Support [Tags] on client events for OpenAPI grouping

Client event methods can now be decorated with [Tags] to control their grouping in the generated OpenAPI document. If present, the specified tag(s) override the default "{HubName} Events" tag. Implementation, documentation, and tests have been updated to reflect and verify this behavior.

Author: icnocop

README.md

@@ -252,7 +252,8 @@ Explicit `TagDescriptions` always take precedence over XML summary fallback.
 |--------|----------|
 | Hub class (default) | Hub name without `Hub` suffix (e.g., `ChatHub` → `"Chat"`) |
 | `[Tags("group")]` on hub class or method | Specified tag name |
-| Client events (`Hub<TClient>`) | `"{HubName} Events"` (e.g., `"Chat Events"`) |
+| Client events (`Hub<TClient>`) default | `"{HubName} Events"` (e.g., `"Chat Events"`) |
+| `[Tags("group")]` on client interface method | Specified tag name (overrides default) |
 
 ## Request Body Schema
 

samples/SignalR.OpenApi.Sample/Hubs/IChatClient.cs

@@ -1,5 +1,7 @@
 // Copyright (c) SignalR.OpenApi Contributors. Licensed under the MIT License.
 
+using Microsoft.AspNetCore.Http;
+
 namespace SignalR.OpenApi.Sample.Hubs;
 
 /// <summary>
@@ -20,6 +22,7 @@ public interface IChatClient
     /// </summary>
     /// <param name="user">The user who connected.</param>
     /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+    [Tags("Presence")]
     Task UserConnected(string user);
 
     /// <summary>
@@ -28,5 +31,6 @@ public interface IChatClient
     /// </summary>
     /// <param name="notification">The notification that was received.</param>
     /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+    [Tags("Notifications")]
     Task ReceiveNotification(Notification notification);
 }

src/SignalR.OpenApi/Discovery/ReflectionHubDiscoverer.cs

@@ -441,6 +441,7 @@ private IReadOnlyList<SignalRClientEventInfo> DiscoverClientEvents(Type clientIn
                 Name = m.Name,
                 Summary = this.GetXmlSummary(m),
                 Description = this.GetXmlRemarks(m),
+                Tags = m.GetCustomAttribute<TagsAttribute>()?.Tags.ToList() ?? [],
                 Parameters = m.GetParameters()
                     .Select(p => new SignalRParameterInfo
                     {

src/SignalR.OpenApi/Generation/SignalROpenApiDocumentGenerator.cs

@@ -1014,7 +1014,9 @@ private void AddClientEventOperations(OpenApiDocument document, SignalRHubInfo h
 
             var operation = new OpenApiOperation
             {
-                Tags = [new OpenApiTag { Name = $"{hub.Name} Events" }],
+                Tags = clientEvent.Tags.Count > 0
+                    ? clientEvent.Tags.Select(t => new OpenApiTag { Name = t }).ToList()
+                    : [new OpenApiTag { Name = $"{hub.Name} Events" }],
                 Summary = clientEvent.Summary ?? $"Client event: {clientEvent.Name}",
                 Description = clientEvent.Description ?? "Server-to-client callback. Subscribe to this event to receive notifications.",
                 OperationId = $"{hub.Name}_Event_{clientEvent.Name}",

src/SignalR.OpenApi/Models/SignalRClientEventInfo.cs

@@ -22,6 +22,12 @@ public sealed class SignalRClientEventInfo
     /// </summary>
     public string? Description { get; set; }
 
+    /// <summary>
+    /// Gets or sets the tags for grouping in the OpenAPI document.
+    /// When empty, the generator falls back to the default "{HubName} Events" tag.
+    /// </summary>
+    public IReadOnlyList<string> Tags { get; set; } = [];
+
     /// <summary>
     /// Gets or sets the parameter types of the client event.
     /// </summary>

test/SignalR.OpenApi.Tests/ReflectionHubDiscovererTests.cs

@@ -309,6 +309,34 @@ public void DiscoverHubs_InheritDoc_ResolvesXmlDocsFromInterface()
         Assert.AreEqual("The user's name.", nameParam.Description);
     }
 
+    /// <summary>
+    /// Verifies Tags attribute is read from client event methods.
+    /// </summary>
+    [TestMethod]
+    public void DiscoverHubs_ReadsTagsAttributeOnClientEvent()
+    {
+        var discoverer = CreateDiscoverer();
+        var hubs = discoverer.DiscoverHubs();
+
+        var typed = hubs.First(h => h.HubType == typeof(TypedChatHub));
+        var userJoined = typed.ClientEvents.First(e => e.Name == "UserJoined");
+        CollectionAssert.Contains(userJoined.Tags.ToList(), "Presence");
+    }
+
+    /// <summary>
+    /// Verifies client events without Tags attribute have empty tags.
+    /// </summary>
+    [TestMethod]
+    public void DiscoverHubs_ClientEventWithoutTagsAttribute_HasEmptyTags()
+    {
+        var discoverer = CreateDiscoverer();
+        var hubs = discoverer.DiscoverHubs();
+
+        var typed = hubs.First(h => h.HubType == typeof(TypedChatHub));
+        var receiveMessage = typed.ClientEvents.First(e => e.Name == "ReceiveMessage");
+        Assert.AreEqual(0, receiveMessage.Tags.Count);
+    }
+
     private static ReflectionHubDiscoverer CreateDiscoverer(Action<SignalROpenApiOptions>? configure = null)
     {
         var options = new SignalROpenApiOptions

test/SignalR.OpenApi.Tests/SignalROpenApiDocumentGeneratorTests.cs

@@ -1125,6 +1125,41 @@ public void GenerateDocument_IncludesClientEventTags()
         CollectionAssert.Contains(tagNames, "TypedChat Events");
     }
 
+    /// <summary>
+    /// Verifies that a client event with [Tags] uses the custom tag instead of the default.
+    /// </summary>
+    [TestMethod]
+    public void GenerateDocument_ClientEventWithTagsAttribute_UsesCustomTag()
+    {
+        var (discoverer, generator) = CreateServices();
+        var hubs = discoverer.DiscoverHubs();
+        var doc = generator.GenerateDocument(hubs);
+
+        var userJoinedPath = doc.Paths["/hubs/TypedChat/events/UserJoined"];
+        var operation = userJoinedPath.Operations[OperationType.Get];
+        var tagNames = operation.Tags.Select(t => t.Name).ToList();
+
+        CollectionAssert.Contains(tagNames, "Presence");
+        CollectionAssert.DoesNotContain(tagNames, "TypedChat Events");
+    }
+
+    /// <summary>
+    /// Verifies that a client event without [Tags] falls back to the default "{HubName} Events" tag.
+    /// </summary>
+    [TestMethod]
+    public void GenerateDocument_ClientEventWithoutTagsAttribute_UsesDefaultTag()
+    {
+        var (discoverer, generator) = CreateServices();
+        var hubs = discoverer.DiscoverHubs();
+        var doc = generator.GenerateDocument(hubs);
+
+        var receiveMessagePath = doc.Paths["/hubs/TypedChat/events/ReceiveMessage"];
+        var operation = receiveMessagePath.Operations[OperationType.Get];
+        var tagNames = operation.Tags.Select(t => t.Name).ToList();
+
+        CollectionAssert.Contains(tagNames, "TypedChat Events");
+    }
+
     /// <summary>
     /// Verifies that document tags are deduplicated when multiple methods share the same tag.
     /// </summary>

test/SignalR.OpenApi.Tests/TestHubs/IChatClient.cs

@@ -1,5 +1,7 @@
 // Copyright (c) SignalR.OpenApi Contributors. Licensed under the MIT License.
 
+using Microsoft.AspNetCore.Http;
+
 namespace SignalR.OpenApi.Tests.TestHubs;
 
 /// <summary>
@@ -20,6 +22,7 @@ public interface IChatClient
     /// </summary>
     /// <param name="user">The user who joined.</param>
     /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+    [Tags("Presence")]
     Task UserJoined(string user);
 
     /// <summary>