Merge branch 'main' into completiondetails

Author: stephentoub

docs/concepts/transports/transports.md

@@ -137,8 +137,6 @@ app.MapMcp("/mcp");
 
 When using a custom route, Streamable HTTP clients should connect directly to that route (e.g., `https://host/mcp`), while SSE clients should connect to `{route}/sse` (e.g., `https://host/mcp/sse`).
 
-See the `ModelContextProtocol.AspNetCore` package [README](https://github.com/modelcontextprotocol/csharp-sdk/blob/main/src/ModelContextProtocol.AspNetCore/README.md) for more configuration options.
-
 ### SSE transport (legacy)
 
 The [SSE (Server-Sent Events)] transport is a legacy mechanism that uses unidirectional server-to-client streaming with a separate HTTP endpoint for client-to-server messages. New implementations should prefer Streamable HTTP.

package-lock.json

@@ -133,6 +133,13 @@ public McpSessionHandler(
         _outgoingMessageFilter = outgoingMessageFilter ?? (next => next);
         _logger = logger;
 
+        // Per the MCP spec, ping may be initiated by either party and must always be handled.
+        _requestHandlers.Set(
+            RequestMethods.Ping,
+            (request, _, cancellationToken) => new ValueTask<PingResult>(new PingResult()),
+            McpJsonUtilities.JsonContext.Default.JsonNode,
+            McpJsonUtilities.JsonContext.Default.PingResult);
+
         LogSessionCreated(EndpointName, _sessionId, _transportKind);
     }
 

src/ModelContextProtocol.Core/McpSessionHandler.cs

@@ -91,7 +91,6 @@ public McpServerImpl(ITransport transport, McpServerOptions options, ILoggerFact
         ConfigureLogging(options);
         ConfigureCompletion(options);
         ConfigureExperimental(options);
-        ConfigurePing();
 
         // Register any notification handlers that were provided.
         if (options.Handlers.NotificationHandlers is { } notificationHandlers)
@@ -204,14 +203,6 @@ public override async ValueTask DisposeAsync()
         await _sessionHandler.DisposeAsync().ConfigureAwait(false);
     }
 
-    private void ConfigurePing()
-    {
-        SetHandler(RequestMethods.Ping,
-            async (request, _) => new PingResult(),
-            McpJsonUtilities.JsonContext.Default.JsonNode,
-            McpJsonUtilities.JsonContext.Default.PingResult);
-    }
-
     private void ConfigureInitialize(McpServerOptions options)
     {
         _requestHandlers.Set(RequestMethods.Initialize,

src/ModelContextProtocol.Core/Server/McpServerImpl.cs

@@ -795,4 +795,16 @@ public async Task Completion_GracefulDisposal_CompletesWithNoException()
         var details = await client.Completion;
         Assert.Null(details.Exception);
     }
+
+    [Fact]
+    public async Task ServerCanPingClient()
+    {
+        await using McpClient client = await CreateMcpClientForServer();
+
+        var pingRequest = new JsonRpcRequest { Method = RequestMethods.Ping };
+        var response = await Server.SendRequestAsync(pingRequest, TestContext.Current.CancellationToken);
+
+        Assert.NotNull(response);
+        Assert.NotNull(response.Result);
+    }
 }