diff --git a/snapshots/input/syntax/src/overload.d.ts b/snapshots/input/syntax/src/overload.d.ts
index f263ed41..901135ed 100644
--- a/snapshots/input/syntax/src/overload.d.ts
+++ b/snapshots/input/syntax/src/overload.d.ts
@@ -1,3 +1,5 @@
+// format-options: showDocs
+
 export interface Overloader {
   onLiteral(param: 'a'): void
   onLiteral(param: 'b'): void
diff --git a/snapshots/output/syntax/src/overload.d.ts b/snapshots/output/syntax/src/overload.d.ts
index a9749c98..bd0bc9c6 100644
--- a/snapshots/output/syntax/src/overload.d.ts
+++ b/snapshots/output/syntax/src/overload.d.ts
@@ -1,11 +1,31 @@
 // language TypeScript
 // < definition syntax 1.0.0 src/`overload.d.ts`/
+//documentation ```ts
+//            > module "overload.d.ts"
+//            > ```
+
+// format-options: showDocs
 
 export interface Overloader {
 //               ^^^^^^^^^^ definition syntax 1.0.0 src/`overload.d.ts`/Overloader#
+//               documentation ```ts
+//                           > interface Overloader
+//                           > ```
   onLiteral(param: 'a'): void
 //^^^^^^^^^ definition syntax 1.0.0 src/`overload.d.ts`/Overloader#onLiteral().
+//documentation ```ts
+//            > (method) onLiteral(param: "a"): void
+//            > ```
+//documentation ```ts
+//            > (method) onLiteral(param: "b"): void
+//            > ```
 //          ^^^^^ definition syntax 1.0.0 src/`overload.d.ts`/Overloader#onLiteral().(param)
+//          documentation ```ts
+//                      > (parameter) param: "a"
+//                      > ```
+//          documentation ```ts
+//                      > (parameter) param: "b"
+//                      > ```
   onLiteral(param: 'b'): void
 //^^^^^^^^^ definition syntax 1.0.0 src/`overload.d.ts`/Overloader#onLiteral().
 //          ^^^^^ definition syntax 1.0.0 src/`overload.d.ts`/Overloader#onLiteral().(param)
diff --git a/src/FileIndexer.ts b/src/FileIndexer.ts
index 9b9f200c..9a7eac1b 100644
--- a/src/FileIndexer.ts
+++ b/src/FileIndexer.ts
@@ -25,6 +25,8 @@ export class FileIndexer {
   private localCounter = new Counter()
   private propertyCounters: Map<string, Counter> = new Map()
   private localSymbolTable: Map<ts.Node, ScipSymbol> = new Map()
+  private symbolInformation: Map<string, scip.scip.SymbolInformation> =
+    new Map()
   private workingDirectoryRegExp: RegExp
   constructor(
     public readonly checker: ts.TypeChecker,
@@ -78,7 +80,7 @@ export class FileIndexer {
     )
     const moduleName =
       this.sourceFile.moduleName || path.basename(this.sourceFile.fileName)
-    this.document.symbols.push(
+    this.pushSymbolInformation(
       new scip.scip.SymbolInformation({
         symbol: symbol.value,
         documentation: ['```ts\nmodule "' + moduleName + '"\n```'],
@@ -344,7 +346,9 @@ export class FileIndexer {
   ): void {
     const documentation = [
       '```ts\n' +
-        this.hideWorkingDirectory(this.signatureForDocumentation(node, sym)) +
+        this.hideWorkingDirectory(
+          this.signatureForDocumentation(node, sym, declaration)
+        ) +
         '\n```',
     ]
     const docstring = sym.getDocumentationComment(this.checker)
@@ -352,7 +356,7 @@ export class FileIndexer {
       documentation.push(ts.displayPartsToString(docstring))
     }
 
-    this.document.symbols.push(
+    this.pushSymbolInformation(
       new scip.scip.SymbolInformation({
         symbol: symbol.value,
         documentation,
@@ -362,6 +366,37 @@ export class FileIndexer {
     )
   }
 
+  private pushSymbolInformation(info: scip.scip.SymbolInformation): void {
+    const existing = this.symbolInformation.get(info.symbol)
+    if (!existing) {
+      this.symbolInformation.set(info.symbol, info)
+      this.document.symbols.push(info)
+      return
+    }
+
+    // Overload declarations share one SCIP symbol but can contribute distinct
+    // signatures and relationships. SCIP permits only one SymbolInformation
+    // entry per symbol, so merge that metadata into the first entry.
+    for (const documentation of info.documentation) {
+      if (!existing.documentation.includes(documentation)) {
+        existing.documentation.push(documentation)
+      }
+    }
+    for (const relationship of info.relationships) {
+      const previous = existing.relationships.find(
+        candidate => candidate.symbol === relationship.symbol
+      )
+      if (previous) {
+        previous.is_definition ||= relationship.is_definition
+        previous.is_reference ||= relationship.is_reference
+        previous.is_implementation ||= relationship.is_implementation
+        previous.is_type_definition ||= relationship.is_type_definition
+      } else {
+        existing.relationships.push(relationship)
+      }
+    }
+  }
+
   private pushOccurrence(occurrence: scip.scip.Occurrence): void {
     const lastOccurrence = this.document.occurrences.at(-1)
     if (lastOccurrence) {
@@ -634,28 +669,28 @@ export class FileIndexer {
     return undefined
   }
 
-  private signatureForDocumentation(node: ts.Node, sym: ts.Symbol): string {
+  private signatureForDocumentation(
+    node: ts.Node,
+    sym: ts.Symbol,
+    declaration: ts.Node
+  ): string {
     const kind = scriptElementKind(node, sym)
     const type = (): string =>
       this.checker.typeToString(this.checker.getTypeAtLocation(node))
     const asSignatureDeclaration = (
       node: ts.Node,
-      sym: ts.Symbol
+      declaration: ts.Node
     ): ts.SignatureDeclaration | undefined => {
-      const declaration = sym.declarations?.[0]
-      if (!declaration) {
-        return undefined
-      }
       return ts.isConstructorDeclaration(node)
         ? node
-        : ts.isFunctionDeclaration(declaration)
+        : ts.isFunctionDeclaration(declaration) ||
+            ts.isMethodDeclaration(declaration) ||
+            ts.isMethodSignature(declaration)
           ? declaration
-          : ts.isMethodDeclaration(declaration)
-            ? declaration
-            : undefined
+          : undefined
     }
     const signature = (): string | undefined => {
-      const signatureDeclaration = asSignatureDeclaration(node, sym)
+      const signatureDeclaration = asSignatureDeclaration(node, declaration)
       if (!signatureDeclaration) {
         return undefined
       }
diff --git a/src/main.test.ts b/src/main.test.ts
index d0d9a887..6114e291 100644
--- a/src/main.test.ts
+++ b/src/main.test.ts
@@ -75,6 +75,19 @@ for (const snapshotDirectory of snapshotDirectories) {
       throw new Error('empty LSIF index')
     }
     for (const document of index.documents) {
+      const symbols = new Set<string>()
+      const duplicateSymbols: string[] = []
+      for (const symbol of document.symbols) {
+        if (symbols.has(symbol.symbol)) {
+          duplicateSymbols.push(symbol.symbol)
+        }
+        symbols.add(symbol.symbol)
+      }
+      assert.equal(
+        duplicateSymbols,
+        [],
+        `${document.relative_path} should not contain duplicate SymbolInformation`
+      )
       assert.ok(
         document.language,
         `${document.relative_path} should have a SCIP document language`