,14 +169,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-west-2"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -195,14 +196,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -222,14 +223,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -249,14 +250,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -276,14 +277,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -303,14 +304,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -330,14 +331,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -357,14 +358,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -384,14 +385,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -430,14 +431,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -476,14 +477,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -522,14 +523,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,14 +569,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -614,14 +615,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -660,14 +661,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -706,14 +707,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -752,14 +753,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSNetworkMonitor/Sources/AWSNetworkMonitor/Endpoints.swift b/Sources/Services/AWSNetworkMonitor/Sources/AWSNetworkMonitor/Endpoints.swift
index bbf05568d89..d6e8943cea1 100644
--- a/Sources/Services/AWSNetworkMonitor/Sources/AWSNetworkMonitor/Endpoints.swift
+++ b/Sources/Services/AWSNetworkMonitor/Sources/AWSNetworkMonitor/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSNetworkMonitor/Tests/AWSNetworkMonitorTests/EndpointResolverTest.swift b/Sources/Services/AWSNetworkMonitor/Tests/AWSNetworkMonitorTests/EndpointResolverTest.swift
index 69bea80c229..64b82080655 100644
--- a/Sources/Services/AWSNetworkMonitor/Tests/AWSNetworkMonitorTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSNetworkMonitor/Tests/AWSNetworkMonitorTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSNetworkMonitor
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSNotifications/Sources/AWSNotifications/Endpoints.swift b/Sources/Services/AWSNotifications/Sources/AWSNotifications/Endpoints.swift
index 872b4999173..c966d4aaabd 100644
--- a/Sources/Services/AWSNotifications/Sources/AWSNotifications/Endpoints.swift
+++ b/Sources/Services/AWSNotifications/Sources/AWSNotifications/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSNotifications/Tests/AWSNotificationsTests/EndpointResolverTest.swift b/Sources/Services/AWSNotifications/Tests/AWSNotificationsTests/EndpointResolverTest.swift
index c2b52fe9cf8..55ffae38340 100644
--- a/Sources/Services/AWSNotifications/Tests/AWSNotificationsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSNotifications/Tests/AWSNotificationsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSNotifications
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -67,7 +68,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -86,7 +87,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -105,7 +106,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -124,7 +125,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -143,7 +144,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -162,7 +163,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -181,7 +182,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -200,7 +201,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -219,7 +220,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -238,7 +239,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -257,7 +258,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -276,7 +277,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -295,7 +296,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -314,7 +315,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSNotificationsContacts/Sources/AWSNotificationsContacts/Endpoints.swift b/Sources/Services/AWSNotificationsContacts/Sources/AWSNotificationsContacts/Endpoints.swift
index f10c594045e..323d6161c36 100644
--- a/Sources/Services/AWSNotificationsContacts/Sources/AWSNotificationsContacts/Endpoints.swift
+++ b/Sources/Services/AWSNotificationsContacts/Sources/AWSNotificationsContacts/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSNotificationsContacts/Tests/AWSNotificationsContactsTests/EndpointResolverTest.swift b/Sources/Services/AWSNotificationsContacts/Tests/AWSNotificationsContactsTests/EndpointResolverTest.swift
index 93d816337eb..4943b9720e4 100644
--- a/Sources/Services/AWSNotificationsContacts/Tests/AWSNotificationsContactsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSNotificationsContacts/Tests/AWSNotificationsContactsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSNotificationsContacts
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -67,14 +68,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -93,14 +94,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -119,14 +120,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -145,14 +146,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,14 +172,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -197,14 +198,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -223,14 +224,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -249,14 +250,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -275,14 +276,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -301,14 +302,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -327,14 +328,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -353,14 +354,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -379,14 +380,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -405,14 +406,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSOAM/Sources/AWSOAM/Endpoints.swift b/Sources/Services/AWSOAM/Sources/AWSOAM/Endpoints.swift
index 5620d1e3f8b..fa131452940 100644
--- a/Sources/Services/AWSOAM/Sources/AWSOAM/Endpoints.swift
+++ b/Sources/Services/AWSOAM/Sources/AWSOAM/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSOAM/Tests/AWSOAMTests/EndpointResolverTest.swift b/Sources/Services/AWSOAM/Tests/AWSOAMTests/EndpointResolverTest.swift
index 20899bb3b40..e271202826f 100644
--- a/Sources/Services/AWSOAM/Tests/AWSOAMTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSOAM/Tests/AWSOAMTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSOAM
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSOSIS/Sources/AWSOSIS/Endpoints.swift b/Sources/Services/AWSOSIS/Sources/AWSOSIS/Endpoints.swift
index c6050366357..6ffcf96c075 100644
--- a/Sources/Services/AWSOSIS/Sources/AWSOSIS/Endpoints.swift
+++ b/Sources/Services/AWSOSIS/Sources/AWSOSIS/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSOSIS/Tests/AWSOSISTests/EndpointResolverTest.swift b/Sources/Services/AWSOSIS/Tests/AWSOSISTests/EndpointResolverTest.swift
index 4d8814d3b91..bf57ff488a1 100644
--- a/Sources/Services/AWSOSIS/Tests/AWSOSISTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSOSIS/Tests/AWSOSISTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSOSIS
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSObservabilityAdmin/Sources/AWSObservabilityAdmin/Endpoints.swift b/Sources/Services/AWSObservabilityAdmin/Sources/AWSObservabilityAdmin/Endpoints.swift
index 349402449a3..88b1dd66c1e 100644
--- a/Sources/Services/AWSObservabilityAdmin/Sources/AWSObservabilityAdmin/Endpoints.swift
+++ b/Sources/Services/AWSObservabilityAdmin/Sources/AWSObservabilityAdmin/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSObservabilityAdmin/Tests/AWSObservabilityAdminTests/EndpointResolverTest.swift b/Sources/Services/AWSObservabilityAdmin/Tests/AWSObservabilityAdminTests/EndpointResolverTest.swift
index 1433ac7549e..d0302ec106c 100644
--- a/Sources/Services/AWSObservabilityAdmin/Tests/AWSObservabilityAdminTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSObservabilityAdmin/Tests/AWSObservabilityAdminTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSObservabilityAdmin
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSOmics/Sources/AWSOmics/Endpoints.swift b/Sources/Services/AWSOmics/Sources/AWSOmics/Endpoints.swift
index ab5e28300ee..abd326a98a2 100644
--- a/Sources/Services/AWSOmics/Sources/AWSOmics/Endpoints.swift
+++ b/Sources/Services/AWSOmics/Sources/AWSOmics/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSOmics/Tests/AWSOmicsTests/EndpointResolverTest.swift b/Sources/Services/AWSOmics/Tests/AWSOmicsTests/EndpointResolverTest.swift
index 17d4aad7e3c..e15c29014ad 100644
--- a/Sources/Services/AWSOmics/Tests/AWSOmicsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSOmics/Tests/AWSOmicsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSOmics
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSOpenSearch/Sources/AWSOpenSearch/Endpoints.swift b/Sources/Services/AWSOpenSearch/Sources/AWSOpenSearch/Endpoints.swift
index f303dd48a00..7fd76693fb8 100644
--- a/Sources/Services/AWSOpenSearch/Sources/AWSOpenSearch/Endpoints.swift
+++ b/Sources/Services/AWSOpenSearch/Sources/AWSOpenSearch/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSOpenSearch/Tests/AWSOpenSearchTests/EndpointResolverTest.swift b/Sources/Services/AWSOpenSearch/Tests/AWSOpenSearchTests/EndpointResolverTest.swift
index 75e51c6a3be..68f101e88c5 100644
--- a/Sources/Services/AWSOpenSearch/Tests/AWSOpenSearchTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSOpenSearch/Tests/AWSOpenSearchTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSOpenSearch
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSOpenSearchServerless/Sources/AWSOpenSearchServerless/Endpoints.swift b/Sources/Services/AWSOpenSearchServerless/Sources/AWSOpenSearchServerless/Endpoints.swift
index 57546ad4c79..a114315e7f4 100644
--- a/Sources/Services/AWSOpenSearchServerless/Sources/AWSOpenSearchServerless/Endpoints.swift
+++ b/Sources/Services/AWSOpenSearchServerless/Sources/AWSOpenSearchServerless/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSOpenSearchServerless/Tests/AWSOpenSearchServerlessTests/EndpointResolverTest.swift b/Sources/Services/AWSOpenSearchServerless/Tests/AWSOpenSearchServerlessTests/EndpointResolverTest.swift
index d25b6687da2..c183e90b0a1 100644
--- a/Sources/Services/AWSOpenSearchServerless/Tests/AWSOpenSearchServerlessTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSOpenSearchServerless/Tests/AWSOpenSearchServerlessTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSOpenSearchServerless
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSOpsWorks/Sources/AWSOpsWorks/Endpoints.swift b/Sources/Services/AWSOpsWorks/Sources/AWSOpsWorks/Endpoints.swift
index 7b0f4e46c0e..42b530bdec3 100644
--- a/Sources/Services/AWSOpsWorks/Sources/AWSOpsWorks/Endpoints.swift
+++ b/Sources/Services/AWSOpsWorks/Sources/AWSOpsWorks/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSOpsWorks/Tests/AWSOpsWorksTests/EndpointResolverTest.swift b/Sources/Services/AWSOpsWorks/Tests/AWSOpsWorksTests/EndpointResolverTest.swift
index 528b460bd7e..b2cbed6a127 100644
--- a/Sources/Services/AWSOpsWorks/Tests/AWSOpsWorksTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSOpsWorks/Tests/AWSOpsWorksTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSOpsWorks
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -570,7 +571,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -609,7 +610,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -687,7 +688,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -708,7 +709,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSOpsWorksCM/Sources/AWSOpsWorksCM/Endpoints.swift b/Sources/Services/AWSOpsWorksCM/Sources/AWSOpsWorksCM/Endpoints.swift
index eff275319b3..bf0af486719 100644
--- a/Sources/Services/AWSOpsWorksCM/Sources/AWSOpsWorksCM/Endpoints.swift
+++ b/Sources/Services/AWSOpsWorksCM/Sources/AWSOpsWorksCM/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSOpsWorksCM/Tests/AWSOpsWorksCMTests/EndpointResolverTest.swift b/Sources/Services/AWSOpsWorksCM/Tests/AWSOpsWorksCMTests/EndpointResolverTest.swift
index 437e1e0280f..3695fbced0a 100644
--- a/Sources/Services/AWSOpsWorksCM/Tests/AWSOpsWorksCMTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSOpsWorksCM/Tests/AWSOpsWorksCMTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSOpsWorksCM
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -450,7 +451,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -489,7 +490,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -528,7 +529,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -567,7 +568,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -588,7 +589,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -608,7 +609,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSOrganizations/Sources/AWSOrganizations/Endpoints.swift b/Sources/Services/AWSOrganizations/Sources/AWSOrganizations/Endpoints.swift
index ff87326d5ae..01c3946ec48 100644
--- a/Sources/Services/AWSOrganizations/Sources/AWSOrganizations/Endpoints.swift
+++ b/Sources/Services/AWSOrganizations/Sources/AWSOrganizations/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSOrganizations/Tests/AWSOrganizationsTests/EndpointResolverTest.swift b/Sources/Services/AWSOrganizations/Tests/AWSOrganizationsTests/EndpointResolverTest.swift
index c0e1cffb0a1..fbb7071d53b 100644
--- a/Sources/Services/AWSOrganizations/Tests/AWSOrganizationsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSOrganizations/Tests/AWSOrganizationsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSOrganizations
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,15 +32,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "organizations",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -59,15 +60,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "organizations",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,7 +88,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -107,15 +108,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "organizations",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -135,7 +136,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -155,15 +156,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "organizations",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -183,15 +184,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "organizations",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,15 +272,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "organizations",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -299,15 +300,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "organizations",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -327,15 +328,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "organizations",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -355,7 +356,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -375,15 +376,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "organizations",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -403,7 +404,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -423,15 +424,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "organizations",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,15 +452,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "organizations",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -498,7 +499,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -537,15 +538,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "organizations",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -565,15 +566,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "organizations",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -612,7 +613,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,15 +652,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "organizations",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -679,15 +680,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "organizations",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -708,7 +709,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSOutposts/Sources/AWSOutposts/Endpoints.swift b/Sources/Services/AWSOutposts/Sources/AWSOutposts/Endpoints.swift
index c0ef09b867c..8d0645162f1 100644
--- a/Sources/Services/AWSOutposts/Sources/AWSOutposts/Endpoints.swift
+++ b/Sources/Services/AWSOutposts/Sources/AWSOutposts/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSOutposts/Tests/AWSOutpostsTests/EndpointResolverTest.swift b/Sources/Services/AWSOutposts/Tests/AWSOutpostsTests/EndpointResolverTest.swift
index 10b40a337e4..1bc6b07b9c1 100644
--- a/Sources/Services/AWSOutposts/Tests/AWSOutpostsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSOutposts/Tests/AWSOutpostsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSOutposts
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -830,7 +831,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -927,7 +928,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSPCS/Sources/AWSPCS/Endpoints.swift b/Sources/Services/AWSPCS/Sources/AWSPCS/Endpoints.swift
index d2287a82ace..8dac6761409 100644
--- a/Sources/Services/AWSPCS/Sources/AWSPCS/Endpoints.swift
+++ b/Sources/Services/AWSPCS/Sources/AWSPCS/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSPCS/Tests/AWSPCSTests/EndpointResolverTest.swift b/Sources/Services/AWSPCS/Tests/AWSPCSTests/EndpointResolverTest.swift
index 0447068150c..9eb220f4f87 100644
--- a/Sources/Services/AWSPCS/Tests/AWSPCSTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSPCS/Tests/AWSPCSTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSPCS
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSPI/Sources/AWSPI/Endpoints.swift b/Sources/Services/AWSPI/Sources/AWSPI/Endpoints.swift
index 21d368c97ab..b0413b3d812 100644
--- a/Sources/Services/AWSPI/Sources/AWSPI/Endpoints.swift
+++ b/Sources/Services/AWSPI/Sources/AWSPI/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSPI/Tests/AWSPITests/EndpointResolverTest.swift b/Sources/Services/AWSPI/Tests/AWSPITests/EndpointResolverTest.swift
index 428fde619b0..8511b13a4eb 100644
--- a/Sources/Services/AWSPI/Tests/AWSPITests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSPI/Tests/AWSPITests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSPI
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -710,7 +711,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -749,7 +750,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -788,7 +789,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -827,7 +828,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -868,7 +869,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSPanorama/Sources/AWSPanorama/Endpoints.swift b/Sources/Services/AWSPanorama/Sources/AWSPanorama/Endpoints.swift
index 9430d5d0449..758ba79902c 100644
--- a/Sources/Services/AWSPanorama/Sources/AWSPanorama/Endpoints.swift
+++ b/Sources/Services/AWSPanorama/Sources/AWSPanorama/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSPanorama/Tests/AWSPanoramaTests/EndpointResolverTest.swift b/Sources/Services/AWSPanorama/Tests/AWSPanoramaTests/EndpointResolverTest.swift
index fc660f859ec..eeda2a9e952 100644
--- a/Sources/Services/AWSPanorama/Tests/AWSPanoramaTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSPanorama/Tests/AWSPanoramaTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSPanorama
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSPartnerCentralSelling/Sources/AWSPartnerCentralSelling/Endpoints.swift b/Sources/Services/AWSPartnerCentralSelling/Sources/AWSPartnerCentralSelling/Endpoints.swift
index 117856388cb..840bba3e7a6 100644
--- a/Sources/Services/AWSPartnerCentralSelling/Sources/AWSPartnerCentralSelling/Endpoints.swift
+++ b/Sources/Services/AWSPartnerCentralSelling/Sources/AWSPartnerCentralSelling/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSPartnerCentralSelling/Tests/AWSPartnerCentralSellingTests/EndpointResolverTest.swift b/Sources/Services/AWSPartnerCentralSelling/Tests/AWSPartnerCentralSellingTests/EndpointResolverTest.swift
index a01d8271880..2d578baa1bb 100644
--- a/Sources/Services/AWSPartnerCentralSelling/Tests/AWSPartnerCentralSellingTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSPartnerCentralSelling/Tests/AWSPartnerCentralSellingTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSPartnerCentralSelling
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -67,7 +68,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -86,7 +87,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -105,7 +106,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -124,7 +125,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -143,7 +144,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -162,7 +163,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -181,7 +182,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -200,7 +201,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -219,7 +220,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -238,7 +239,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -257,7 +258,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -276,7 +277,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -295,7 +296,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -314,7 +315,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSPaymentCryptography/Sources/AWSPaymentCryptography/Endpoints.swift b/Sources/Services/AWSPaymentCryptography/Sources/AWSPaymentCryptography/Endpoints.swift
index b8f0217c252..8c6e4a8d7a3 100644
--- a/Sources/Services/AWSPaymentCryptography/Sources/AWSPaymentCryptography/Endpoints.swift
+++ b/Sources/Services/AWSPaymentCryptography/Sources/AWSPaymentCryptography/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSPaymentCryptography/Tests/AWSPaymentCryptographyTests/EndpointResolverTest.swift b/Sources/Services/AWSPaymentCryptography/Tests/AWSPaymentCryptographyTests/EndpointResolverTest.swift
index ffdcbbb6f77..220ac7114ec 100644
--- a/Sources/Services/AWSPaymentCryptography/Tests/AWSPaymentCryptographyTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSPaymentCryptography/Tests/AWSPaymentCryptographyTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSPaymentCryptography
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSPaymentCryptographyData/Sources/AWSPaymentCryptographyData/Endpoints.swift b/Sources/Services/AWSPaymentCryptographyData/Sources/AWSPaymentCryptographyData/Endpoints.swift
index 86e7dc88605..c035eb6017c 100644
--- a/Sources/Services/AWSPaymentCryptographyData/Sources/AWSPaymentCryptographyData/Endpoints.swift
+++ b/Sources/Services/AWSPaymentCryptographyData/Sources/AWSPaymentCryptographyData/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSPaymentCryptographyData/Tests/AWSPaymentCryptographyDataTests/EndpointResolverTest.swift b/Sources/Services/AWSPaymentCryptographyData/Tests/AWSPaymentCryptographyDataTests/EndpointResolverTest.swift
index 19a76d216cc..cd1f80a73a9 100644
--- a/Sources/Services/AWSPaymentCryptographyData/Tests/AWSPaymentCryptographyDataTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSPaymentCryptographyData/Tests/AWSPaymentCryptographyDataTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSPaymentCryptographyData
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSPcaConnectorAd/Sources/AWSPcaConnectorAd/Endpoints.swift b/Sources/Services/AWSPcaConnectorAd/Sources/AWSPcaConnectorAd/Endpoints.swift
index 7e898a31a55..1c767736ffb 100644
--- a/Sources/Services/AWSPcaConnectorAd/Sources/AWSPcaConnectorAd/Endpoints.swift
+++ b/Sources/Services/AWSPcaConnectorAd/Sources/AWSPcaConnectorAd/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSPcaConnectorAd/Tests/AWSPcaConnectorAdTests/EndpointResolverTest.swift b/Sources/Services/AWSPcaConnectorAd/Tests/AWSPcaConnectorAdTests/EndpointResolverTest.swift
index 0d1956cd4a0..f8a7ce12957 100644
--- a/Sources/Services/AWSPcaConnectorAd/Tests/AWSPcaConnectorAdTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSPcaConnectorAd/Tests/AWSPcaConnectorAdTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSPcaConnectorAd
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSPcaConnectorScep/Sources/AWSPcaConnectorScep/Endpoints.swift b/Sources/Services/AWSPcaConnectorScep/Sources/AWSPcaConnectorScep/Endpoints.swift
index 50ed99b9c3f..ee6e7109053 100644
--- a/Sources/Services/AWSPcaConnectorScep/Sources/AWSPcaConnectorScep/Endpoints.swift
+++ b/Sources/Services/AWSPcaConnectorScep/Sources/AWSPcaConnectorScep/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSPcaConnectorScep/Tests/AWSPcaConnectorScepTests/EndpointResolverTest.swift b/Sources/Services/AWSPcaConnectorScep/Tests/AWSPcaConnectorScepTests/EndpointResolverTest.swift
index 39251ea74b4..f82788f0558 100644
--- a/Sources/Services/AWSPcaConnectorScep/Tests/AWSPcaConnectorScepTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSPcaConnectorScep/Tests/AWSPcaConnectorScepTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSPcaConnectorScep
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSPersonalize/Sources/AWSPersonalize/Endpoints.swift b/Sources/Services/AWSPersonalize/Sources/AWSPersonalize/Endpoints.swift
index e09f35f46fa..97ffe60f29d 100644
--- a/Sources/Services/AWSPersonalize/Sources/AWSPersonalize/Endpoints.swift
+++ b/Sources/Services/AWSPersonalize/Sources/AWSPersonalize/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSPersonalize/Tests/AWSPersonalizeTests/EndpointResolverTest.swift b/Sources/Services/AWSPersonalize/Tests/AWSPersonalizeTests/EndpointResolverTest.swift
index eaf195dd2b6..922ac7c10d8 100644
--- a/Sources/Services/AWSPersonalize/Tests/AWSPersonalizeTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSPersonalize/Tests/AWSPersonalizeTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSPersonalize
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -490,7 +491,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -529,7 +530,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -607,7 +608,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSPersonalizeEvents/Sources/AWSPersonalizeEvents/Endpoints.swift b/Sources/Services/AWSPersonalizeEvents/Sources/AWSPersonalizeEvents/Endpoints.swift
index 596f0401b4f..f465e8d964f 100644
--- a/Sources/Services/AWSPersonalizeEvents/Sources/AWSPersonalizeEvents/Endpoints.swift
+++ b/Sources/Services/AWSPersonalizeEvents/Sources/AWSPersonalizeEvents/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSPersonalizeEvents/Tests/AWSPersonalizeEventsTests/EndpointResolverTest.swift b/Sources/Services/AWSPersonalizeEvents/Tests/AWSPersonalizeEventsTests/EndpointResolverTest.swift
index 9338ecd4b7f..9b0a87cfc95 100644
--- a/Sources/Services/AWSPersonalizeEvents/Tests/AWSPersonalizeEventsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSPersonalizeEvents/Tests/AWSPersonalizeEventsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSPersonalizeEvents
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSPersonalizeRuntime/Sources/AWSPersonalizeRuntime/Endpoints.swift b/Sources/Services/AWSPersonalizeRuntime/Sources/AWSPersonalizeRuntime/Endpoints.swift
index 8190d6dace1..14bb088d73f 100644
--- a/Sources/Services/AWSPersonalizeRuntime/Sources/AWSPersonalizeRuntime/Endpoints.swift
+++ b/Sources/Services/AWSPersonalizeRuntime/Sources/AWSPersonalizeRuntime/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSPersonalizeRuntime/Tests/AWSPersonalizeRuntimeTests/EndpointResolverTest.swift b/Sources/Services/AWSPersonalizeRuntime/Tests/AWSPersonalizeRuntimeTests/EndpointResolverTest.swift
index 3586e4acddb..36ecc1d7757 100644
--- a/Sources/Services/AWSPersonalizeRuntime/Tests/AWSPersonalizeRuntimeTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSPersonalizeRuntime/Tests/AWSPersonalizeRuntimeTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSPersonalizeRuntime
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSPinpoint/Sources/AWSPinpoint/Endpoints.swift b/Sources/Services/AWSPinpoint/Sources/AWSPinpoint/Endpoints.swift
index 3ae7f92e495..8a1c8b9c6f3 100644
--- a/Sources/Services/AWSPinpoint/Sources/AWSPinpoint/Endpoints.swift
+++ b/Sources/Services/AWSPinpoint/Sources/AWSPinpoint/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSPinpoint/Tests/AWSPinpointTests/EndpointResolverTest.swift b/Sources/Services/AWSPinpoint/Tests/AWSPinpointTests/EndpointResolverTest.swift
index 5d52b78f6a0..72d53d92dc7 100644
--- a/Sources/Services/AWSPinpoint/Tests/AWSPinpointTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSPinpoint/Tests/AWSPinpointTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSPinpoint
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -550,7 +551,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -589,7 +590,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -667,7 +668,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -688,7 +689,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -708,7 +709,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSPinpointEmail/Sources/AWSPinpointEmail/Endpoints.swift b/Sources/Services/AWSPinpointEmail/Sources/AWSPinpointEmail/Endpoints.swift
index f2eeefd56a9..b276839b3a6 100644
--- a/Sources/Services/AWSPinpointEmail/Sources/AWSPinpointEmail/Endpoints.swift
+++ b/Sources/Services/AWSPinpointEmail/Sources/AWSPinpointEmail/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSPinpointEmail/Tests/AWSPinpointEmailTests/EndpointResolverTest.swift b/Sources/Services/AWSPinpointEmail/Tests/AWSPinpointEmailTests/EndpointResolverTest.swift
index db6bad0f8ca..7c5f0212a22 100644
--- a/Sources/Services/AWSPinpointEmail/Tests/AWSPinpointEmailTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSPinpointEmail/Tests/AWSPinpointEmailTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSPinpointEmail
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -730,7 +731,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -769,7 +770,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -808,7 +809,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -847,7 +848,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -868,7 +869,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSPinpointSMSVoice/Sources/AWSPinpointSMSVoice/Endpoints.swift b/Sources/Services/AWSPinpointSMSVoice/Sources/AWSPinpointSMSVoice/Endpoints.swift
index 7befe89eb34..a0e43334be8 100644
--- a/Sources/Services/AWSPinpointSMSVoice/Sources/AWSPinpointSMSVoice/Endpoints.swift
+++ b/Sources/Services/AWSPinpointSMSVoice/Sources/AWSPinpointSMSVoice/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSPinpointSMSVoice/Tests/AWSPinpointSMSVoiceTests/EndpointResolverTest.swift b/Sources/Services/AWSPinpointSMSVoice/Tests/AWSPinpointSMSVoiceTests/EndpointResolverTest.swift
index 3899d4c9eca..ebadfd8583a 100644
--- a/Sources/Services/AWSPinpointSMSVoice/Tests/AWSPinpointSMSVoiceTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSPinpointSMSVoice/Tests/AWSPinpointSMSVoiceTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSPinpointSMSVoice
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSPinpointSMSVoiceV2/Sources/AWSPinpointSMSVoiceV2/Endpoints.swift b/Sources/Services/AWSPinpointSMSVoiceV2/Sources/AWSPinpointSMSVoiceV2/Endpoints.swift
index 1b82499184e..0be9c301e4b 100644
--- a/Sources/Services/AWSPinpointSMSVoiceV2/Sources/AWSPinpointSMSVoiceV2/Endpoints.swift
+++ b/Sources/Services/AWSPinpointSMSVoiceV2/Sources/AWSPinpointSMSVoiceV2/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSPinpointSMSVoiceV2/Tests/AWSPinpointSMSVoiceV2Tests/EndpointResolverTest.swift b/Sources/Services/AWSPinpointSMSVoiceV2/Tests/AWSPinpointSMSVoiceV2Tests/EndpointResolverTest.swift
index 1f5bd6e7a49..f4417105fed 100644
--- a/Sources/Services/AWSPinpointSMSVoiceV2/Tests/AWSPinpointSMSVoiceV2Tests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSPinpointSMSVoiceV2/Tests/AWSPinpointSMSVoiceV2Tests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSPinpointSMSVoiceV2
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -490,7 +491,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -529,7 +530,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -607,7 +608,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSPipes/Sources/AWSPipes/Endpoints.swift b/Sources/Services/AWSPipes/Sources/AWSPipes/Endpoints.swift
index 25c3c5d3879..285056c74ef 100644
--- a/Sources/Services/AWSPipes/Sources/AWSPipes/Endpoints.swift
+++ b/Sources/Services/AWSPipes/Sources/AWSPipes/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSPipes/Tests/AWSPipesTests/EndpointResolverTest.swift b/Sources/Services/AWSPipes/Tests/AWSPipesTests/EndpointResolverTest.swift
index 984e40138b8..2da2ce70faf 100644
--- a/Sources/Services/AWSPipes/Tests/AWSPipesTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSPipes/Tests/AWSPipesTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSPipes
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSPolly/Sources/AWSPolly/Endpoints.swift b/Sources/Services/AWSPolly/Sources/AWSPolly/Endpoints.swift
index 59c89979c0f..bc67e4c8fd7 100644
--- a/Sources/Services/AWSPolly/Sources/AWSPolly/Endpoints.swift
+++ b/Sources/Services/AWSPolly/Sources/AWSPolly/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSPolly/Tests/AWSPollyTests/EndpointResolverTest.swift b/Sources/Services/AWSPolly/Tests/AWSPollyTests/EndpointResolverTest.swift
index c2b98337b43..6e761e43cc1 100644
--- a/Sources/Services/AWSPolly/Tests/AWSPollyTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSPolly/Tests/AWSPollyTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSPolly
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -770,7 +771,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -809,7 +810,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -887,7 +888,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSPricing/Sources/AWSPricing/Endpoints.swift b/Sources/Services/AWSPricing/Sources/AWSPricing/Endpoints.swift
index f04198140de..9997f76268d 100644
--- a/Sources/Services/AWSPricing/Sources/AWSPricing/Endpoints.swift
+++ b/Sources/Services/AWSPricing/Sources/AWSPricing/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSPricing/Tests/AWSPricingTests/EndpointResolverTest.swift b/Sources/Services/AWSPricing/Tests/AWSPricingTests/EndpointResolverTest.swift
index f7fc942a9fd..240d2361ff4 100644
--- a/Sources/Services/AWSPricing/Tests/AWSPricingTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSPricing/Tests/AWSPricingTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSPricing
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -310,7 +311,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -349,7 +350,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -388,7 +389,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -427,7 +428,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSPrivateNetworks/Sources/AWSPrivateNetworks/Endpoints.swift b/Sources/Services/AWSPrivateNetworks/Sources/AWSPrivateNetworks/Endpoints.swift
index b46f3c6b65e..be8af2ebb8e 100644
--- a/Sources/Services/AWSPrivateNetworks/Sources/AWSPrivateNetworks/Endpoints.swift
+++ b/Sources/Services/AWSPrivateNetworks/Sources/AWSPrivateNetworks/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSPrivateNetworks/Tests/AWSPrivateNetworksTests/EndpointResolverTest.swift b/Sources/Services/AWSPrivateNetworks/Tests/AWSPrivateNetworksTests/EndpointResolverTest.swift
index 3a269031cab..947de10f279 100644
--- a/Sources/Services/AWSPrivateNetworks/Tests/AWSPrivateNetworksTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSPrivateNetworks/Tests/AWSPrivateNetworksTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSPrivateNetworks
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSProton/Sources/AWSProton/Endpoints.swift b/Sources/Services/AWSProton/Sources/AWSProton/Endpoints.swift
index b0ba991ed54..0b855a2084a 100644
--- a/Sources/Services/AWSProton/Sources/AWSProton/Endpoints.swift
+++ b/Sources/Services/AWSProton/Sources/AWSProton/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSProton/Tests/AWSProtonTests/EndpointResolverTest.swift b/Sources/Services/AWSProton/Tests/AWSProtonTests/EndpointResolverTest.swift
index 544edc93f73..84c7e5b3449 100644
--- a/Sources/Services/AWSProton/Tests/AWSProtonTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSProton/Tests/AWSProtonTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSProton
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -370,7 +371,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -409,7 +410,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -487,7 +488,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -508,7 +509,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -528,7 +529,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSQApps/Sources/AWSQApps/Endpoints.swift b/Sources/Services/AWSQApps/Sources/AWSQApps/Endpoints.swift
index 1d162ff0c19..05dfe425083 100644
--- a/Sources/Services/AWSQApps/Sources/AWSQApps/Endpoints.swift
+++ b/Sources/Services/AWSQApps/Sources/AWSQApps/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSQApps/Tests/AWSQAppsTests/EndpointResolverTest.swift b/Sources/Services/AWSQApps/Tests/AWSQAppsTests/EndpointResolverTest.swift
index 1327d17cda1..01e35006e8a 100644
--- a/Sources/Services/AWSQApps/Tests/AWSQAppsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSQApps/Tests/AWSQAppsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSQApps
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSQBusiness/Sources/AWSQBusiness/Endpoints.swift b/Sources/Services/AWSQBusiness/Sources/AWSQBusiness/Endpoints.swift
index b7dcbd2d4d6..a4c65dedcde 100644
--- a/Sources/Services/AWSQBusiness/Sources/AWSQBusiness/Endpoints.swift
+++ b/Sources/Services/AWSQBusiness/Sources/AWSQBusiness/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSQBusiness/Tests/AWSQBusinessTests/EndpointResolverTest.swift b/Sources/Services/AWSQBusiness/Tests/AWSQBusinessTests/EndpointResolverTest.swift
index 57a0c53e4d2..b9db233b08c 100644
--- a/Sources/Services/AWSQBusiness/Tests/AWSQBusinessTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSQBusiness/Tests/AWSQBusinessTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSQBusiness
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -49,7 +50,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -68,7 +69,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,7 +88,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -106,7 +107,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -125,7 +126,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -145,7 +146,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -164,7 +165,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSQConnect/Sources/AWSQConnect/Endpoints.swift b/Sources/Services/AWSQConnect/Sources/AWSQConnect/Endpoints.swift
index f0b5eef7168..6fd378ad1da 100644
--- a/Sources/Services/AWSQConnect/Sources/AWSQConnect/Endpoints.swift
+++ b/Sources/Services/AWSQConnect/Sources/AWSQConnect/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSQConnect/Tests/AWSQConnectTests/EndpointResolverTest.swift b/Sources/Services/AWSQConnect/Tests/AWSQConnectTests/EndpointResolverTest.swift
index c7af684ce1f..543b2f6bb1b 100644
--- a/Sources/Services/AWSQConnect/Tests/AWSQConnectTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSQConnect/Tests/AWSQConnectTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSQConnect
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSQLDB/Sources/AWSQLDB/Endpoints.swift b/Sources/Services/AWSQLDB/Sources/AWSQLDB/Endpoints.swift
index ab99ddc980c..df69db0d44f 100644
--- a/Sources/Services/AWSQLDB/Sources/AWSQLDB/Endpoints.swift
+++ b/Sources/Services/AWSQLDB/Sources/AWSQLDB/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSQLDB/Tests/AWSQLDBTests/EndpointResolverTest.swift b/Sources/Services/AWSQLDB/Tests/AWSQLDBTests/EndpointResolverTest.swift
index 77e2a8bc1f2..011bb55e655 100644
--- a/Sources/Services/AWSQLDB/Tests/AWSQLDBTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSQLDB/Tests/AWSQLDBTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSQLDB
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -550,7 +551,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -589,7 +590,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -667,7 +668,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -688,7 +689,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -708,7 +709,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSQLDBSession/Sources/AWSQLDBSession/Endpoints.swift b/Sources/Services/AWSQLDBSession/Sources/AWSQLDBSession/Endpoints.swift
index a619d93a8d1..8ccc125e757 100644
--- a/Sources/Services/AWSQLDBSession/Sources/AWSQLDBSession/Endpoints.swift
+++ b/Sources/Services/AWSQLDBSession/Sources/AWSQLDBSession/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSQLDBSession/Tests/AWSQLDBSessionTests/EndpointResolverTest.swift b/Sources/Services/AWSQLDBSession/Tests/AWSQLDBSessionTests/EndpointResolverTest.swift
index f1f354165fa..9fff615dfbb 100644
--- a/Sources/Services/AWSQLDBSession/Tests/AWSQLDBSessionTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSQLDBSession/Tests/AWSQLDBSessionTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSQLDBSession
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -530,7 +531,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -569,7 +570,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -608,7 +609,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -647,7 +648,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -688,7 +689,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSQuickSight/Sources/AWSQuickSight/Endpoints.swift b/Sources/Services/AWSQuickSight/Sources/AWSQuickSight/Endpoints.swift
index e27dada4882..60f6ba48ac2 100644
--- a/Sources/Services/AWSQuickSight/Sources/AWSQuickSight/Endpoints.swift
+++ b/Sources/Services/AWSQuickSight/Sources/AWSQuickSight/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSQuickSight/Tests/AWSQuickSightTests/EndpointResolverTest.swift b/Sources/Services/AWSQuickSight/Tests/AWSQuickSightTests/EndpointResolverTest.swift
index 56128490d3d..0582042ab76 100644
--- a/Sources/Services/AWSQuickSight/Tests/AWSQuickSightTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSQuickSight/Tests/AWSQuickSightTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSQuickSight
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -590,7 +591,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -629,7 +630,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -707,7 +708,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSRAM/Sources/AWSRAM/Endpoints.swift b/Sources/Services/AWSRAM/Sources/AWSRAM/Endpoints.swift
index 7cdae9c8c6b..e2e34abaac6 100644
--- a/Sources/Services/AWSRAM/Sources/AWSRAM/Endpoints.swift
+++ b/Sources/Services/AWSRAM/Sources/AWSRAM/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSRAM/Tests/AWSRAMTests/EndpointResolverTest.swift b/Sources/Services/AWSRAM/Tests/AWSRAMTests/EndpointResolverTest.swift
index 42d9bd9c804..9fa8e15fab4 100644
--- a/Sources/Services/AWSRAM/Tests/AWSRAMTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSRAM/Tests/AWSRAMTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSRAM
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSRDS/Sources/AWSRDS/Endpoints.swift b/Sources/Services/AWSRDS/Sources/AWSRDS/Endpoints.swift
index ca1de3db84c..edad7667086 100644
--- a/Sources/Services/AWSRDS/Sources/AWSRDS/Endpoints.swift
+++ b/Sources/Services/AWSRDS/Sources/AWSRDS/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSRDS/Tests/AWSRDSTests/EndpointResolverTest.swift b/Sources/Services/AWSRDS/Tests/AWSRDSTests/EndpointResolverTest.swift
index 2347b904ef8..e5e7726e924 100644
--- a/Sources/Services/AWSRDS/Tests/AWSRDSTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSRDS/Tests/AWSRDSTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSRDS
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -851,7 +852,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -890,7 +891,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -929,7 +930,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1028,7 +1029,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSRDSData/Sources/AWSRDSData/Endpoints.swift b/Sources/Services/AWSRDSData/Sources/AWSRDSData/Endpoints.swift
index 441e4ff38b7..b86af6b793c 100644
--- a/Sources/Services/AWSRDSData/Sources/AWSRDSData/Endpoints.swift
+++ b/Sources/Services/AWSRDSData/Sources/AWSRDSData/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSRDSData/Tests/AWSRDSDataTests/EndpointResolverTest.swift b/Sources/Services/AWSRDSData/Tests/AWSRDSDataTests/EndpointResolverTest.swift
index 6bcdd995b3b..171de11a567 100644
--- a/Sources/Services/AWSRDSData/Tests/AWSRDSDataTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSRDSData/Tests/AWSRDSDataTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSRDSData
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSRUM/Sources/AWSRUM/Endpoints.swift b/Sources/Services/AWSRUM/Sources/AWSRUM/Endpoints.swift
index a88937b1d48..97034e16d74 100644
--- a/Sources/Services/AWSRUM/Sources/AWSRUM/Endpoints.swift
+++ b/Sources/Services/AWSRUM/Sources/AWSRUM/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSRUM/Tests/AWSRUMTests/EndpointResolverTest.swift b/Sources/Services/AWSRUM/Tests/AWSRUMTests/EndpointResolverTest.swift
index ecec8cfb988..4b57a6d5d6a 100644
--- a/Sources/Services/AWSRUM/Tests/AWSRUMTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSRUM/Tests/AWSRUMTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSRUM
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -470,7 +471,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -509,7 +510,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -587,7 +588,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -608,7 +609,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSRbin/Sources/AWSRbin/Endpoints.swift b/Sources/Services/AWSRbin/Sources/AWSRbin/Endpoints.swift
index 1fefa5bdb4f..8eb7d013371 100644
--- a/Sources/Services/AWSRbin/Sources/AWSRbin/Endpoints.swift
+++ b/Sources/Services/AWSRbin/Sources/AWSRbin/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSRbin/Tests/AWSRbinTests/EndpointResolverTest.swift b/Sources/Services/AWSRbin/Tests/AWSRbinTests/EndpointResolverTest.swift
index 3c3b386eab3..48eda1a2204 100644
--- a/Sources/Services/AWSRbin/Tests/AWSRbinTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSRbin/Tests/AWSRbinTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSRbin
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -690,7 +691,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -729,7 +730,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -768,7 +769,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -807,7 +808,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -828,7 +829,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSRedshift/Sources/AWSRedshift/Endpoints.swift b/Sources/Services/AWSRedshift/Sources/AWSRedshift/Endpoints.swift
index eb006aa0290..ba270ba6aa1 100644
--- a/Sources/Services/AWSRedshift/Sources/AWSRedshift/Endpoints.swift
+++ b/Sources/Services/AWSRedshift/Sources/AWSRedshift/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSRedshift/Tests/AWSRedshiftTests/EndpointResolverTest.swift b/Sources/Services/AWSRedshift/Tests/AWSRedshiftTests/EndpointResolverTest.swift
index b22fa208cbb..b6b872d44c5 100644
--- a/Sources/Services/AWSRedshift/Tests/AWSRedshiftTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSRedshift/Tests/AWSRedshiftTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSRedshift
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -851,7 +852,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -890,7 +891,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -929,7 +930,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1028,7 +1029,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSRedshiftData/Sources/AWSRedshiftData/Endpoints.swift b/Sources/Services/AWSRedshiftData/Sources/AWSRedshiftData/Endpoints.swift
index 1e25d707c12..d88f1b891de 100644
--- a/Sources/Services/AWSRedshiftData/Sources/AWSRedshiftData/Endpoints.swift
+++ b/Sources/Services/AWSRedshiftData/Sources/AWSRedshiftData/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSRedshiftData/Tests/AWSRedshiftDataTests/EndpointResolverTest.swift b/Sources/Services/AWSRedshiftData/Tests/AWSRedshiftDataTests/EndpointResolverTest.swift
index edcc1241e4d..a6bc46d3319 100644
--- a/Sources/Services/AWSRedshiftData/Tests/AWSRedshiftDataTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSRedshiftData/Tests/AWSRedshiftDataTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSRedshiftData
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSRedshiftServerless/Sources/AWSRedshiftServerless/Endpoints.swift b/Sources/Services/AWSRedshiftServerless/Sources/AWSRedshiftServerless/Endpoints.swift
index eff78d4e6d9..18ea8d33069 100644
--- a/Sources/Services/AWSRedshiftServerless/Sources/AWSRedshiftServerless/Endpoints.swift
+++ b/Sources/Services/AWSRedshiftServerless/Sources/AWSRedshiftServerless/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSRedshiftServerless/Tests/AWSRedshiftServerlessTests/EndpointResolverTest.swift b/Sources/Services/AWSRedshiftServerless/Tests/AWSRedshiftServerlessTests/EndpointResolverTest.swift
index 656305a4986..86f3addbf24 100644
--- a/Sources/Services/AWSRedshiftServerless/Tests/AWSRedshiftServerlessTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSRedshiftServerless/Tests/AWSRedshiftServerlessTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSRedshiftServerless
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -490,7 +491,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -529,7 +530,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -607,7 +608,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -628,7 +629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -648,7 +649,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSRekognition/Sources/AWSRekognition/Endpoints.swift b/Sources/Services/AWSRekognition/Sources/AWSRekognition/Endpoints.swift
index 0fed8e939f3..278391d2492 100644
--- a/Sources/Services/AWSRekognition/Sources/AWSRekognition/Endpoints.swift
+++ b/Sources/Services/AWSRekognition/Sources/AWSRekognition/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSRekognition/Tests/AWSRekognitionTests/EndpointResolverTest.swift b/Sources/Services/AWSRekognition/Tests/AWSRekognitionTests/EndpointResolverTest.swift
index ccc19b12d04..2488fbad233 100644
--- a/Sources/Services/AWSRekognition/Tests/AWSRekognitionTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSRekognition/Tests/AWSRekognitionTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSRekognition
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -650,7 +651,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -689,7 +690,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -767,7 +768,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -788,7 +789,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -808,7 +809,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSRepostspace/Sources/AWSRepostspace/Endpoints.swift b/Sources/Services/AWSRepostspace/Sources/AWSRepostspace/Endpoints.swift
index 6808cb0b6c5..77357510d00 100644
--- a/Sources/Services/AWSRepostspace/Sources/AWSRepostspace/Endpoints.swift
+++ b/Sources/Services/AWSRepostspace/Sources/AWSRepostspace/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSRepostspace/Tests/AWSRepostspaceTests/EndpointResolverTest.swift b/Sources/Services/AWSRepostspace/Tests/AWSRepostspaceTests/EndpointResolverTest.swift
index 2f6843ea493..04a507c2fb7 100644
--- a/Sources/Services/AWSRepostspace/Tests/AWSRepostspaceTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSRepostspace/Tests/AWSRepostspaceTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSRepostspace
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSResiliencehub/Sources/AWSResiliencehub/Endpoints.swift b/Sources/Services/AWSResiliencehub/Sources/AWSResiliencehub/Endpoints.swift
index 466ac7658e6..85265722cc0 100644
--- a/Sources/Services/AWSResiliencehub/Sources/AWSResiliencehub/Endpoints.swift
+++ b/Sources/Services/AWSResiliencehub/Sources/AWSResiliencehub/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSResiliencehub/Tests/AWSResiliencehubTests/EndpointResolverTest.swift b/Sources/Services/AWSResiliencehub/Tests/AWSResiliencehubTests/EndpointResolverTest.swift
index b5fc709d202..158d0dc0596 100644
--- a/Sources/Services/AWSResiliencehub/Tests/AWSResiliencehubTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSResiliencehub/Tests/AWSResiliencehubTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSResiliencehub
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -670,7 +671,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -709,7 +710,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -787,7 +788,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -808,7 +809,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -828,7 +829,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSResourceExplorer2/Sources/AWSResourceExplorer2/Endpoints.swift b/Sources/Services/AWSResourceExplorer2/Sources/AWSResourceExplorer2/Endpoints.swift
index 02730eef9a1..0b26910bdb8 100644
--- a/Sources/Services/AWSResourceExplorer2/Sources/AWSResourceExplorer2/Endpoints.swift
+++ b/Sources/Services/AWSResourceExplorer2/Sources/AWSResourceExplorer2/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSResourceExplorer2/Tests/AWSResourceExplorer2Tests/EndpointResolverTest.swift b/Sources/Services/AWSResourceExplorer2/Tests/AWSResourceExplorer2Tests/EndpointResolverTest.swift
index 10ba436600c..ce9789b77e4 100644
--- a/Sources/Services/AWSResourceExplorer2/Tests/AWSResourceExplorer2Tests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSResourceExplorer2/Tests/AWSResourceExplorer2Tests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSResourceExplorer2
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSResourceGroups/Sources/AWSResourceGroups/Endpoints.swift b/Sources/Services/AWSResourceGroups/Sources/AWSResourceGroups/Endpoints.swift
index 0e7b097d3ee..6ba3205d796 100644
--- a/Sources/Services/AWSResourceGroups/Sources/AWSResourceGroups/Endpoints.swift
+++ b/Sources/Services/AWSResourceGroups/Sources/AWSResourceGroups/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSResourceGroups/Tests/AWSResourceGroupsTests/EndpointResolverTest.swift b/Sources/Services/AWSResourceGroups/Tests/AWSResourceGroupsTests/EndpointResolverTest.swift
index 597f7315098..426686256e3 100644
--- a/Sources/Services/AWSResourceGroups/Tests/AWSResourceGroupsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSResourceGroups/Tests/AWSResourceGroupsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSResourceGroups
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -830,7 +831,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -869,7 +870,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -947,7 +948,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSResourceGroupsTaggingAPI/Sources/AWSResourceGroupsTaggingAPI/Endpoints.swift b/Sources/Services/AWSResourceGroupsTaggingAPI/Sources/AWSResourceGroupsTaggingAPI/Endpoints.swift
index b7135318cbf..5b946add543 100644
--- a/Sources/Services/AWSResourceGroupsTaggingAPI/Sources/AWSResourceGroupsTaggingAPI/Endpoints.swift
+++ b/Sources/Services/AWSResourceGroupsTaggingAPI/Sources/AWSResourceGroupsTaggingAPI/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSResourceGroupsTaggingAPI/Tests/AWSResourceGroupsTaggingAPITests/EndpointResolverTest.swift b/Sources/Services/AWSResourceGroupsTaggingAPI/Tests/AWSResourceGroupsTaggingAPITests/EndpointResolverTest.swift
index eef5a4f9d25..683c772cfab 100644
--- a/Sources/Services/AWSResourceGroupsTaggingAPI/Tests/AWSResourceGroupsTaggingAPITests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSResourceGroupsTaggingAPI/Tests/AWSResourceGroupsTaggingAPITests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSResourceGroupsTaggingAPI
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -770,7 +771,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -809,7 +810,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSRoboMaker/Sources/AWSRoboMaker/Endpoints.swift b/Sources/Services/AWSRoboMaker/Sources/AWSRoboMaker/Endpoints.swift
index 97d8d77b574..f23ef6fc9aa 100644
--- a/Sources/Services/AWSRoboMaker/Sources/AWSRoboMaker/Endpoints.swift
+++ b/Sources/Services/AWSRoboMaker/Sources/AWSRoboMaker/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSRoboMaker/Tests/AWSRoboMakerTests/EndpointResolverTest.swift b/Sources/Services/AWSRoboMaker/Tests/AWSRoboMakerTests/EndpointResolverTest.swift
index be36c23f98c..a2b97f5052a 100644
--- a/Sources/Services/AWSRoboMaker/Tests/AWSRoboMakerTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSRoboMaker/Tests/AWSRoboMakerTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSRoboMaker
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -430,7 +431,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -469,7 +470,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -508,7 +509,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -547,7 +548,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -588,7 +589,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSRolesAnywhere/Sources/AWSRolesAnywhere/Endpoints.swift b/Sources/Services/AWSRolesAnywhere/Sources/AWSRolesAnywhere/Endpoints.swift
index 2e5422097d8..77a017e95a8 100644
--- a/Sources/Services/AWSRolesAnywhere/Sources/AWSRolesAnywhere/Endpoints.swift
+++ b/Sources/Services/AWSRolesAnywhere/Sources/AWSRolesAnywhere/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSRolesAnywhere/Tests/AWSRolesAnywhereTests/EndpointResolverTest.swift b/Sources/Services/AWSRolesAnywhere/Tests/AWSRolesAnywhereTests/EndpointResolverTest.swift
index d6125c532ea..30e2b56db29 100644
--- a/Sources/Services/AWSRolesAnywhere/Tests/AWSRolesAnywhereTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSRolesAnywhere/Tests/AWSRolesAnywhereTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSRolesAnywhere
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -650,7 +651,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -689,7 +690,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -767,7 +768,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -788,7 +789,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -808,7 +809,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSRoute53/Sources/AWSRoute53/Endpoints.swift b/Sources/Services/AWSRoute53/Sources/AWSRoute53/Endpoints.swift
index db448d5ac9f..f1f3885ee0b 100644
--- a/Sources/Services/AWSRoute53/Sources/AWSRoute53/Endpoints.swift
+++ b/Sources/Services/AWSRoute53/Sources/AWSRoute53/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSRoute53/Tests/AWSRoute53Tests/EndpointResolverTest.swift b/Sources/Services/AWSRoute53/Tests/AWSRoute53Tests/EndpointResolverTest.swift
index 66f0aee4ac1..fa2280a0c96 100644
--- a/Sources/Services/AWSRoute53/Tests/AWSRoute53Tests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSRoute53/Tests/AWSRoute53Tests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSRoute53
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,15 +32,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "route53",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -59,15 +60,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "route53",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,7 +88,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -107,15 +108,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "route53",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -135,7 +136,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -155,15 +156,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "route53",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -183,15 +184,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "route53",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,15 +272,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "route53",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -299,15 +300,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "route53",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -327,15 +328,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "route53",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -355,7 +356,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -375,15 +376,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "route53",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -403,7 +404,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -423,15 +424,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "route53",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,15 +452,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "route53",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -498,7 +499,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -537,15 +538,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "route53",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -565,15 +566,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "route53",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -612,7 +613,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,15 +652,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "route53",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -679,15 +680,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "route53",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -707,15 +708,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "route53",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -736,7 +737,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -756,7 +757,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSRoute53Domains/Sources/AWSRoute53Domains/Endpoints.swift b/Sources/Services/AWSRoute53Domains/Sources/AWSRoute53Domains/Endpoints.swift
index 32554bd1a15..07ad78cfc62 100644
--- a/Sources/Services/AWSRoute53Domains/Sources/AWSRoute53Domains/Endpoints.swift
+++ b/Sources/Services/AWSRoute53Domains/Sources/AWSRoute53Domains/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSRoute53Domains/Tests/AWSRoute53DomainsTests/EndpointResolverTest.swift b/Sources/Services/AWSRoute53Domains/Tests/AWSRoute53DomainsTests/EndpointResolverTest.swift
index 210d00c8e89..97922ee0e25 100644
--- a/Sources/Services/AWSRoute53Domains/Tests/AWSRoute53DomainsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSRoute53Domains/Tests/AWSRoute53DomainsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSRoute53Domains
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSRoute53Profiles/Sources/AWSRoute53Profiles/Endpoints.swift b/Sources/Services/AWSRoute53Profiles/Sources/AWSRoute53Profiles/Endpoints.swift
index 3b977530adc..28c94d57b4f 100644
--- a/Sources/Services/AWSRoute53Profiles/Sources/AWSRoute53Profiles/Endpoints.swift
+++ b/Sources/Services/AWSRoute53Profiles/Sources/AWSRoute53Profiles/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSRoute53Profiles/Tests/AWSRoute53ProfilesTests/EndpointResolverTest.swift b/Sources/Services/AWSRoute53Profiles/Tests/AWSRoute53ProfilesTests/EndpointResolverTest.swift
index 60b65e382b7..c909de0c750 100644
--- a/Sources/Services/AWSRoute53Profiles/Tests/AWSRoute53ProfilesTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSRoute53Profiles/Tests/AWSRoute53ProfilesTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSRoute53Profiles
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSRoute53RecoveryCluster/Sources/AWSRoute53RecoveryCluster/Endpoints.swift b/Sources/Services/AWSRoute53RecoveryCluster/Sources/AWSRoute53RecoveryCluster/Endpoints.swift
index 315db37b581..216a93c1ca1 100644
--- a/Sources/Services/AWSRoute53RecoveryCluster/Sources/AWSRoute53RecoveryCluster/Endpoints.swift
+++ b/Sources/Services/AWSRoute53RecoveryCluster/Sources/AWSRoute53RecoveryCluster/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSRoute53RecoveryCluster/Tests/AWSRoute53RecoveryClusterTests/EndpointResolverTest.swift b/Sources/Services/AWSRoute53RecoveryCluster/Tests/AWSRoute53RecoveryClusterTests/EndpointResolverTest.swift
index f0437391618..82362577954 100644
--- a/Sources/Services/AWSRoute53RecoveryCluster/Tests/AWSRoute53RecoveryClusterTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSRoute53RecoveryCluster/Tests/AWSRoute53RecoveryClusterTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSRoute53RecoveryCluster
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSRoute53RecoveryControlConfig/Sources/AWSRoute53RecoveryControlConfig/Endpoints.swift b/Sources/Services/AWSRoute53RecoveryControlConfig/Sources/AWSRoute53RecoveryControlConfig/Endpoints.swift
index e381380f51f..a48dde13896 100644
--- a/Sources/Services/AWSRoute53RecoveryControlConfig/Sources/AWSRoute53RecoveryControlConfig/Endpoints.swift
+++ b/Sources/Services/AWSRoute53RecoveryControlConfig/Sources/AWSRoute53RecoveryControlConfig/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSRoute53RecoveryControlConfig/Tests/AWSRoute53RecoveryControlConfigTests/EndpointResolverTest.swift b/Sources/Services/AWSRoute53RecoveryControlConfig/Tests/AWSRoute53RecoveryControlConfigTests/EndpointResolverTest.swift
index 47a73087b8c..95ebf4eb8fd 100644
--- a/Sources/Services/AWSRoute53RecoveryControlConfig/Tests/AWSRoute53RecoveryControlConfigTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSRoute53RecoveryControlConfig/Tests/AWSRoute53RecoveryControlConfigTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSRoute53RecoveryControlConfig
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,14 +88,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -114,14 +115,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -141,14 +142,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-west-2"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -168,14 +169,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-west-2"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -195,14 +196,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -222,14 +223,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -249,14 +250,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -276,14 +277,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -303,14 +304,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -330,14 +331,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -357,14 +358,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -384,14 +385,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -430,14 +431,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -476,14 +477,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -522,14 +523,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,14 +569,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -614,14 +615,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -660,14 +661,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -706,14 +707,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -752,14 +753,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSRoute53RecoveryReadiness/Sources/AWSRoute53RecoveryReadiness/Endpoints.swift b/Sources/Services/AWSRoute53RecoveryReadiness/Sources/AWSRoute53RecoveryReadiness/Endpoints.swift
index 4a3da79538a..9d44f90dca0 100644
--- a/Sources/Services/AWSRoute53RecoveryReadiness/Sources/AWSRoute53RecoveryReadiness/Endpoints.swift
+++ b/Sources/Services/AWSRoute53RecoveryReadiness/Sources/AWSRoute53RecoveryReadiness/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSRoute53RecoveryReadiness/Tests/AWSRoute53RecoveryReadinessTests/EndpointResolverTest.swift b/Sources/Services/AWSRoute53RecoveryReadiness/Tests/AWSRoute53RecoveryReadinessTests/EndpointResolverTest.swift
index 0dca380a895..46c5c2f6043 100644
--- a/Sources/Services/AWSRoute53RecoveryReadiness/Tests/AWSRoute53RecoveryReadinessTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSRoute53RecoveryReadiness/Tests/AWSRoute53RecoveryReadinessTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSRoute53RecoveryReadiness
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSRoute53Resolver/Sources/AWSRoute53Resolver/Endpoints.swift b/Sources/Services/AWSRoute53Resolver/Sources/AWSRoute53Resolver/Endpoints.swift
index d4c851f6ffe..b0fc3b41b9c 100644
--- a/Sources/Services/AWSRoute53Resolver/Sources/AWSRoute53Resolver/Endpoints.swift
+++ b/Sources/Services/AWSRoute53Resolver/Sources/AWSRoute53Resolver/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSRoute53Resolver/Tests/AWSRoute53ResolverTests/EndpointResolverTest.swift b/Sources/Services/AWSRoute53Resolver/Tests/AWSRoute53ResolverTests/EndpointResolverTest.swift
index 6a51ec44f78..c5a0326e487 100644
--- a/Sources/Services/AWSRoute53Resolver/Tests/AWSRoute53ResolverTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSRoute53Resolver/Tests/AWSRoute53ResolverTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSRoute53Resolver
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -790,7 +791,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -887,7 +888,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSS3/Sources/AWSS3/Endpoints.swift b/Sources/Services/AWSS3/Sources/AWSS3/Endpoints.swift
index a27f1b8b7db..9fa2fcac305 100644
--- a/Sources/Services/AWSS3/Sources/AWSS3/Endpoints.swift
+++ b/Sources/Services/AWSS3/Sources/AWSS3/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// When true, use S3 Accelerate. NOTE: Not all regions support S3 accelerate.
     public let accelerate: Swift.Bool
     /// The S3 bucket used to send the request. This is an optional parameter that will be set automatically for operations that are scoped to an S3 bucket.
diff --git a/Sources/Services/AWSS3/Tests/AWSS3Tests/EndpointResolverTest.swift b/Sources/Services/AWSS3/Tests/AWSS3Tests/EndpointResolverTest.swift
index a94fde142b9..7fbae6078ca 100644
--- a/Sources/Services/AWSS3/Tests/AWSS3Tests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSS3/Tests/AWSS3Tests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSS3
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -159,7 +160,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -167,8 +168,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -301,7 +302,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -309,8 +310,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -333,7 +334,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -341,8 +342,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -365,18 +366,18 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4a",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable],
+                        ],
                         "signingName": "s3",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -487,7 +488,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -495,8 +496,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -563,7 +564,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -571,8 +572,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -616,7 +617,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -624,8 +625,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -647,7 +648,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -655,8 +656,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -679,7 +680,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -687,8 +688,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -719,8 +720,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -743,7 +744,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -751,8 +752,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -797,7 +798,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -805,8 +806,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -852,7 +853,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -860,8 +861,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -885,7 +886,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -893,8 +894,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -913,7 +914,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -921,8 +922,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "disableDoubleEncoding": true,
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -941,7 +942,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -949,8 +950,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "disableDoubleEncoding": true,
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -969,7 +970,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -977,8 +978,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "disableDoubleEncoding": true,
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -997,7 +998,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1005,8 +1006,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "disableDoubleEncoding": true,
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1026,7 +1027,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1034,8 +1035,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "disableDoubleEncoding": true,
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1074,7 +1075,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1082,8 +1083,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1105,7 +1106,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1113,8 +1114,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1136,7 +1137,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1144,8 +1145,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "cn-north-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1167,7 +1168,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1175,8 +1176,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1198,7 +1199,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1206,8 +1207,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1229,7 +1230,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1237,8 +1238,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1261,7 +1262,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1269,8 +1270,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1293,7 +1294,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1301,8 +1302,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1324,7 +1325,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1332,8 +1333,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1354,7 +1355,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1362,8 +1363,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1384,7 +1385,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1392,8 +1393,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1414,7 +1415,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1422,8 +1423,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1444,7 +1445,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1452,8 +1453,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1474,7 +1475,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1482,8 +1483,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1506,7 +1507,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1514,8 +1515,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1537,7 +1538,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1545,8 +1546,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1570,7 +1571,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1578,8 +1579,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1603,7 +1604,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1611,8 +1612,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1634,7 +1635,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1642,8 +1643,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1665,7 +1666,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1673,8 +1674,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1696,7 +1697,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1704,8 +1705,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1727,7 +1728,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1735,8 +1736,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1759,7 +1760,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1767,8 +1768,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1791,7 +1792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1799,8 +1800,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1823,7 +1824,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1831,8 +1832,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1855,7 +1856,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1863,8 +1864,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1887,7 +1888,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1895,8 +1896,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1919,7 +1920,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1927,8 +1928,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1952,7 +1953,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1960,8 +1961,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1984,7 +1985,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1992,8 +1993,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2016,7 +2017,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2024,8 +2025,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true,
                         "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2048,7 +2049,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2056,8 +2057,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2081,7 +2082,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2089,8 +2090,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2114,7 +2115,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2122,8 +2123,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2147,7 +2148,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2155,8 +2156,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2180,7 +2181,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2188,8 +2189,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2214,7 +2215,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2222,8 +2223,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2246,7 +2247,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2254,16 +2255,16 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable],
+                        ],
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable],
+                    ],
                     [
                         "name": "sigv4",
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2301,7 +2302,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2309,8 +2310,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2333,7 +2334,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2341,8 +2342,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2423,7 +2424,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2431,8 +2432,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2471,7 +2472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2479,8 +2480,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2500,7 +2501,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2508,8 +2509,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2529,7 +2530,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2537,8 +2538,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2558,7 +2559,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2566,8 +2567,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2590,7 +2591,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2598,8 +2599,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "disableDoubleEncoding": true,
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2621,7 +2622,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2629,8 +2630,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "disableDoubleEncoding": true,
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2653,7 +2654,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2661,8 +2662,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "disableDoubleEncoding": true,
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2683,7 +2684,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2691,8 +2692,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "disableDoubleEncoding": true,
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2714,7 +2715,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2722,8 +2723,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "disableDoubleEncoding": true,
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2789,7 +2790,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2797,8 +2798,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "disableDoubleEncoding": true,
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2821,7 +2822,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2829,8 +2830,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "disableDoubleEncoding": true,
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2852,7 +2853,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2860,8 +2861,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "disableDoubleEncoding": true,
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2906,7 +2907,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2914,8 +2915,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "disableDoubleEncoding": true,
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2938,7 +2939,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2946,8 +2947,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "disableDoubleEncoding": true,
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2970,7 +2971,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2978,8 +2979,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "disableDoubleEncoding": true,
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3003,7 +3004,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3011,8 +3012,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "disableDoubleEncoding": true,
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3059,7 +3060,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3067,8 +3068,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "disableDoubleEncoding": true,
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3173,7 +3174,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3181,8 +3182,8 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4",
                         "signingName": "s3",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3205,7 +3206,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3213,8 +3214,8 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4",
                         "signingName": "s3",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3236,7 +3237,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3244,8 +3245,8 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4",
                         "signingName": "s3",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3264,7 +3265,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3272,8 +3273,8 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4",
                         "signingName": "s3",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3318,7 +3319,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3326,8 +3327,8 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4",
                         "signingName": "s3",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3370,7 +3371,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3378,8 +3379,8 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4",
                         "signingName": "s3",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3402,7 +3403,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3410,8 +3411,8 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4",
                         "signingName": "s3",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3471,7 +3472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3479,8 +3480,8 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4",
                         "signingName": "s3",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3520,7 +3521,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3528,8 +3529,8 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4",
                         "signingName": "s3",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3808,7 +3809,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3816,8 +3817,8 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4",
                         "signingName": "s3",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3838,7 +3839,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3846,8 +3847,8 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4",
                         "signingName": "s3",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3867,7 +3868,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3875,8 +3876,8 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4",
                         "signingName": "s3",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3897,7 +3898,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3905,8 +3906,8 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4",
                         "signingName": "s3",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3927,7 +3928,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3935,8 +3936,8 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4",
                         "signingName": "s3",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3958,7 +3959,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3966,8 +3967,8 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4",
                         "signingName": "s3",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3990,7 +3991,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3998,8 +3999,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4022,7 +4023,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4030,8 +4031,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4054,7 +4055,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4062,8 +4063,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4086,7 +4087,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4094,8 +4095,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4118,7 +4119,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4126,8 +4127,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4150,7 +4151,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4158,8 +4159,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4204,7 +4205,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4212,8 +4213,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "cn-north-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4236,7 +4237,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4244,8 +4245,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "cn-north-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4312,7 +4313,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4320,8 +4321,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4344,7 +4345,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4352,8 +4353,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4376,7 +4377,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4384,8 +4385,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4408,7 +4409,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4416,8 +4417,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4440,7 +4441,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4448,8 +4449,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4472,7 +4473,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4480,8 +4481,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4526,7 +4527,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4534,8 +4535,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4557,7 +4558,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4565,8 +4566,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingRegion": "us-gov-west-1",
                         "disableDoubleEncoding": true,
                         "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4611,7 +4612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4619,8 +4620,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4665,7 +4666,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4673,8 +4674,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4696,7 +4697,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4704,8 +4705,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4728,7 +4729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4736,8 +4737,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "cn-north-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4804,7 +4805,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4812,8 +4813,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "cn-north-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4858,7 +4859,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4866,8 +4867,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "cn-north-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4889,7 +4890,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4897,8 +4898,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "cn-north-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4921,7 +4922,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4929,8 +4930,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -4953,7 +4954,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -4961,8 +4962,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true,
                         "name": "sigv4"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5007,7 +5008,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -5015,8 +5016,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5061,7 +5062,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -5069,8 +5070,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5092,7 +5093,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -5100,8 +5101,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5125,7 +5126,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -5133,8 +5134,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5158,7 +5159,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -5166,8 +5167,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5260,7 +5261,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -5268,8 +5269,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5293,7 +5294,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -5301,8 +5302,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "cn-north-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5326,7 +5327,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -5334,8 +5335,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "cn-north-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5427,7 +5428,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -5435,8 +5436,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "cn-north-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5460,7 +5461,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -5468,8 +5469,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5493,7 +5494,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -5501,8 +5502,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5595,7 +5596,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -5603,8 +5604,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5627,7 +5628,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -5635,8 +5636,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5659,7 +5660,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -5667,8 +5668,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5713,7 +5714,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -5721,8 +5722,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5745,7 +5746,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -5753,8 +5754,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "cn-north-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5843,7 +5844,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -5851,8 +5852,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5875,7 +5876,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -5883,8 +5884,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5929,7 +5930,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -5937,8 +5938,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -5960,7 +5961,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -5968,16 +5969,16 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable],
+                        ],
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable],
+                    ],
                     [
                         "name": "sigv4",
                         "signingName": "s3-outposts",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6000,7 +6001,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -6008,16 +6009,16 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable],
+                        ],
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable],
+                    ],
                     [
                         "name": "sigv4",
                         "signingName": "s3-outposts",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6088,7 +6089,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -6096,16 +6097,16 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable],
+                        ],
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable],
+                    ],
                     [
                         "name": "sigv4",
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6128,7 +6129,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -6136,16 +6137,16 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable],
+                        ],
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable],
+                    ],
                     [
                         "name": "sigv4",
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6191,7 +6192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -6199,16 +6200,16 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable],
+                        ],
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable],
+                    ],
                     [
                         "name": "sigv4",
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6315,7 +6316,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -6323,8 +6324,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-object-lambda",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6347,7 +6348,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -6355,8 +6356,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-object-lambda",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6379,7 +6380,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -6387,8 +6388,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-object-lambda",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6411,7 +6412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -6419,8 +6420,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-object-lambda",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6443,7 +6444,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -6451,8 +6452,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-object-lambda",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6497,7 +6498,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -6505,8 +6506,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-object-lambda",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6595,7 +6596,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -6603,8 +6604,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-object-lambda",
                         "signingRegion": "us-gov-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6627,7 +6628,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -6635,8 +6636,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-object-lambda",
                         "signingRegion": "us-gov-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6902,7 +6903,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -6910,8 +6911,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-object-lambda",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6956,7 +6957,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -6964,8 +6965,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-object-lambda",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -6988,7 +6989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -6996,8 +6997,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-object-lambda",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7019,7 +7020,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7027,8 +7028,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-object-lambda",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7050,7 +7051,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7058,8 +7059,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-object-lambda",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7165,7 +7166,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7173,8 +7174,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-object-lambda",
                         "disableDoubleEncoding": true,
                         "signingRegion": "us-east.special"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7196,7 +7197,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7204,16 +7205,16 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable],
+                        ],
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable],
+                    ],
                     [
                         "name": "sigv4",
                         "signingName": "s3-outposts",
                         "signingRegion": "us-west-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7235,7 +7236,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7243,16 +7244,16 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable],
+                        ],
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable],
+                    ],
                     [
                         "name": "sigv4",
                         "signingName": "s3-outposts",
                         "signingRegion": "ap-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7274,7 +7275,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7282,16 +7283,16 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable],
+                        ],
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable],
+                    ],
                     [
                         "name": "sigv4",
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7313,7 +7314,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7321,16 +7322,16 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable],
+                        ],
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable],
+                    ],
                     [
                         "name": "sigv4",
                         "signingName": "s3-outposts",
                         "signingRegion": "me-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7353,7 +7354,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7361,16 +7362,16 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable],
+                        ],
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable],
+                    ],
                     [
                         "name": "sigv4",
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7393,7 +7394,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7401,16 +7402,16 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable],
+                        ],
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable],
+                    ],
                     [
                         "name": "sigv4",
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7517,7 +7518,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7525,8 +7526,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "snow",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7548,7 +7549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7556,8 +7557,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "snow",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7580,7 +7581,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7588,8 +7589,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "snow",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7612,7 +7613,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7620,8 +7621,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "snow",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -7644,7 +7645,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7652,8 +7653,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -7677,7 +7678,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7685,8 +7686,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "cn-north-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -7710,7 +7711,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7718,8 +7719,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -7743,7 +7744,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7751,8 +7752,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "cn-north-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -7776,7 +7777,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7784,8 +7785,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -7809,7 +7810,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7817,8 +7818,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -7842,7 +7843,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7850,8 +7851,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -7875,7 +7876,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7883,8 +7884,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -7908,7 +7909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7916,8 +7917,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -7941,7 +7942,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7949,8 +7950,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -7974,7 +7975,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -7982,8 +7983,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8029,7 +8030,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8037,8 +8038,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8084,7 +8085,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8092,8 +8093,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8117,7 +8118,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8125,8 +8126,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8150,7 +8151,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8158,8 +8159,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8183,7 +8184,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8191,8 +8192,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8216,7 +8217,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8224,8 +8225,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8249,7 +8250,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8257,8 +8258,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8282,7 +8283,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8290,8 +8291,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8315,7 +8316,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8323,8 +8324,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8348,7 +8349,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8356,8 +8357,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8381,7 +8382,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8389,8 +8390,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8415,7 +8416,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8423,8 +8424,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8449,7 +8450,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8457,8 +8458,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "cn-north-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8483,7 +8484,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8491,8 +8492,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8539,7 +8540,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8547,8 +8548,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8572,7 +8573,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8580,8 +8581,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8605,7 +8606,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8613,8 +8614,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8638,7 +8639,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8646,8 +8647,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8671,7 +8672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8679,8 +8680,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8704,7 +8705,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8712,8 +8713,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8737,7 +8738,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8745,8 +8746,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8770,7 +8771,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8778,8 +8779,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8803,7 +8804,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8811,8 +8812,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8836,7 +8837,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8844,8 +8845,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8870,7 +8871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8878,8 +8879,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8904,7 +8905,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8912,8 +8913,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8938,7 +8939,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8946,8 +8947,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -8972,7 +8973,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -8980,8 +8981,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -9006,7 +9007,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -9014,8 +9015,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -9040,7 +9041,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -9048,8 +9049,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -9074,7 +9075,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -9082,8 +9083,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -9108,7 +9109,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -9116,8 +9117,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -9142,7 +9143,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -9150,8 +9151,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -9176,7 +9177,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -9184,8 +9185,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -9210,7 +9211,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -9218,8 +9219,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -9244,7 +9245,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -9252,8 +9253,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -9279,7 +9280,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -9287,8 +9288,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -9314,7 +9315,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -9322,8 +9323,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -9348,7 +9349,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -9356,8 +9357,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -9381,7 +9382,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -9389,8 +9390,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -9414,7 +9415,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -9422,8 +9423,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -9449,7 +9450,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -9457,8 +9458,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -9484,7 +9485,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -9492,8 +9493,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -9517,7 +9518,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -9525,8 +9526,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
@@ -9550,7 +9551,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -9558,8 +9559,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable],
+                    ]
+                ],
                 "backend": "S3Express"
             ]
 
diff --git a/Sources/Services/AWSS3Control/Sources/AWSS3Control/Endpoints.swift b/Sources/Services/AWSS3Control/Sources/AWSS3Control/Endpoints.swift
index 427b6828453..362f3e0f13a 100644
--- a/Sources/Services/AWSS3Control/Sources/AWSS3Control/Endpoints.swift
+++ b/Sources/Services/AWSS3Control/Sources/AWSS3Control/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// The S3 AccessPointName used to send the request. This is an optional parameter that will be set automatically for operations that are scoped to an S3 AccessPoint.
     public let accessPointName: Swift.String?
     /// The Account ID used to send the request. This is an optional parameter that will be set automatically for operations that require it.
diff --git a/Sources/Services/AWSS3Control/Tests/AWSS3ControlTests/EndpointResolverTest.swift b/Sources/Services/AWSS3Control/Tests/AWSS3ControlTests/EndpointResolverTest.swift
index c25645f7446..e32166fb7b4 100644
--- a/Sources/Services/AWSS3Control/Tests/AWSS3ControlTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSS3Control/Tests/AWSS3ControlTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSS3Control
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -34,7 +35,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -42,8 +43,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -68,7 +69,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -76,8 +77,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -102,7 +103,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -110,8 +111,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -136,7 +137,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -144,8 +145,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "cn-north-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -170,7 +171,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -178,8 +179,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -204,7 +205,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -212,8 +213,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -238,7 +239,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -246,8 +247,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-gov-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -272,7 +273,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -280,8 +281,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "cn-north-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -328,7 +329,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -336,8 +337,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-gov-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -362,7 +363,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -370,8 +371,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -396,7 +397,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -404,8 +405,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -430,7 +431,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -438,8 +439,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-gov-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -464,7 +465,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -472,8 +473,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -496,7 +497,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -504,8 +505,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -527,7 +528,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -535,8 +536,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -559,7 +560,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -567,8 +568,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -590,7 +591,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -598,8 +599,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -622,7 +623,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -630,8 +631,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -654,7 +655,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -662,8 +663,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -688,7 +689,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -696,8 +697,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -722,7 +723,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -730,8 +731,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -820,7 +821,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -828,8 +829,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -853,7 +854,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -861,8 +862,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -911,7 +912,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -919,8 +920,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -944,7 +945,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -952,8 +953,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -1023,7 +1024,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1031,8 +1032,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1055,7 +1056,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1063,8 +1064,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -1090,7 +1091,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1098,8 +1099,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1123,7 +1124,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1131,8 +1132,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1155,7 +1156,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1163,8 +1164,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1188,7 +1189,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1196,8 +1197,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1241,7 +1242,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1249,8 +1250,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -1274,7 +1275,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1282,8 +1283,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -1307,7 +1308,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1315,8 +1316,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-gov-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -1340,7 +1341,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1348,8 +1349,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-gov-west-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -1373,7 +1374,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1381,8 +1382,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -1406,7 +1407,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1414,8 +1415,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -1439,7 +1440,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1447,8 +1448,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "cn-north-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -1472,7 +1473,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1480,8 +1481,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -1505,7 +1506,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1513,8 +1514,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-gov-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -1538,7 +1539,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1546,8 +1547,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-gov-west-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -1571,7 +1572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1579,8 +1580,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -1604,7 +1605,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1612,8 +1613,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -1637,7 +1638,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1645,8 +1646,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "af-south-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -1670,7 +1671,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1678,8 +1679,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -1703,7 +1704,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1711,8 +1712,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-gov-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -1736,7 +1737,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1744,8 +1745,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-gov-west-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -1769,7 +1770,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1777,8 +1778,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -1886,7 +1887,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1894,8 +1895,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1917,7 +1918,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1925,8 +1926,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1948,7 +1949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1956,8 +1957,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1979,7 +1980,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1987,8 +1988,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2006,7 +2007,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2014,8 +2015,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2034,7 +2035,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2042,8 +2043,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2062,7 +2063,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2070,8 +2071,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2091,7 +2092,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2099,8 +2100,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2118,7 +2119,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2126,8 +2127,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "cn-north-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2168,7 +2169,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2176,8 +2177,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2220,7 +2221,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2228,8 +2229,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2251,7 +2252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2259,8 +2260,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2281,7 +2282,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2289,8 +2290,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2369,7 +2370,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2377,8 +2378,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2398,7 +2399,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2406,8 +2407,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2427,7 +2428,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2435,8 +2436,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2619,7 +2620,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2627,8 +2628,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2651,7 +2652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2659,8 +2660,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -2816,7 +2817,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2824,8 +2825,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -2894,7 +2895,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2902,8 +2903,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -2927,7 +2928,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -2935,8 +2936,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -3028,7 +3029,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3036,8 +3037,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3-outposts",
                         "signingRegion": "us-west-2",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         var headers = SmithyHTTPAPI.Headers()
@@ -3061,7 +3062,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3069,8 +3070,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "snow",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3091,7 +3092,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3099,8 +3100,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "snow",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3122,7 +3123,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3130,8 +3131,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "snow",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3153,7 +3154,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3161,8 +3162,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3",
                         "signingRegion": "snow",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3227,7 +3228,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3235,8 +3236,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3259,7 +3260,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3267,8 +3268,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3291,7 +3292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3299,8 +3300,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3323,7 +3324,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3331,8 +3332,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "us-east-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3355,7 +3356,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3363,8 +3364,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "cn-north-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -3387,7 +3388,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -3395,8 +3396,8 @@ class EndpointResolverTest: XCTestCase {
                         "signingName": "s3express",
                         "signingRegion": "cn-north-1",
                         "disableDoubleEncoding": true
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSS3Outposts/Sources/AWSS3Outposts/Endpoints.swift b/Sources/Services/AWSS3Outposts/Sources/AWSS3Outposts/Endpoints.swift
index 486c419c5c2..0445dc6faf9 100644
--- a/Sources/Services/AWSS3Outposts/Sources/AWSS3Outposts/Endpoints.swift
+++ b/Sources/Services/AWSS3Outposts/Sources/AWSS3Outposts/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSS3Outposts/Tests/AWSS3OutpostsTests/EndpointResolverTest.swift b/Sources/Services/AWSS3Outposts/Tests/AWSS3OutpostsTests/EndpointResolverTest.swift
index a06b0b5b844..d48b071a335 100644
--- a/Sources/Services/AWSS3Outposts/Tests/AWSS3OutpostsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSS3Outposts/Tests/AWSS3OutpostsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSS3Outposts
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -690,7 +691,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -729,7 +730,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -768,7 +769,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -807,7 +808,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -828,7 +829,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSS3Tables/Sources/AWSS3Tables/Endpoints.swift b/Sources/Services/AWSS3Tables/Sources/AWSS3Tables/Endpoints.swift
index 3f2d98ea2b3..d002b0cfa52 100644
--- a/Sources/Services/AWSS3Tables/Sources/AWSS3Tables/Endpoints.swift
+++ b/Sources/Services/AWSS3Tables/Sources/AWSS3Tables/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSS3Tables/Tests/AWSS3TablesTests/EndpointResolverTest.swift b/Sources/Services/AWSS3Tables/Tests/AWSS3TablesTests/EndpointResolverTest.swift
index 28dc6ce0080..1e203834879 100644
--- a/Sources/Services/AWSS3Tables/Tests/AWSS3TablesTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSS3Tables/Tests/AWSS3TablesTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSS3Tables
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSES/Sources/AWSSES/Endpoints.swift b/Sources/Services/AWSSES/Sources/AWSSES/Endpoints.swift
index f2eeefd56a9..b276839b3a6 100644
--- a/Sources/Services/AWSSES/Sources/AWSSES/Endpoints.swift
+++ b/Sources/Services/AWSSES/Sources/AWSSES/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSES/Tests/AWSSESTests/EndpointResolverTest.swift b/Sources/Services/AWSSES/Tests/AWSSESTests/EndpointResolverTest.swift
index b4af0fd39b1..571f4d9ded6 100644
--- a/Sources/Services/AWSSES/Tests/AWSSESTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSES/Tests/AWSSESTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSES
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -730,7 +731,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -769,7 +770,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -808,7 +809,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -847,7 +848,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -868,7 +869,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSESv2/Sources/AWSSESv2/Endpoints.swift b/Sources/Services/AWSSESv2/Sources/AWSSESv2/Endpoints.swift
index 58b4750159d..4dc3f04fd6f 100644
--- a/Sources/Services/AWSSESv2/Sources/AWSSESv2/Endpoints.swift
+++ b/Sources/Services/AWSSESv2/Sources/AWSSESv2/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// Operation parameter for EndpointId
diff --git a/Sources/Services/AWSSESv2/Tests/AWSSESv2Tests/EndpointResolverTest.swift b/Sources/Services/AWSSESv2/Tests/AWSSESv2Tests/EndpointResolverTest.swift
index dcf377ff252..81c0d8c1a96 100644
--- a/Sources/Services/AWSSESv2/Tests/AWSSESv2Tests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSESv2/Tests/AWSSESv2Tests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSESv2
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -730,7 +731,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -769,7 +770,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -808,7 +809,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -847,7 +848,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -868,7 +869,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -965,7 +966,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -973,9 +974,9 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4a",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable]
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        ]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -996,7 +997,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1004,9 +1005,9 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4a",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable]
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        ]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1065,7 +1066,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1124,7 +1125,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
@@ -1132,9 +1133,9 @@ class EndpointResolverTest: XCTestCase {
                         "name": "sigv4a",
                         "signingRegionSet": [
                             "*"
-                        ] as [AnyHashable]
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                        ]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSFN/Sources/AWSSFN/Endpoints.swift b/Sources/Services/AWSSFN/Sources/AWSSFN/Endpoints.swift
index be289ad912c..6caf0ea776c 100644
--- a/Sources/Services/AWSSFN/Sources/AWSSFN/Endpoints.swift
+++ b/Sources/Services/AWSSFN/Sources/AWSSFN/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSFN/Tests/AWSSFNTests/EndpointResolverTest.swift b/Sources/Services/AWSSFN/Tests/AWSSFNTests/EndpointResolverTest.swift
index f2f51342d96..c015d535b2a 100644
--- a/Sources/Services/AWSSFN/Tests/AWSSFNTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSFN/Tests/AWSSFNTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSFN
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSMS/Sources/AWSSMS/Endpoints.swift b/Sources/Services/AWSSMS/Sources/AWSSMS/Endpoints.swift
index 9a890c6d62d..594f541c9b8 100644
--- a/Sources/Services/AWSSMS/Sources/AWSSMS/Endpoints.swift
+++ b/Sources/Services/AWSSMS/Sources/AWSSMS/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSMS/Tests/AWSSMSTests/EndpointResolverTest.swift b/Sources/Services/AWSSMS/Tests/AWSSMSTests/EndpointResolverTest.swift
index 93b9e82d179..2470acf43dd 100644
--- a/Sources/Services/AWSSMS/Tests/AWSSMSTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSMS/Tests/AWSSMSTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSMS
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -790,7 +791,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -829,7 +830,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -868,7 +869,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -907,7 +908,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSNS/Sources/AWSSNS/Endpoints.swift b/Sources/Services/AWSSNS/Sources/AWSSNS/Endpoints.swift
index b2e1700f513..ddd0eb66a4d 100644
--- a/Sources/Services/AWSSNS/Sources/AWSSNS/Endpoints.swift
+++ b/Sources/Services/AWSSNS/Sources/AWSSNS/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSNS/Tests/AWSSNSTests/EndpointResolverTest.swift b/Sources/Services/AWSSNS/Tests/AWSSNSTests/EndpointResolverTest.swift
index 0a5f244ed79..3449d04eb29 100644
--- a/Sources/Services/AWSSNS/Tests/AWSSNSTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSNS/Tests/AWSSNSTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSNS
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSQS/Sources/AWSSQS/Endpoints.swift b/Sources/Services/AWSSQS/Sources/AWSSQS/Endpoints.swift
index 0e1b88101ba..f5995f4a8b5 100644
--- a/Sources/Services/AWSSQS/Sources/AWSSQS/Endpoints.swift
+++ b/Sources/Services/AWSSQS/Sources/AWSSQS/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSQS/Tests/AWSSQSTests/EndpointResolverTest.swift b/Sources/Services/AWSSQS/Tests/AWSSQSTests/EndpointResolverTest.swift
index a9f347a407a..00b31bdb4a2 100644
--- a/Sources/Services/AWSSQS/Tests/AWSSQSTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSQS/Tests/AWSSQSTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSQS
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -850,7 +851,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -889,7 +890,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSSM/Sources/AWSSSM/Endpoints.swift b/Sources/Services/AWSSSM/Sources/AWSSSM/Endpoints.swift
index 52a0880cebd..f8439244487 100644
--- a/Sources/Services/AWSSSM/Sources/AWSSSM/Endpoints.swift
+++ b/Sources/Services/AWSSSM/Sources/AWSSSM/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSSM/Tests/AWSSSMTests/EndpointResolverTest.swift b/Sources/Services/AWSSSM/Tests/AWSSSMTests/EndpointResolverTest.swift
index e496d104805..da1d74f7d56 100644
--- a/Sources/Services/AWSSSM/Tests/AWSSSMTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSSM/Tests/AWSSSMTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSSM
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSSMContacts/Sources/AWSSSMContacts/Endpoints.swift b/Sources/Services/AWSSSMContacts/Sources/AWSSSMContacts/Endpoints.swift
index 92e9de047ed..061a3be91d1 100644
--- a/Sources/Services/AWSSSMContacts/Sources/AWSSSMContacts/Endpoints.swift
+++ b/Sources/Services/AWSSSMContacts/Sources/AWSSSMContacts/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSSMContacts/Tests/AWSSSMContactsTests/EndpointResolverTest.swift b/Sources/Services/AWSSSMContacts/Tests/AWSSSMContactsTests/EndpointResolverTest.swift
index da10abc551f..f41b65d18b9 100644
--- a/Sources/Services/AWSSSMContacts/Tests/AWSSSMContactsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSSMContacts/Tests/AWSSSMContactsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSSMContacts
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSSMIncidents/Sources/AWSSSMIncidents/Endpoints.swift b/Sources/Services/AWSSSMIncidents/Sources/AWSSSMIncidents/Endpoints.swift
index d74e86c13fe..bd207b83948 100644
--- a/Sources/Services/AWSSSMIncidents/Sources/AWSSSMIncidents/Endpoints.swift
+++ b/Sources/Services/AWSSSMIncidents/Sources/AWSSSMIncidents/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSSMIncidents/Tests/AWSSSMIncidentsTests/EndpointResolverTest.swift b/Sources/Services/AWSSSMIncidents/Tests/AWSSSMIncidentsTests/EndpointResolverTest.swift
index 60b5c4f5830..51f90bb8269 100644
--- a/Sources/Services/AWSSSMIncidents/Tests/AWSSSMIncidentsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSSMIncidents/Tests/AWSSSMIncidentsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSSMIncidents
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -590,7 +591,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -629,7 +630,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -707,7 +708,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSSMQuickSetup/Sources/AWSSSMQuickSetup/Endpoints.swift b/Sources/Services/AWSSSMQuickSetup/Sources/AWSSSMQuickSetup/Endpoints.swift
index 3c3dc13b575..e8f51ab17cf 100644
--- a/Sources/Services/AWSSSMQuickSetup/Sources/AWSSSMQuickSetup/Endpoints.swift
+++ b/Sources/Services/AWSSSMQuickSetup/Sources/AWSSSMQuickSetup/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSSMQuickSetup/Tests/AWSSSMQuickSetupTests/EndpointResolverTest.swift b/Sources/Services/AWSSSMQuickSetup/Tests/AWSSSMQuickSetupTests/EndpointResolverTest.swift
index 8914ef1fed3..bc1905c469e 100644
--- a/Sources/Services/AWSSSMQuickSetup/Tests/AWSSSMQuickSetupTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSSMQuickSetup/Tests/AWSSSMQuickSetupTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSSMQuickSetup
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSSO/Sources/AWSSSO/Endpoints.swift b/Sources/Services/AWSSSO/Sources/AWSSSO/Endpoints.swift
index f57884224db..6c27b740d42 100644
--- a/Sources/Services/AWSSSO/Sources/AWSSSO/Endpoints.swift
+++ b/Sources/Services/AWSSSO/Sources/AWSSSO/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSSO/Tests/AWSSSOTests/EndpointResolverTest.swift b/Sources/Services/AWSSSO/Tests/AWSSSOTests/EndpointResolverTest.swift
index 1aca0524270..2e40e575aa7 100644
--- a/Sources/Services/AWSSSO/Tests/AWSSSOTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSSO/Tests/AWSSSOTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSSO
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -670,7 +671,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -709,7 +710,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -787,7 +788,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -808,7 +809,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -828,7 +829,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSSOAdmin/Sources/AWSSSOAdmin/Endpoints.swift b/Sources/Services/AWSSSOAdmin/Sources/AWSSSOAdmin/Endpoints.swift
index 1eee104ca28..f45958df41f 100644
--- a/Sources/Services/AWSSSOAdmin/Sources/AWSSSOAdmin/Endpoints.swift
+++ b/Sources/Services/AWSSSOAdmin/Sources/AWSSSOAdmin/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSSOAdmin/Tests/AWSSSOAdminTests/EndpointResolverTest.swift b/Sources/Services/AWSSSOAdmin/Tests/AWSSSOAdminTests/EndpointResolverTest.swift
index a79f31093dc..59b26736a49 100644
--- a/Sources/Services/AWSSSOAdmin/Tests/AWSSSOAdminTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSSOAdmin/Tests/AWSSSOAdminTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSSOAdmin
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -690,7 +691,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -729,7 +730,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -768,7 +769,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -807,7 +808,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -828,7 +829,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSSOOIDC/Sources/AWSSSOOIDC/Endpoints.swift b/Sources/Services/AWSSSOOIDC/Sources/AWSSSOOIDC/Endpoints.swift
index a1fdbab2c13..a1a68bac0e9 100644
--- a/Sources/Services/AWSSSOOIDC/Sources/AWSSSOOIDC/Endpoints.swift
+++ b/Sources/Services/AWSSSOOIDC/Sources/AWSSSOOIDC/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSSOOIDC/Tests/AWSSSOOIDCTests/EndpointResolverTest.swift b/Sources/Services/AWSSSOOIDC/Tests/AWSSSOOIDCTests/EndpointResolverTest.swift
index 9519746e530..2f90e5a4981 100644
--- a/Sources/Services/AWSSSOOIDC/Tests/AWSSSOOIDCTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSSOOIDC/Tests/AWSSSOOIDCTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSSOOIDC
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -670,7 +671,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -709,7 +710,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -787,7 +788,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -808,7 +809,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -828,7 +829,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSTS/Sources/AWSSTS/Endpoints.swift b/Sources/Services/AWSSTS/Sources/AWSSTS/Endpoints.swift
index 670402380aa..bc046ec81a3 100644
--- a/Sources/Services/AWSSTS/Sources/AWSSTS/Endpoints.swift
+++ b/Sources/Services/AWSSTS/Sources/AWSSTS/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSTS/Tests/AWSSTSTests/EndpointResolverTest.swift b/Sources/Services/AWSSTS/Tests/AWSSTSTests/EndpointResolverTest.swift
index 675d92175ee..fa4da7d3f40 100644
--- a/Sources/Services/AWSSTS/Tests/AWSSTSTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSTS/Tests/AWSSTSTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSTS
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,15 +212,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "sts",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -239,7 +240,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -259,7 +260,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -279,7 +280,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -299,7 +300,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -319,7 +320,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -339,7 +340,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -359,7 +360,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -379,7 +380,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -399,7 +400,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -419,7 +420,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -439,7 +440,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -459,7 +460,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -479,7 +480,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -499,7 +500,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -519,7 +520,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -539,7 +540,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -559,7 +560,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -579,7 +580,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -599,7 +600,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -619,7 +620,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -639,7 +640,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -659,7 +660,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -679,7 +680,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -699,7 +700,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -719,7 +720,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -739,7 +740,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -759,7 +760,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -779,7 +780,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -799,7 +800,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -819,7 +820,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -839,7 +840,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -859,7 +860,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -898,7 +899,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -937,7 +938,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -976,7 +977,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1016,7 +1017,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1036,7 +1037,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1113,15 +1114,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "sts",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1142,15 +1143,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "sts",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1171,15 +1172,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "sts",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1200,15 +1201,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "sts",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1229,15 +1230,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "sts",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1258,15 +1259,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "sts",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1287,15 +1288,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "sts",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1316,15 +1317,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "sts",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1345,15 +1346,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "sts",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1374,15 +1375,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "sts",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1403,15 +1404,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "sts",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1432,15 +1433,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "sts",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1461,15 +1462,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "sts",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1490,15 +1491,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "sts",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1519,15 +1520,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "sts",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1548,15 +1549,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "sts",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1577,15 +1578,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "sts",
                         "signingRegion": "us-east-3"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1607,7 +1608,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1628,7 +1629,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSWF/Sources/AWSSWF/Endpoints.swift b/Sources/Services/AWSSWF/Sources/AWSSWF/Endpoints.swift
index d712ac22c8e..f58a52e7526 100644
--- a/Sources/Services/AWSSWF/Sources/AWSSWF/Endpoints.swift
+++ b/Sources/Services/AWSSWF/Sources/AWSSWF/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSWF/Tests/AWSSWFTests/EndpointResolverTest.swift b/Sources/Services/AWSSWF/Tests/AWSSWFTests/EndpointResolverTest.swift
index b059103fb67..e7dd38cee84 100644
--- a/Sources/Services/AWSSWF/Tests/AWSSWFTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSWF/Tests/AWSSWFTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSWF
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -909,7 +910,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSageMaker/Sources/AWSSageMaker/Endpoints.swift b/Sources/Services/AWSSageMaker/Sources/AWSSageMaker/Endpoints.swift
index a56855e2de1..3a812447c77 100644
--- a/Sources/Services/AWSSageMaker/Sources/AWSSageMaker/Endpoints.swift
+++ b/Sources/Services/AWSSageMaker/Sources/AWSSageMaker/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSageMaker/Tests/AWSSageMakerTests/EndpointResolverTest.swift b/Sources/Services/AWSSageMaker/Tests/AWSSageMakerTests/EndpointResolverTest.swift
index 082d4f6b489..1419cf73b2d 100644
--- a/Sources/Services/AWSSageMaker/Tests/AWSSageMakerTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSageMaker/Tests/AWSSageMakerTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSageMaker
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -830,7 +831,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -927,7 +928,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSageMakerA2IRuntime/Sources/AWSSageMakerA2IRuntime/Endpoints.swift b/Sources/Services/AWSSageMakerA2IRuntime/Sources/AWSSageMakerA2IRuntime/Endpoints.swift
index 67f9015dec0..e6db17228bf 100644
--- a/Sources/Services/AWSSageMakerA2IRuntime/Sources/AWSSageMakerA2IRuntime/Endpoints.swift
+++ b/Sources/Services/AWSSageMakerA2IRuntime/Sources/AWSSageMakerA2IRuntime/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSageMakerA2IRuntime/Tests/AWSSageMakerA2IRuntimeTests/EndpointResolverTest.swift b/Sources/Services/AWSSageMakerA2IRuntime/Tests/AWSSageMakerA2IRuntimeTests/EndpointResolverTest.swift
index 76df9b03890..d1f8e975ee2 100644
--- a/Sources/Services/AWSSageMakerA2IRuntime/Tests/AWSSageMakerA2IRuntimeTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSageMakerA2IRuntime/Tests/AWSSageMakerA2IRuntimeTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSageMakerA2IRuntime
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSageMakerFeatureStoreRuntime/Sources/AWSSageMakerFeatureStoreRuntime/Endpoints.swift b/Sources/Services/AWSSageMakerFeatureStoreRuntime/Sources/AWSSageMakerFeatureStoreRuntime/Endpoints.swift
index b545e4b921e..6eb1c599dca 100644
--- a/Sources/Services/AWSSageMakerFeatureStoreRuntime/Sources/AWSSageMakerFeatureStoreRuntime/Endpoints.swift
+++ b/Sources/Services/AWSSageMakerFeatureStoreRuntime/Sources/AWSSageMakerFeatureStoreRuntime/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSageMakerFeatureStoreRuntime/Tests/AWSSageMakerFeatureStoreRuntimeTests/EndpointResolverTest.swift b/Sources/Services/AWSSageMakerFeatureStoreRuntime/Tests/AWSSageMakerFeatureStoreRuntimeTests/EndpointResolverTest.swift
index 60eb962bf6b..44766728624 100644
--- a/Sources/Services/AWSSageMakerFeatureStoreRuntime/Tests/AWSSageMakerFeatureStoreRuntimeTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSageMakerFeatureStoreRuntime/Tests/AWSSageMakerFeatureStoreRuntimeTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSageMakerFeatureStoreRuntime
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSageMakerGeospatial/Sources/AWSSageMakerGeospatial/Endpoints.swift b/Sources/Services/AWSSageMakerGeospatial/Sources/AWSSageMakerGeospatial/Endpoints.swift
index 25b60a463ec..77d33502c1d 100644
--- a/Sources/Services/AWSSageMakerGeospatial/Sources/AWSSageMakerGeospatial/Endpoints.swift
+++ b/Sources/Services/AWSSageMakerGeospatial/Sources/AWSSageMakerGeospatial/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSageMakerGeospatial/Tests/AWSSageMakerGeospatialTests/EndpointResolverTest.swift b/Sources/Services/AWSSageMakerGeospatial/Tests/AWSSageMakerGeospatialTests/EndpointResolverTest.swift
index 3d08a94d5ce..5385aac50b0 100644
--- a/Sources/Services/AWSSageMakerGeospatial/Tests/AWSSageMakerGeospatialTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSageMakerGeospatial/Tests/AWSSageMakerGeospatialTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSageMakerGeospatial
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSageMakerMetrics/Sources/AWSSageMakerMetrics/Endpoints.swift b/Sources/Services/AWSSageMakerMetrics/Sources/AWSSageMakerMetrics/Endpoints.swift
index c012473ec04..3b041ed5d35 100644
--- a/Sources/Services/AWSSageMakerMetrics/Sources/AWSSageMakerMetrics/Endpoints.swift
+++ b/Sources/Services/AWSSageMakerMetrics/Sources/AWSSageMakerMetrics/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSageMakerMetrics/Tests/AWSSageMakerMetricsTests/EndpointResolverTest.swift b/Sources/Services/AWSSageMakerMetrics/Tests/AWSSageMakerMetricsTests/EndpointResolverTest.swift
index 218c9b3d9c8..72798036106 100644
--- a/Sources/Services/AWSSageMakerMetrics/Tests/AWSSageMakerMetricsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSageMakerMetrics/Tests/AWSSageMakerMetricsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSageMakerMetrics
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSageMakerRuntime/Sources/AWSSageMakerRuntime/Endpoints.swift b/Sources/Services/AWSSageMakerRuntime/Sources/AWSSageMakerRuntime/Endpoints.swift
index d7d0d803f32..ced6d2d0594 100644
--- a/Sources/Services/AWSSageMakerRuntime/Sources/AWSSageMakerRuntime/Endpoints.swift
+++ b/Sources/Services/AWSSageMakerRuntime/Sources/AWSSageMakerRuntime/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSageMakerRuntime/Tests/AWSSageMakerRuntimeTests/EndpointResolverTest.swift b/Sources/Services/AWSSageMakerRuntime/Tests/AWSSageMakerRuntimeTests/EndpointResolverTest.swift
index 14cf68ef219..0f194b624ef 100644
--- a/Sources/Services/AWSSageMakerRuntime/Tests/AWSSageMakerRuntimeTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSageMakerRuntime/Tests/AWSSageMakerRuntimeTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSageMakerRuntime
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -830,7 +831,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -927,7 +928,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSagemakerEdge/Sources/AWSSagemakerEdge/Endpoints.swift b/Sources/Services/AWSSagemakerEdge/Sources/AWSSagemakerEdge/Endpoints.swift
index 58eac994aa0..5efa6c1d59f 100644
--- a/Sources/Services/AWSSagemakerEdge/Sources/AWSSagemakerEdge/Endpoints.swift
+++ b/Sources/Services/AWSSagemakerEdge/Sources/AWSSagemakerEdge/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSagemakerEdge/Tests/AWSSagemakerEdgeTests/EndpointResolverTest.swift b/Sources/Services/AWSSagemakerEdge/Tests/AWSSagemakerEdgeTests/EndpointResolverTest.swift
index 6f34d215599..8939c044524 100644
--- a/Sources/Services/AWSSagemakerEdge/Tests/AWSSagemakerEdgeTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSagemakerEdge/Tests/AWSSagemakerEdgeTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSagemakerEdge
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -390,7 +391,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -429,7 +430,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -507,7 +508,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -528,7 +529,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSavingsplans/Sources/AWSSavingsplans/Endpoints.swift b/Sources/Services/AWSSavingsplans/Sources/AWSSavingsplans/Endpoints.swift
index 6a38c012afe..5bd4ffa4420 100644
--- a/Sources/Services/AWSSavingsplans/Sources/AWSSavingsplans/Endpoints.swift
+++ b/Sources/Services/AWSSavingsplans/Sources/AWSSavingsplans/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSavingsplans/Tests/AWSSavingsplansTests/EndpointResolverTest.swift b/Sources/Services/AWSSavingsplans/Tests/AWSSavingsplansTests/EndpointResolverTest.swift
index 456d7220b4e..5de5cbe141d 100644
--- a/Sources/Services/AWSSavingsplans/Tests/AWSSavingsplansTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSavingsplans/Tests/AWSSavingsplansTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSavingsplans
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,15 +32,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "savingsplans",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -59,7 +60,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -79,7 +80,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -99,7 +100,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -119,15 +120,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "savingsplans",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -147,7 +148,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -167,7 +168,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -187,7 +188,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -207,7 +208,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -227,7 +228,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -247,7 +248,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -267,7 +268,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -287,7 +288,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -326,7 +327,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -365,7 +366,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -404,7 +405,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -443,7 +444,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -464,7 +465,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -484,7 +485,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSScheduler/Sources/AWSScheduler/Endpoints.swift b/Sources/Services/AWSScheduler/Sources/AWSScheduler/Endpoints.swift
index 059df69963b..fe192225e69 100644
--- a/Sources/Services/AWSScheduler/Sources/AWSScheduler/Endpoints.swift
+++ b/Sources/Services/AWSScheduler/Sources/AWSScheduler/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSScheduler/Tests/AWSSchedulerTests/EndpointResolverTest.swift b/Sources/Services/AWSScheduler/Tests/AWSSchedulerTests/EndpointResolverTest.swift
index d143919fb47..17bce9d381c 100644
--- a/Sources/Services/AWSScheduler/Tests/AWSSchedulerTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSScheduler/Tests/AWSSchedulerTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSScheduler
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSchemas/Sources/AWSSchemas/Endpoints.swift b/Sources/Services/AWSSchemas/Sources/AWSSchemas/Endpoints.swift
index 31362f05d4b..48a3ac12ee7 100644
--- a/Sources/Services/AWSSchemas/Sources/AWSSchemas/Endpoints.swift
+++ b/Sources/Services/AWSSchemas/Sources/AWSSchemas/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSchemas/Tests/AWSSchemasTests/EndpointResolverTest.swift b/Sources/Services/AWSSchemas/Tests/AWSSchemasTests/EndpointResolverTest.swift
index 47e102fb16f..46bb6470234 100644
--- a/Sources/Services/AWSSchemas/Tests/AWSSchemasTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSchemas/Tests/AWSSchemasTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSchemas
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -610,7 +611,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -649,7 +650,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -688,7 +689,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -727,7 +728,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -768,7 +769,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSecretsManager/Sources/AWSSecretsManager/Endpoints.swift b/Sources/Services/AWSSecretsManager/Sources/AWSSecretsManager/Endpoints.swift
index 8133093a4ee..a8c5d0e4aa4 100644
--- a/Sources/Services/AWSSecretsManager/Sources/AWSSecretsManager/Endpoints.swift
+++ b/Sources/Services/AWSSecretsManager/Sources/AWSSecretsManager/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSecretsManager/Tests/AWSSecretsManagerTests/EndpointResolverTest.swift b/Sources/Services/AWSSecretsManager/Tests/AWSSecretsManagerTests/EndpointResolverTest.swift
index b0a2313e16b..7462157b611 100644
--- a/Sources/Services/AWSSecretsManager/Tests/AWSSecretsManagerTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSecretsManager/Tests/AWSSecretsManagerTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSecretsManager
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -870,7 +871,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -967,7 +968,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSecurityHub/Sources/AWSSecurityHub/Endpoints.swift b/Sources/Services/AWSSecurityHub/Sources/AWSSecurityHub/Endpoints.swift
index ae71e16047e..0160e59c730 100644
--- a/Sources/Services/AWSSecurityHub/Sources/AWSSecurityHub/Endpoints.swift
+++ b/Sources/Services/AWSSecurityHub/Sources/AWSSecurityHub/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSecurityHub/Tests/AWSSecurityHubTests/EndpointResolverTest.swift b/Sources/Services/AWSSecurityHub/Tests/AWSSecurityHubTests/EndpointResolverTest.swift
index 822dbed5f66..a0d61163b8f 100644
--- a/Sources/Services/AWSSecurityHub/Tests/AWSSecurityHubTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSecurityHub/Tests/AWSSecurityHubTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSecurityHub
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -830,7 +831,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -869,7 +870,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -947,7 +948,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSecurityIR/Sources/AWSSecurityIR/Endpoints.swift b/Sources/Services/AWSSecurityIR/Sources/AWSSecurityIR/Endpoints.swift
index 1432db4d4f1..55fd0c12c00 100644
--- a/Sources/Services/AWSSecurityIR/Sources/AWSSecurityIR/Endpoints.swift
+++ b/Sources/Services/AWSSecurityIR/Sources/AWSSecurityIR/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSecurityIR/Tests/AWSSecurityIRTests/EndpointResolverTest.swift b/Sources/Services/AWSSecurityIR/Tests/AWSSecurityIRTests/EndpointResolverTest.swift
index 5ac1df14276..0b88af03558 100644
--- a/Sources/Services/AWSSecurityIR/Tests/AWSSecurityIRTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSecurityIR/Tests/AWSSecurityIRTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSecurityIR
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -67,7 +68,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -86,7 +87,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -105,7 +106,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -124,7 +125,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -143,7 +144,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -162,7 +163,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -181,7 +182,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -200,7 +201,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -219,7 +220,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -238,7 +239,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -257,7 +258,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -276,7 +277,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -295,7 +296,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -314,7 +315,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSecurityLake/Sources/AWSSecurityLake/Endpoints.swift b/Sources/Services/AWSSecurityLake/Sources/AWSSecurityLake/Endpoints.swift
index 3f51c2661a0..5ee186a6bbe 100644
--- a/Sources/Services/AWSSecurityLake/Sources/AWSSecurityLake/Endpoints.swift
+++ b/Sources/Services/AWSSecurityLake/Sources/AWSSecurityLake/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSecurityLake/Tests/AWSSecurityLakeTests/EndpointResolverTest.swift b/Sources/Services/AWSSecurityLake/Tests/AWSSecurityLakeTests/EndpointResolverTest.swift
index 4f47ffe99a1..b2deb4648ae 100644
--- a/Sources/Services/AWSSecurityLake/Tests/AWSSecurityLakeTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSecurityLake/Tests/AWSSecurityLakeTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSecurityLake
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSServerlessApplicationRepository/Sources/AWSServerlessApplicationRepository/Endpoints.swift b/Sources/Services/AWSServerlessApplicationRepository/Sources/AWSServerlessApplicationRepository/Endpoints.swift
index f371440c029..8fb9f333f9f 100644
--- a/Sources/Services/AWSServerlessApplicationRepository/Sources/AWSServerlessApplicationRepository/Endpoints.swift
+++ b/Sources/Services/AWSServerlessApplicationRepository/Sources/AWSServerlessApplicationRepository/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSServerlessApplicationRepository/Tests/AWSServerlessApplicationRepositoryTests/EndpointResolverTest.swift b/Sources/Services/AWSServerlessApplicationRepository/Tests/AWSServerlessApplicationRepositoryTests/EndpointResolverTest.swift
index 365d0e00872..9c045bd9735 100644
--- a/Sources/Services/AWSServerlessApplicationRepository/Tests/AWSServerlessApplicationRepositoryTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSServerlessApplicationRepository/Tests/AWSServerlessApplicationRepositoryTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSServerlessApplicationRepository
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -690,7 +691,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -729,7 +730,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -768,7 +769,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -807,7 +808,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -828,7 +829,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -848,7 +849,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSServiceCatalog/Sources/AWSServiceCatalog/Endpoints.swift b/Sources/Services/AWSServiceCatalog/Sources/AWSServiceCatalog/Endpoints.swift
index 5e3bdc73857..938be179200 100644
--- a/Sources/Services/AWSServiceCatalog/Sources/AWSServiceCatalog/Endpoints.swift
+++ b/Sources/Services/AWSServiceCatalog/Sources/AWSServiceCatalog/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSServiceCatalog/Tests/AWSServiceCatalogTests/EndpointResolverTest.swift b/Sources/Services/AWSServiceCatalog/Tests/AWSServiceCatalogTests/EndpointResolverTest.swift
index 6cc0d1b9a68..4719eeac972 100644
--- a/Sources/Services/AWSServiceCatalog/Tests/AWSServiceCatalogTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSServiceCatalog/Tests/AWSServiceCatalogTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSServiceCatalog
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -830,7 +831,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -869,7 +870,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -947,7 +948,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSServiceCatalogAppRegistry/Sources/AWSServiceCatalogAppRegistry/Endpoints.swift b/Sources/Services/AWSServiceCatalogAppRegistry/Sources/AWSServiceCatalogAppRegistry/Endpoints.swift
index 1ad060e5667..f82d625ba90 100644
--- a/Sources/Services/AWSServiceCatalogAppRegistry/Sources/AWSServiceCatalogAppRegistry/Endpoints.swift
+++ b/Sources/Services/AWSServiceCatalogAppRegistry/Sources/AWSServiceCatalogAppRegistry/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSServiceCatalogAppRegistry/Tests/AWSServiceCatalogAppRegistryTests/EndpointResolverTest.swift b/Sources/Services/AWSServiceCatalogAppRegistry/Tests/AWSServiceCatalogAppRegistryTests/EndpointResolverTest.swift
index 49357e100d4..168de2c6d9d 100644
--- a/Sources/Services/AWSServiceCatalogAppRegistry/Tests/AWSServiceCatalogAppRegistryTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSServiceCatalogAppRegistry/Tests/AWSServiceCatalogAppRegistryTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSServiceCatalogAppRegistry
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -810,7 +811,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -849,7 +850,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -927,7 +928,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSServiceDiscovery/Sources/AWSServiceDiscovery/Endpoints.swift b/Sources/Services/AWSServiceDiscovery/Sources/AWSServiceDiscovery/Endpoints.swift
index e99c31e9032..370e896ffc7 100644
--- a/Sources/Services/AWSServiceDiscovery/Sources/AWSServiceDiscovery/Endpoints.swift
+++ b/Sources/Services/AWSServiceDiscovery/Sources/AWSServiceDiscovery/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSServiceDiscovery/Tests/AWSServiceDiscoveryTests/EndpointResolverTest.swift b/Sources/Services/AWSServiceDiscovery/Tests/AWSServiceDiscoveryTests/EndpointResolverTest.swift
index 719a4a5129d..4cc6bdee55c 100644
--- a/Sources/Services/AWSServiceDiscovery/Tests/AWSServiceDiscoveryTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSServiceDiscovery/Tests/AWSServiceDiscoveryTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSServiceDiscovery
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -810,7 +811,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -849,7 +850,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -927,7 +928,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSServiceQuotas/Sources/AWSServiceQuotas/Endpoints.swift b/Sources/Services/AWSServiceQuotas/Sources/AWSServiceQuotas/Endpoints.swift
index a8772a8006a..7e58daa07dd 100644
--- a/Sources/Services/AWSServiceQuotas/Sources/AWSServiceQuotas/Endpoints.swift
+++ b/Sources/Services/AWSServiceQuotas/Sources/AWSServiceQuotas/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSServiceQuotas/Tests/AWSServiceQuotasTests/EndpointResolverTest.swift b/Sources/Services/AWSServiceQuotas/Tests/AWSServiceQuotasTests/EndpointResolverTest.swift
index c6e64e67f9d..3f4c708d3a4 100644
--- a/Sources/Services/AWSServiceQuotas/Tests/AWSServiceQuotasTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSServiceQuotas/Tests/AWSServiceQuotasTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSServiceQuotas
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -750,7 +751,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -789,7 +790,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -828,7 +829,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -867,7 +868,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -888,7 +889,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSShield/Sources/AWSShield/Endpoints.swift b/Sources/Services/AWSShield/Sources/AWSShield/Endpoints.swift
index 221e3450ac2..cffd1b399a4 100644
--- a/Sources/Services/AWSShield/Sources/AWSShield/Endpoints.swift
+++ b/Sources/Services/AWSShield/Sources/AWSShield/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSShield/Tests/AWSShieldTests/EndpointResolverTest.swift b/Sources/Services/AWSShield/Tests/AWSShieldTests/EndpointResolverTest.swift
index d5eed545d25..15a5efe68b5 100644
--- a/Sources/Services/AWSShield/Tests/AWSShieldTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSShield/Tests/AWSShieldTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSShield
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,15 +32,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "shield",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -59,15 +60,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "shield",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,7 +88,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -107,15 +108,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "shield",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -135,7 +136,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -155,15 +156,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "shield",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -183,7 +184,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -203,7 +204,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -223,7 +224,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -243,7 +244,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -263,7 +264,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -283,7 +284,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -303,7 +304,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -323,7 +324,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -362,7 +363,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -401,7 +402,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -440,7 +441,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -479,7 +480,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -500,7 +501,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -520,7 +521,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSigner/Sources/AWSSigner/Endpoints.swift b/Sources/Services/AWSSigner/Sources/AWSSigner/Endpoints.swift
index 1e61e669315..33558938bc8 100644
--- a/Sources/Services/AWSSigner/Sources/AWSSigner/Endpoints.swift
+++ b/Sources/Services/AWSSigner/Sources/AWSSigner/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSigner/Tests/AWSSignerTests/EndpointResolverTest.swift b/Sources/Services/AWSSigner/Tests/AWSSignerTests/EndpointResolverTest.swift
index f22f948a070..8b251cd15a9 100644
--- a/Sources/Services/AWSSigner/Tests/AWSSignerTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSigner/Tests/AWSSignerTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSigner
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSimSpaceWeaver/Sources/AWSSimSpaceWeaver/Endpoints.swift b/Sources/Services/AWSSimSpaceWeaver/Sources/AWSSimSpaceWeaver/Endpoints.swift
index cca2c41739b..c42e796c4a6 100644
--- a/Sources/Services/AWSSimSpaceWeaver/Sources/AWSSimSpaceWeaver/Endpoints.swift
+++ b/Sources/Services/AWSSimSpaceWeaver/Sources/AWSSimSpaceWeaver/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSimSpaceWeaver/Tests/AWSSimSpaceWeaverTests/EndpointResolverTest.swift b/Sources/Services/AWSSimSpaceWeaver/Tests/AWSSimSpaceWeaverTests/EndpointResolverTest.swift
index 421917f1ea7..fb995fa6f20 100644
--- a/Sources/Services/AWSSimSpaceWeaver/Tests/AWSSimSpaceWeaverTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSimSpaceWeaver/Tests/AWSSimSpaceWeaverTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSimSpaceWeaver
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSnowDeviceManagement/Sources/AWSSnowDeviceManagement/Endpoints.swift b/Sources/Services/AWSSnowDeviceManagement/Sources/AWSSnowDeviceManagement/Endpoints.swift
index bbdce08e782..d3cb66e7009 100644
--- a/Sources/Services/AWSSnowDeviceManagement/Sources/AWSSnowDeviceManagement/Endpoints.swift
+++ b/Sources/Services/AWSSnowDeviceManagement/Sources/AWSSnowDeviceManagement/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSnowDeviceManagement/Tests/AWSSnowDeviceManagementTests/EndpointResolverTest.swift b/Sources/Services/AWSSnowDeviceManagement/Tests/AWSSnowDeviceManagementTests/EndpointResolverTest.swift
index fc69ed4a740..40063408a71 100644
--- a/Sources/Services/AWSSnowDeviceManagement/Tests/AWSSnowDeviceManagementTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSnowDeviceManagement/Tests/AWSSnowDeviceManagementTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSnowDeviceManagement
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSnowball/Sources/AWSSnowball/Endpoints.swift b/Sources/Services/AWSSnowball/Sources/AWSSnowball/Endpoints.swift
index 36ada2dfd85..2ead479a914 100644
--- a/Sources/Services/AWSSnowball/Sources/AWSSnowball/Endpoints.swift
+++ b/Sources/Services/AWSSnowball/Sources/AWSSnowball/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSnowball/Tests/AWSSnowballTests/EndpointResolverTest.swift b/Sources/Services/AWSSnowball/Tests/AWSSnowballTests/EndpointResolverTest.swift
index 1d960c19f1b..5d9cc6c049f 100644
--- a/Sources/Services/AWSSnowball/Tests/AWSSnowballTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSnowball/Tests/AWSSnowballTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSnowball
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -851,7 +852,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -871,7 +872,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -891,7 +892,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -911,7 +912,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -931,7 +932,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -951,7 +952,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -971,7 +972,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -991,7 +992,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1011,7 +1012,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1031,7 +1032,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1070,7 +1071,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1109,7 +1110,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1148,7 +1149,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1188,7 +1189,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1208,7 +1209,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSocialMessaging/Sources/AWSSocialMessaging/Endpoints.swift b/Sources/Services/AWSSocialMessaging/Sources/AWSSocialMessaging/Endpoints.swift
index cb43ef1f34f..762a4509258 100644
--- a/Sources/Services/AWSSocialMessaging/Sources/AWSSocialMessaging/Endpoints.swift
+++ b/Sources/Services/AWSSocialMessaging/Sources/AWSSocialMessaging/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSocialMessaging/Tests/AWSSocialMessagingTests/EndpointResolverTest.swift b/Sources/Services/AWSSocialMessaging/Tests/AWSSocialMessagingTests/EndpointResolverTest.swift
index e2ae9e47987..a146bb81b98 100644
--- a/Sources/Services/AWSSocialMessaging/Tests/AWSSocialMessagingTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSocialMessaging/Tests/AWSSocialMessagingTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSocialMessaging
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSsmSap/Sources/AWSSsmSap/Endpoints.swift b/Sources/Services/AWSSsmSap/Sources/AWSSsmSap/Endpoints.swift
index 8be6e0e628b..6dcee2ce44c 100644
--- a/Sources/Services/AWSSsmSap/Sources/AWSSsmSap/Endpoints.swift
+++ b/Sources/Services/AWSSsmSap/Sources/AWSSsmSap/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSsmSap/Tests/AWSSsmSapTests/EndpointResolverTest.swift b/Sources/Services/AWSSsmSap/Tests/AWSSsmSapTests/EndpointResolverTest.swift
index 2205f188c76..d2e85979bc6 100644
--- a/Sources/Services/AWSSsmSap/Tests/AWSSsmSapTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSsmSap/Tests/AWSSsmSapTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSsmSap
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSStorageGateway/Sources/AWSStorageGateway/Endpoints.swift b/Sources/Services/AWSStorageGateway/Sources/AWSStorageGateway/Endpoints.swift
index 1199e336741..8036cc8b808 100644
--- a/Sources/Services/AWSStorageGateway/Sources/AWSStorageGateway/Endpoints.swift
+++ b/Sources/Services/AWSStorageGateway/Sources/AWSStorageGateway/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSStorageGateway/Tests/AWSStorageGatewayTests/EndpointResolverTest.swift b/Sources/Services/AWSStorageGateway/Tests/AWSStorageGatewayTests/EndpointResolverTest.swift
index 49ce2ea74d9..c2f4c8bb9d6 100644
--- a/Sources/Services/AWSStorageGateway/Tests/AWSStorageGatewayTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSStorageGateway/Tests/AWSStorageGatewayTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSStorageGateway
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -850,7 +851,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -889,7 +890,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -967,7 +968,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1008,7 +1009,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSupplyChain/Sources/AWSSupplyChain/Endpoints.swift b/Sources/Services/AWSSupplyChain/Sources/AWSSupplyChain/Endpoints.swift
index 77d00f2ef1f..b50389b83bc 100644
--- a/Sources/Services/AWSSupplyChain/Sources/AWSSupplyChain/Endpoints.swift
+++ b/Sources/Services/AWSSupplyChain/Sources/AWSSupplyChain/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSupplyChain/Tests/AWSSupplyChainTests/EndpointResolverTest.swift b/Sources/Services/AWSSupplyChain/Tests/AWSSupplyChainTests/EndpointResolverTest.swift
index 7da23675db4..005b32ef31e 100644
--- a/Sources/Services/AWSSupplyChain/Tests/AWSSupplyChainTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSupplyChain/Tests/AWSSupplyChainTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSupplyChain
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSupport/Sources/AWSSupport/Endpoints.swift b/Sources/Services/AWSSupport/Sources/AWSSupport/Endpoints.swift
index 819955d1f3c..c27f71e8014 100644
--- a/Sources/Services/AWSSupport/Sources/AWSSupport/Endpoints.swift
+++ b/Sources/Services/AWSSupport/Sources/AWSSupport/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSupport/Tests/AWSSupportTests/EndpointResolverTest.swift b/Sources/Services/AWSSupport/Tests/AWSSupportTests/EndpointResolverTest.swift
index f0b17eef42d..45971e3635f 100644
--- a/Sources/Services/AWSSupport/Tests/AWSSupportTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSupport/Tests/AWSSupportTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSupport
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,15 +32,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "support",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -59,7 +60,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -79,7 +80,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -99,7 +100,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -119,15 +120,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "support",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -147,15 +148,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "support",
                         "signingRegion": "cn-north-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -175,7 +176,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -195,7 +196,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -215,7 +216,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -235,15 +236,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "support",
                         "signingRegion": "cn-north-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -263,15 +264,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "support",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,15 +292,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "support",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -319,7 +320,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -339,15 +340,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "support",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -367,7 +368,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -387,15 +388,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "support",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -415,15 +416,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "support",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -462,7 +463,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -501,15 +502,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "support",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -529,15 +530,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "support",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -576,7 +577,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -615,15 +616,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "support",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -644,7 +645,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -664,7 +665,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSupportApp/Sources/AWSSupportApp/Endpoints.swift b/Sources/Services/AWSSupportApp/Sources/AWSSupportApp/Endpoints.swift
index 32beaabcbda..ac71057ed31 100644
--- a/Sources/Services/AWSSupportApp/Sources/AWSSupportApp/Endpoints.swift
+++ b/Sources/Services/AWSSupportApp/Sources/AWSSupportApp/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSupportApp/Tests/AWSSupportAppTests/EndpointResolverTest.swift b/Sources/Services/AWSSupportApp/Tests/AWSSupportAppTests/EndpointResolverTest.swift
index ebc1420f69a..55ce7b48942 100644
--- a/Sources/Services/AWSSupportApp/Tests/AWSSupportAppTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSupportApp/Tests/AWSSupportAppTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSupportApp
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSSynthetics/Sources/AWSSynthetics/Endpoints.swift b/Sources/Services/AWSSynthetics/Sources/AWSSynthetics/Endpoints.swift
index 09da84c2bb1..d8998fece9d 100644
--- a/Sources/Services/AWSSynthetics/Sources/AWSSynthetics/Endpoints.swift
+++ b/Sources/Services/AWSSynthetics/Sources/AWSSynthetics/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSSynthetics/Tests/AWSSyntheticsTests/EndpointResolverTest.swift b/Sources/Services/AWSSynthetics/Tests/AWSSyntheticsTests/EndpointResolverTest.swift
index 9d0b23c88bd..06d254cee6d 100644
--- a/Sources/Services/AWSSynthetics/Tests/AWSSyntheticsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSSynthetics/Tests/AWSSyntheticsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSSynthetics
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -850,7 +851,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -889,7 +890,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSTaxSettings/Sources/AWSTaxSettings/Endpoints.swift b/Sources/Services/AWSTaxSettings/Sources/AWSTaxSettings/Endpoints.swift
index 0ffde8c93f4..8c301c966db 100644
--- a/Sources/Services/AWSTaxSettings/Sources/AWSTaxSettings/Endpoints.swift
+++ b/Sources/Services/AWSTaxSettings/Sources/AWSTaxSettings/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSTaxSettings/Tests/AWSTaxSettingsTests/EndpointResolverTest.swift b/Sources/Services/AWSTaxSettings/Tests/AWSTaxSettingsTests/EndpointResolverTest.swift
index da85008fb96..63480c88caf 100644
--- a/Sources/Services/AWSTaxSettings/Tests/AWSTaxSettingsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSTaxSettings/Tests/AWSTaxSettingsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSTaxSettings
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -30,7 +31,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,14 +88,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -114,14 +115,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -141,14 +142,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -168,14 +169,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -195,14 +196,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -222,14 +223,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -249,14 +250,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -276,14 +277,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "cn-northwest-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -303,14 +304,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -330,14 +331,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -357,14 +358,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -384,14 +385,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-gov-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -430,14 +431,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -476,14 +477,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-iso-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -522,14 +523,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,14 +569,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isob-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -614,14 +615,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -660,14 +661,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "eu-isoe-west-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -706,14 +707,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -752,14 +753,14 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingRegion": "us-isof-south-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSTextract/Sources/AWSTextract/Endpoints.swift b/Sources/Services/AWSTextract/Sources/AWSTextract/Endpoints.swift
index 73b59158f3d..b810c340127 100644
--- a/Sources/Services/AWSTextract/Sources/AWSTextract/Endpoints.swift
+++ b/Sources/Services/AWSTextract/Sources/AWSTextract/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSTextract/Tests/AWSTextractTests/EndpointResolverTest.swift b/Sources/Services/AWSTextract/Tests/AWSTextractTests/EndpointResolverTest.swift
index 5639bce80df..f918833e5f0 100644
--- a/Sources/Services/AWSTextract/Tests/AWSTextractTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSTextract/Tests/AWSTextractTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSTextract
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -650,7 +651,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -689,7 +690,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -767,7 +768,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -788,7 +789,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -808,7 +809,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSTimestreamInfluxDB/Sources/AWSTimestreamInfluxDB/Endpoints.swift b/Sources/Services/AWSTimestreamInfluxDB/Sources/AWSTimestreamInfluxDB/Endpoints.swift
index 817a6e99b6c..089acacf65a 100644
--- a/Sources/Services/AWSTimestreamInfluxDB/Sources/AWSTimestreamInfluxDB/Endpoints.swift
+++ b/Sources/Services/AWSTimestreamInfluxDB/Sources/AWSTimestreamInfluxDB/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSTimestreamInfluxDB/Tests/AWSTimestreamInfluxDBTests/EndpointResolverTest.swift b/Sources/Services/AWSTimestreamInfluxDB/Tests/AWSTimestreamInfluxDBTests/EndpointResolverTest.swift
index ae46d2dca06..b35ae5297d3 100644
--- a/Sources/Services/AWSTimestreamInfluxDB/Tests/AWSTimestreamInfluxDBTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSTimestreamInfluxDB/Tests/AWSTimestreamInfluxDBTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSTimestreamInfluxDB
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSTimestreamQuery/Sources/AWSTimestreamQuery/Endpoints.swift b/Sources/Services/AWSTimestreamQuery/Sources/AWSTimestreamQuery/Endpoints.swift
index a5d99efd7d0..261d7b9f93c 100644
--- a/Sources/Services/AWSTimestreamQuery/Sources/AWSTimestreamQuery/Endpoints.swift
+++ b/Sources/Services/AWSTimestreamQuery/Sources/AWSTimestreamQuery/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSTimestreamQuery/Tests/AWSTimestreamQueryTests/EndpointResolverTest.swift b/Sources/Services/AWSTimestreamQuery/Tests/AWSTimestreamQueryTests/EndpointResolverTest.swift
index 88d4030a61f..0b05b24be41 100644
--- a/Sources/Services/AWSTimestreamQuery/Tests/AWSTimestreamQueryTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSTimestreamQuery/Tests/AWSTimestreamQueryTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSTimestreamQuery
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSTimestreamWrite/Sources/AWSTimestreamWrite/Endpoints.swift b/Sources/Services/AWSTimestreamWrite/Sources/AWSTimestreamWrite/Endpoints.swift
index f80dd5348e9..ab3ecba6303 100644
--- a/Sources/Services/AWSTimestreamWrite/Sources/AWSTimestreamWrite/Endpoints.swift
+++ b/Sources/Services/AWSTimestreamWrite/Sources/AWSTimestreamWrite/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSTimestreamWrite/Tests/AWSTimestreamWriteTests/EndpointResolverTest.swift b/Sources/Services/AWSTimestreamWrite/Tests/AWSTimestreamWriteTests/EndpointResolverTest.swift
index f1bb29d96b5..b36fbf3f042 100644
--- a/Sources/Services/AWSTimestreamWrite/Tests/AWSTimestreamWriteTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSTimestreamWrite/Tests/AWSTimestreamWriteTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSTimestreamWrite
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -330,7 +331,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -369,7 +370,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -408,7 +409,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -447,7 +448,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSTnb/Sources/AWSTnb/Endpoints.swift b/Sources/Services/AWSTnb/Sources/AWSTnb/Endpoints.swift
index 1098715c305..c85d421e544 100644
--- a/Sources/Services/AWSTnb/Sources/AWSTnb/Endpoints.swift
+++ b/Sources/Services/AWSTnb/Sources/AWSTnb/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSTnb/Tests/AWSTnbTests/EndpointResolverTest.swift b/Sources/Services/AWSTnb/Tests/AWSTnbTests/EndpointResolverTest.swift
index 3f3b6f29434..11abbaf9a04 100644
--- a/Sources/Services/AWSTnb/Tests/AWSTnbTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSTnb/Tests/AWSTnbTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSTnb
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSTranscribe/Sources/AWSTranscribe/Endpoints.swift b/Sources/Services/AWSTranscribe/Sources/AWSTranscribe/Endpoints.swift
index 6767108af2b..e0b9ef163d0 100644
--- a/Sources/Services/AWSTranscribe/Sources/AWSTranscribe/Endpoints.swift
+++ b/Sources/Services/AWSTranscribe/Sources/AWSTranscribe/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSTranscribe/Tests/AWSTranscribeTests/EndpointResolverTest.swift b/Sources/Services/AWSTranscribe/Tests/AWSTranscribeTests/EndpointResolverTest.swift
index 78f5f2ca433..acf98b7e6e0 100644
--- a/Sources/Services/AWSTranscribe/Tests/AWSTranscribeTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSTranscribe/Tests/AWSTranscribeTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSTranscribe
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -810,7 +811,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -868,7 +869,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -907,7 +908,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -928,7 +929,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -948,7 +949,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSTranscribeStreaming/Sources/AWSTranscribeStreaming/Endpoints.swift b/Sources/Services/AWSTranscribeStreaming/Sources/AWSTranscribeStreaming/Endpoints.swift
index b46a3888561..eee8f78d649 100644
--- a/Sources/Services/AWSTranscribeStreaming/Sources/AWSTranscribeStreaming/Endpoints.swift
+++ b/Sources/Services/AWSTranscribeStreaming/Sources/AWSTranscribeStreaming/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSTranscribeStreaming/Tests/AWSTranscribeStreamingTests/EndpointResolverTest.swift b/Sources/Services/AWSTranscribeStreaming/Tests/AWSTranscribeStreamingTests/EndpointResolverTest.swift
index 86bfcd7f1ba..2cc77a553e5 100644
--- a/Sources/Services/AWSTranscribeStreaming/Tests/AWSTranscribeStreamingTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSTranscribeStreaming/Tests/AWSTranscribeStreamingTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSTranscribeStreaming
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -550,7 +551,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -608,7 +609,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -647,7 +648,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -668,7 +669,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -688,7 +689,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSTransfer/Sources/AWSTransfer/Endpoints.swift b/Sources/Services/AWSTransfer/Sources/AWSTransfer/Endpoints.swift
index ec850aa4c48..1726bacffb3 100644
--- a/Sources/Services/AWSTransfer/Sources/AWSTransfer/Endpoints.swift
+++ b/Sources/Services/AWSTransfer/Sources/AWSTransfer/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSTransfer/Tests/AWSTransferTests/EndpointResolverTest.swift b/Sources/Services/AWSTransfer/Tests/AWSTransferTests/EndpointResolverTest.swift
index 08fdeac3e4e..c438125c655 100644
--- a/Sources/Services/AWSTransfer/Tests/AWSTransferTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSTransfer/Tests/AWSTransferTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSTransfer
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -830,7 +831,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -869,7 +870,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -947,7 +948,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSTranslate/Sources/AWSTranslate/Endpoints.swift b/Sources/Services/AWSTranslate/Sources/AWSTranslate/Endpoints.swift
index 28b5a355d47..7d39487f6a7 100644
--- a/Sources/Services/AWSTranslate/Sources/AWSTranslate/Endpoints.swift
+++ b/Sources/Services/AWSTranslate/Sources/AWSTranslate/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSTranslate/Tests/AWSTranslateTests/EndpointResolverTest.swift b/Sources/Services/AWSTranslate/Tests/AWSTranslateTests/EndpointResolverTest.swift
index 3cd5bef4add..1a42d2d10e1 100644
--- a/Sources/Services/AWSTranslate/Tests/AWSTranslateTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSTranslate/Tests/AWSTranslateTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSTranslate
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -690,7 +691,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -787,7 +788,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -808,7 +809,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -828,7 +829,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSTrustedAdvisor/Sources/AWSTrustedAdvisor/Endpoints.swift b/Sources/Services/AWSTrustedAdvisor/Sources/AWSTrustedAdvisor/Endpoints.swift
index 99ab220d1f2..4f0e7089ed4 100644
--- a/Sources/Services/AWSTrustedAdvisor/Sources/AWSTrustedAdvisor/Endpoints.swift
+++ b/Sources/Services/AWSTrustedAdvisor/Sources/AWSTrustedAdvisor/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSTrustedAdvisor/Tests/AWSTrustedAdvisorTests/EndpointResolverTest.swift b/Sources/Services/AWSTrustedAdvisor/Tests/AWSTrustedAdvisorTests/EndpointResolverTest.swift
index 2b2c13bade5..8b481754521 100644
--- a/Sources/Services/AWSTrustedAdvisor/Tests/AWSTrustedAdvisorTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSTrustedAdvisor/Tests/AWSTrustedAdvisorTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSTrustedAdvisor
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSVPCLattice/Sources/AWSVPCLattice/Endpoints.swift b/Sources/Services/AWSVPCLattice/Sources/AWSVPCLattice/Endpoints.swift
index f5f4973c4ec..8c331aa20a3 100644
--- a/Sources/Services/AWSVPCLattice/Sources/AWSVPCLattice/Endpoints.swift
+++ b/Sources/Services/AWSVPCLattice/Sources/AWSVPCLattice/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSVPCLattice/Tests/AWSVPCLatticeTests/EndpointResolverTest.swift b/Sources/Services/AWSVPCLattice/Tests/AWSVPCLatticeTests/EndpointResolverTest.swift
index 2001a8ae45e..9c1236e7152 100644
--- a/Sources/Services/AWSVPCLattice/Tests/AWSVPCLatticeTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSVPCLattice/Tests/AWSVPCLatticeTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSVPCLattice
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSVerifiedPermissions/Sources/AWSVerifiedPermissions/Endpoints.swift b/Sources/Services/AWSVerifiedPermissions/Sources/AWSVerifiedPermissions/Endpoints.swift
index 6cb5e913909..130cc36dbf6 100644
--- a/Sources/Services/AWSVerifiedPermissions/Sources/AWSVerifiedPermissions/Endpoints.swift
+++ b/Sources/Services/AWSVerifiedPermissions/Sources/AWSVerifiedPermissions/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSVerifiedPermissions/Tests/AWSVerifiedPermissionsTests/EndpointResolverTest.swift b/Sources/Services/AWSVerifiedPermissions/Tests/AWSVerifiedPermissionsTests/EndpointResolverTest.swift
index 80ffe313d8f..29f9db05e69 100644
--- a/Sources/Services/AWSVerifiedPermissions/Tests/AWSVerifiedPermissionsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSVerifiedPermissions/Tests/AWSVerifiedPermissionsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSVerifiedPermissions
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSVoiceID/Sources/AWSVoiceID/Endpoints.swift b/Sources/Services/AWSVoiceID/Sources/AWSVoiceID/Endpoints.swift
index 7d31649ab46..43b5807c6cb 100644
--- a/Sources/Services/AWSVoiceID/Sources/AWSVoiceID/Endpoints.swift
+++ b/Sources/Services/AWSVoiceID/Sources/AWSVoiceID/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSVoiceID/Tests/AWSVoiceIDTests/EndpointResolverTest.swift b/Sources/Services/AWSVoiceID/Tests/AWSVoiceIDTests/EndpointResolverTest.swift
index 6771ecbfa4d..fd6d41de136 100644
--- a/Sources/Services/AWSVoiceID/Tests/AWSVoiceIDTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSVoiceID/Tests/AWSVoiceIDTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSVoiceID
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -410,7 +411,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -449,7 +450,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -527,7 +528,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSWAF/Sources/AWSWAF/Endpoints.swift b/Sources/Services/AWSWAF/Sources/AWSWAF/Endpoints.swift
index d9d7f3d665a..a20f81ca33c 100644
--- a/Sources/Services/AWSWAF/Sources/AWSWAF/Endpoints.swift
+++ b/Sources/Services/AWSWAF/Sources/AWSWAF/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSWAF/Tests/AWSWAFTests/EndpointResolverTest.swift b/Sources/Services/AWSWAF/Tests/AWSWAFTests/EndpointResolverTest.swift
index 223bdc079b4..921163f240f 100644
--- a/Sources/Services/AWSWAF/Tests/AWSWAFTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSWAF/Tests/AWSWAFTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSWAF
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,15 +32,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "waf",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -59,15 +60,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "waf",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -87,7 +88,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -107,15 +108,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "waf",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -135,7 +136,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -155,15 +156,15 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [
                 "authSchemes": [
                     [
                         "name": "sigv4",
                         "signingName": "waf",
                         "signingRegion": "us-east-1"
-                    ] as [String: AnyHashable]
-                ] as [AnyHashable]
+                    ]
+                ]
             ]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -183,7 +184,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -203,7 +204,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -223,7 +224,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -243,7 +244,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -263,7 +264,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -283,7 +284,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -303,7 +304,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -323,7 +324,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -362,7 +363,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -401,7 +402,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -440,7 +441,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -479,7 +480,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -500,7 +501,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -520,7 +521,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSWAFRegional/Sources/AWSWAFRegional/Endpoints.swift b/Sources/Services/AWSWAFRegional/Sources/AWSWAFRegional/Endpoints.swift
index 8971647da7f..ff5a585f9a2 100644
--- a/Sources/Services/AWSWAFRegional/Sources/AWSWAFRegional/Endpoints.swift
+++ b/Sources/Services/AWSWAFRegional/Sources/AWSWAFRegional/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSWAFRegional/Tests/AWSWAFRegionalTests/EndpointResolverTest.swift b/Sources/Services/AWSWAFRegional/Tests/AWSWAFRegionalTests/EndpointResolverTest.swift
index 6975c8b671d..1a8c6434fc2 100644
--- a/Sources/Services/AWSWAFRegional/Tests/AWSWAFRegionalTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSWAFRegional/Tests/AWSWAFRegionalTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSWAFRegional
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -851,7 +852,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -871,7 +872,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -891,7 +892,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -911,7 +912,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -931,7 +932,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -951,7 +952,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -971,7 +972,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -991,7 +992,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1011,7 +1012,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1031,7 +1032,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1051,7 +1052,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1071,7 +1072,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1091,7 +1092,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1111,7 +1112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1131,7 +1132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1151,7 +1152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1171,7 +1172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1210,7 +1211,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1249,7 +1250,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1288,7 +1289,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1327,7 +1328,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1348,7 +1349,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1368,7 +1369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSWAFV2/Sources/AWSWAFV2/Endpoints.swift b/Sources/Services/AWSWAFV2/Sources/AWSWAFV2/Endpoints.swift
index 6ebdbb6d073..ee28ff1b284 100644
--- a/Sources/Services/AWSWAFV2/Sources/AWSWAFV2/Endpoints.swift
+++ b/Sources/Services/AWSWAFV2/Sources/AWSWAFV2/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSWAFV2/Tests/AWSWAFV2Tests/EndpointResolverTest.swift b/Sources/Services/AWSWAFV2/Tests/AWSWAFV2Tests/EndpointResolverTest.swift
index d66da8b8d9d..68c056ce16d 100644
--- a/Sources/Services/AWSWAFV2/Tests/AWSWAFV2Tests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSWAFV2/Tests/AWSWAFV2Tests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSWAFV2
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -811,7 +812,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -831,7 +832,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -851,7 +852,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -871,7 +872,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -891,7 +892,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -911,7 +912,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -931,7 +932,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -951,7 +952,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -971,7 +972,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -991,7 +992,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1011,7 +1012,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1031,7 +1032,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1051,7 +1052,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1071,7 +1072,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1091,7 +1092,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1111,7 +1112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1131,7 +1132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1151,7 +1152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1171,7 +1172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1210,7 +1211,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1249,7 +1250,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1288,7 +1289,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1327,7 +1328,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1348,7 +1349,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -1368,7 +1369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSWellArchitected/Sources/AWSWellArchitected/Endpoints.swift b/Sources/Services/AWSWellArchitected/Sources/AWSWellArchitected/Endpoints.swift
index b021b9d9d8a..70bc0c05d52 100644
--- a/Sources/Services/AWSWellArchitected/Sources/AWSWellArchitected/Endpoints.swift
+++ b/Sources/Services/AWSWellArchitected/Sources/AWSWellArchitected/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSWellArchitected/Tests/AWSWellArchitectedTests/EndpointResolverTest.swift b/Sources/Services/AWSWellArchitected/Tests/AWSWellArchitectedTests/EndpointResolverTest.swift
index 89799a6583e..2eef5d39494 100644
--- a/Sources/Services/AWSWellArchitected/Tests/AWSWellArchitectedTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSWellArchitected/Tests/AWSWellArchitectedTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSWellArchitected
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -630,7 +631,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -669,7 +670,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -708,7 +709,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -747,7 +748,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -768,7 +769,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -788,7 +789,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSWisdom/Sources/AWSWisdom/Endpoints.swift b/Sources/Services/AWSWisdom/Sources/AWSWisdom/Endpoints.swift
index e12b09aae96..79f637635ab 100644
--- a/Sources/Services/AWSWisdom/Sources/AWSWisdom/Endpoints.swift
+++ b/Sources/Services/AWSWisdom/Sources/AWSWisdom/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSWisdom/Tests/AWSWisdomTests/EndpointResolverTest.swift b/Sources/Services/AWSWisdom/Tests/AWSWisdomTests/EndpointResolverTest.swift
index 8684f7296fe..68d6e775227 100644
--- a/Sources/Services/AWSWisdom/Tests/AWSWisdomTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSWisdom/Tests/AWSWisdomTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSWisdom
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -390,7 +391,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -429,7 +430,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -507,7 +508,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -528,7 +529,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSWorkDocs/Sources/AWSWorkDocs/Endpoints.swift b/Sources/Services/AWSWorkDocs/Sources/AWSWorkDocs/Endpoints.swift
index c6ef45b772a..830196f98d6 100644
--- a/Sources/Services/AWSWorkDocs/Sources/AWSWorkDocs/Endpoints.swift
+++ b/Sources/Services/AWSWorkDocs/Sources/AWSWorkDocs/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSWorkDocs/Tests/AWSWorkDocsTests/EndpointResolverTest.swift b/Sources/Services/AWSWorkDocs/Tests/AWSWorkDocsTests/EndpointResolverTest.swift
index 94b67a47948..123a18df523 100644
--- a/Sources/Services/AWSWorkDocs/Tests/AWSWorkDocsTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSWorkDocs/Tests/AWSWorkDocsTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSWorkDocs
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -410,7 +411,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -449,7 +450,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -527,7 +528,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -548,7 +549,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -568,7 +569,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSWorkMail/Sources/AWSWorkMail/Endpoints.swift b/Sources/Services/AWSWorkMail/Sources/AWSWorkMail/Endpoints.swift
index 80ec2ca6bce..14b1eae32a4 100644
--- a/Sources/Services/AWSWorkMail/Sources/AWSWorkMail/Endpoints.swift
+++ b/Sources/Services/AWSWorkMail/Sources/AWSWorkMail/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSWorkMail/Tests/AWSWorkMailTests/EndpointResolverTest.swift b/Sources/Services/AWSWorkMail/Tests/AWSWorkMailTests/EndpointResolverTest.swift
index 89ba46f2d3c..0c62c0d1a3c 100644
--- a/Sources/Services/AWSWorkMail/Tests/AWSWorkMailTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSWorkMail/Tests/AWSWorkMailTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSWorkMail
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -330,7 +331,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -369,7 +370,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -408,7 +409,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -447,7 +448,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSWorkMailMessageFlow/Sources/AWSWorkMailMessageFlow/Endpoints.swift b/Sources/Services/AWSWorkMailMessageFlow/Sources/AWSWorkMailMessageFlow/Endpoints.swift
index 55ad60acb70..2d4717e69da 100644
--- a/Sources/Services/AWSWorkMailMessageFlow/Sources/AWSWorkMailMessageFlow/Endpoints.swift
+++ b/Sources/Services/AWSWorkMailMessageFlow/Sources/AWSWorkMailMessageFlow/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSWorkMailMessageFlow/Tests/AWSWorkMailMessageFlowTests/EndpointResolverTest.swift b/Sources/Services/AWSWorkMailMessageFlow/Tests/AWSWorkMailMessageFlowTests/EndpointResolverTest.swift
index e751bd4254f..bc56fbe4fd8 100644
--- a/Sources/Services/AWSWorkMailMessageFlow/Tests/AWSWorkMailMessageFlowTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSWorkMailMessageFlow/Tests/AWSWorkMailMessageFlowTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSWorkMailMessageFlow
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSWorkSpaces/Sources/AWSWorkSpaces/Endpoints.swift b/Sources/Services/AWSWorkSpaces/Sources/AWSWorkSpaces/Endpoints.swift
index d8ac7c41cf0..2f0a31fc6ce 100644
--- a/Sources/Services/AWSWorkSpaces/Sources/AWSWorkSpaces/Endpoints.swift
+++ b/Sources/Services/AWSWorkSpaces/Sources/AWSWorkSpaces/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSWorkSpaces/Tests/AWSWorkSpacesTests/EndpointResolverTest.swift b/Sources/Services/AWSWorkSpaces/Tests/AWSWorkSpacesTests/EndpointResolverTest.swift
index 10693a3f6ae..7506d4f46b7 100644
--- a/Sources/Services/AWSWorkSpaces/Tests/AWSWorkSpacesTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSWorkSpaces/Tests/AWSWorkSpacesTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSWorkSpaces
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -610,7 +611,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -649,7 +650,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -688,7 +689,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -728,7 +729,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -748,7 +749,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSWorkSpacesThinClient/Sources/AWSWorkSpacesThinClient/Endpoints.swift b/Sources/Services/AWSWorkSpacesThinClient/Sources/AWSWorkSpacesThinClient/Endpoints.swift
index b1414c70064..acd25560df7 100644
--- a/Sources/Services/AWSWorkSpacesThinClient/Sources/AWSWorkSpacesThinClient/Endpoints.swift
+++ b/Sources/Services/AWSWorkSpacesThinClient/Sources/AWSWorkSpacesThinClient/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSWorkSpacesThinClient/Tests/AWSWorkSpacesThinClientTests/EndpointResolverTest.swift b/Sources/Services/AWSWorkSpacesThinClient/Tests/AWSWorkSpacesThinClientTests/EndpointResolverTest.swift
index be78b11dca7..2c9182be5da 100644
--- a/Sources/Services/AWSWorkSpacesThinClient/Tests/AWSWorkSpacesThinClientTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSWorkSpacesThinClient/Tests/AWSWorkSpacesThinClientTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSWorkSpacesThinClient
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -290,7 +291,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -329,7 +330,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -368,7 +369,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -407,7 +408,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -428,7 +429,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -448,7 +449,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSWorkSpacesWeb/Sources/AWSWorkSpacesWeb/Endpoints.swift b/Sources/Services/AWSWorkSpacesWeb/Sources/AWSWorkSpacesWeb/Endpoints.swift
index 46c531e64c5..0937031fecd 100644
--- a/Sources/Services/AWSWorkSpacesWeb/Sources/AWSWorkSpacesWeb/Endpoints.swift
+++ b/Sources/Services/AWSWorkSpacesWeb/Sources/AWSWorkSpacesWeb/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSWorkSpacesWeb/Tests/AWSWorkSpacesWebTests/EndpointResolverTest.swift b/Sources/Services/AWSWorkSpacesWeb/Tests/AWSWorkSpacesWebTests/EndpointResolverTest.swift
index 8fca1841af3..84ceab7c9f3 100644
--- a/Sources/Services/AWSWorkSpacesWeb/Tests/AWSWorkSpacesWebTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSWorkSpacesWeb/Tests/AWSWorkSpacesWebTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSWorkSpacesWeb
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -330,7 +331,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -369,7 +370,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -408,7 +409,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -447,7 +448,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -468,7 +469,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -488,7 +489,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/Sources/Services/AWSXRay/Sources/AWSXRay/Endpoints.swift b/Sources/Services/AWSXRay/Sources/AWSXRay/Endpoints.swift
index 92baf0fb843..b86fa482a1d 100644
--- a/Sources/Services/AWSXRay/Sources/AWSXRay/Endpoints.swift
+++ b/Sources/Services/AWSXRay/Sources/AWSXRay/Endpoints.swift
@@ -14,7 +14,7 @@ import struct ClientRuntime.DefaultEndpointResolver
 import struct ClientRuntime.StaticEndpointResolver
 import struct SmithyHTTPAPI.Endpoint
 
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     /// Override the endpoint used to send this request
     public let endpoint: Swift.String?
     /// The AWS region used to dispatch the request.
diff --git a/Sources/Services/AWSXRay/Tests/AWSXRayTests/EndpointResolverTest.swift b/Sources/Services/AWSXRay/Tests/AWSXRayTests/EndpointResolverTest.swift
index 3912a9f0f5e..6ec9cb6a04d 100644
--- a/Sources/Services/AWSXRay/Tests/AWSXRayTests/EndpointResolverTest.swift
+++ b/Sources/Services/AWSXRay/Tests/AWSXRayTests/EndpointResolverTest.swift
@@ -10,6 +10,7 @@
 @testable import AWSXRay
 import XCTest
 import enum ClientRuntime.EndpointError
+import enum SmithyHTTPAPI.EndpointPropertyValue
 import enum SmithyTestUtil.TestInitializer
 import struct SmithyHTTPAPI.Endpoint
 import struct SmithyHTTPAPI.Headers
@@ -31,7 +32,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -51,7 +52,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -71,7 +72,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -91,7 +92,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -111,7 +112,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -131,7 +132,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -151,7 +152,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -171,7 +172,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -191,7 +192,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -211,7 +212,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -231,7 +232,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -251,7 +252,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -271,7 +272,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -291,7 +292,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -311,7 +312,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -331,7 +332,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -351,7 +352,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -371,7 +372,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -391,7 +392,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -411,7 +412,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -431,7 +432,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -451,7 +452,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -471,7 +472,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -491,7 +492,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -511,7 +512,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -531,7 +532,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -551,7 +552,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -571,7 +572,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -591,7 +592,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -611,7 +612,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -631,7 +632,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -651,7 +652,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -671,7 +672,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -691,7 +692,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -711,7 +712,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -731,7 +732,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -751,7 +752,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -771,7 +772,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -791,7 +792,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -830,7 +831,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -869,7 +870,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -908,7 +909,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -947,7 +948,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -968,7 +969,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
@@ -988,7 +989,7 @@ class EndpointResolverTest: XCTestCase {
 
         let actual = try resolver.resolve(params: endpointParams)
 
-        let properties: [String: AnyHashable] =
+        let properties: [String: SmithyHTTPAPI.EndpointPropertyValue] =
             [:]
 
         let headers = SmithyHTTPAPI.Headers()
diff --git a/codegen/Package.swift b/codegen/Package.swift
index 054b671dba6..2f04ecaf778 100644
--- a/codegen/Package.swift
+++ b/codegen/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version:5.9
+// swift-tools-version:6.0
 
 //
 // Copyright Amazon.com Inc. or its affiliates.
diff --git a/codegen/protocol-test-codegen-local/Tests/swift-codegen/Tests/WaitersTests/WaiterTestUtils.swift b/codegen/protocol-test-codegen-local/Tests/swift-codegen/Tests/WaitersTests/WaiterTestUtils.swift
index ec45dfdf23c..3c61f7861d6 100644
--- a/codegen/protocol-test-codegen-local/Tests/swift-codegen/Tests/WaitersTests/WaiterTestUtils.swift
+++ b/codegen/protocol-test-codegen-local/Tests/swift-codegen/Tests/WaitersTests/WaiterTestUtils.swift
@@ -53,4 +53,4 @@ extension Swift.String: Swift.Error {
     var localizedString: String? { self }
 }
 
-var anInput = GetWidgetInput()
+let anInput = GetWidgetInput()
diff --git a/codegen/smithy-aws-swift-codegen/src/test/kotlin/software/amazon/smithy/aws/swift/codegen/EndpointParamsGeneratorTests.kt b/codegen/smithy-aws-swift-codegen/src/test/kotlin/software/amazon/smithy/aws/swift/codegen/EndpointParamsGeneratorTests.kt
index ce03d165d1c..918db876529 100644
--- a/codegen/smithy-aws-swift-codegen/src/test/kotlin/software/amazon/smithy/aws/swift/codegen/EndpointParamsGeneratorTests.kt
+++ b/codegen/smithy-aws-swift-codegen/src/test/kotlin/software/amazon/smithy/aws/swift/codegen/EndpointParamsGeneratorTests.kt
@@ -24,7 +24,7 @@ class EndpointParamsGeneratorTests {
         endpointParamsGenerator.render()
         val contents = TestUtils.getFileContents(context.manifest, "Sources/Example/Endpoints.swift")
         val expected = """
-public struct EndpointParams {
+public struct EndpointParams: Sendable {
     public let boolBar: Swift.Bool?
     public let boolBaz: Swift.String?
     public let boolFoo: Swift.Bool