Merge branch 'main' into request-propagation-in-tools

Author: KKonstantinov

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@modelcontextprotocol/sdk",
-  "version": "1.12.2",
+  "version": "1.12.3",
   "description": "Model Context Protocol implementation for TypeScript",
   "license": "MIT",
   "author": "Anthropic, PBC (https://anthropic.com)",

src/client/index.ts

@@ -165,6 +165,10 @@ export class Client<
 
       this._serverCapabilities = result.capabilities;
       this._serverVersion = result.serverInfo;
+      // HTTP transports must set the protocol version in each header after initialization.
+      if (transport.setProtocolVersion) {
+        transport.setProtocolVersion(result.protocolVersion);
+      }
 
       this._instructions = result.instructions;
 

src/client/sse.ts

@@ -62,6 +62,7 @@ export class SSEClientTransport implements Transport {
   private _eventSourceInit?: EventSourceInit;
   private _requestInit?: RequestInit;
   private _authProvider?: OAuthClientProvider;
+  private _protocolVersion?: string;
 
   onclose?: () => void;
   onerror?: (error: Error) => void;
@@ -99,13 +100,18 @@ export class SSEClientTransport implements Transport {
   }
 
   private async _commonHeaders(): Promise<HeadersInit> {
-    const headers: HeadersInit = { ...this._requestInit?.headers };
+    const headers = {
+      ...this._requestInit?.headers,
+    } as HeadersInit & Record<string, string>;
     if (this._authProvider) {
       const tokens = await this._authProvider.tokens();
       if (tokens) {
-        (headers as Record<string, string>)["Authorization"] = `Bearer ${tokens.access_token}`;
+        headers["Authorization"] = `Bearer ${tokens.access_token}`;
       }
     }
+    if (this._protocolVersion) {
+      headers["mcp-protocol-version"] = this._protocolVersion;
+    }
 
     return headers;
   }
@@ -214,7 +220,7 @@ export class SSEClientTransport implements Transport {
 
     try {
       const commonHeaders = await this._commonHeaders();
-      const headers = new Headers({ ...commonHeaders, ...this._requestInit?.headers });
+      const headers = new Headers(commonHeaders);
       headers.set("content-type", "application/json");
       const init = {
         ...this._requestInit,
@@ -249,4 +255,8 @@ export class SSEClientTransport implements Transport {
       throw error;
     }
   }
+
+  setProtocolVersion(version: string): void {
+    this._protocolVersion = version;
+  }
 }

src/client/streamableHttp.ts

@@ -124,6 +124,7 @@ export class StreamableHTTPClientTransport implements Transport {
   private _authProvider?: OAuthClientProvider;
   private _sessionId?: string;
   private _reconnectionOptions: StreamableHTTPReconnectionOptions;
+  private _protocolVersion?: string;
 
   onclose?: () => void;
   onerror?: (error: Error) => void;
@@ -162,7 +163,7 @@ export class StreamableHTTPClientTransport implements Transport {
   }
 
   private async _commonHeaders(): Promise<Headers> {
-    const headers: HeadersInit = {};
+    const headers: HeadersInit & Record<string, string> = {};
     if (this._authProvider) {
       const tokens = await this._authProvider.tokens();
       if (tokens) {
@@ -173,6 +174,9 @@ export class StreamableHTTPClientTransport implements Transport {
     if (this._sessionId) {
       headers["mcp-session-id"] = this._sessionId;
     }
+    if (this._protocolVersion) {
+      headers["mcp-protocol-version"] = this._protocolVersion;
+    }
 
     return new Headers(
       { ...headers, ...this._requestInit?.headers }
@@ -516,4 +520,11 @@ export class StreamableHTTPClientTransport implements Transport {
       throw error;
     }
   }
+
+  setProtocolVersion(version: string): void {
+    this._protocolVersion = version;
+  }
+  get protocolVersion(): string | undefined {
+    return this._protocolVersion;
+  }
 }

src/integration-tests/stateManagementStreamableHttp.test.ts

@@ -5,7 +5,7 @@ import { Client } from '../client/index.js';
 import { StreamableHTTPClientTransport } from '../client/streamableHttp.js';
 import { McpServer } from '../server/mcp.js';
 import { StreamableHTTPServerTransport } from '../server/streamableHttp.js';
-import { CallToolResultSchema, ListToolsResultSchema, ListResourcesResultSchema, ListPromptsResultSchema } from '../types.js';
+import { CallToolResultSchema, ListToolsResultSchema, ListResourcesResultSchema, ListPromptsResultSchema, DEFAULT_NEGOTIATED_PROTOCOL_VERSION } from '../types.js';
 import { z } from 'zod';
 
 describe('Streamable HTTP Transport Session Management', () => {
@@ -211,6 +211,27 @@ describe('Streamable HTTP Transport Session Management', () => {
       // Clean up
       await transport.close();
     });
+
+    it('should set protocol version after connecting', async () => {
+      // Create and connect a client
+      const client = new Client({
+        name: 'test-client',
+        version: '1.0.0'
+      });
+
+      const transport = new StreamableHTTPClientTransport(baseUrl);
+      
+      // Verify protocol version is not set before connecting
+      expect(transport.protocolVersion).toBeUndefined();
+      
+      await client.connect(transport);
+      
+      // Verify protocol version is set after connecting
+      expect(transport.protocolVersion).toBe(DEFAULT_NEGOTIATED_PROTOCOL_VERSION);
+      
+      // Clean up
+      await transport.close();
+    });
   });
 
   describe('Stateful Mode', () => {

src/server/index.ts

@@ -251,10 +251,12 @@ export class Server<
     this._clientCapabilities = request.params.capabilities;
     this._clientVersion = request.params.clientInfo;
 
-    return {
-      protocolVersion: SUPPORTED_PROTOCOL_VERSIONS.includes(requestedVersion)
+    const protocolVersion = SUPPORTED_PROTOCOL_VERSIONS.includes(requestedVersion)
         ? requestedVersion
-        : LATEST_PROTOCOL_VERSION,
+        : LATEST_PROTOCOL_VERSION;
+
+    return {
+      protocolVersion,
       capabilities: this.getCapabilities(),
       serverInfo: this._serverInfo,
       ...(this._instructions && { instructions: this._instructions }),

src/server/mcp.test.ts

@@ -3466,4 +3466,144 @@ describe("prompt()", () => {
     expect(typeof receivedRequestId === 'string' || typeof receivedRequestId === 'number').toBe(true);
     expect(result.messages[0].content.text).toContain("Received request ID:");
   });
+
+  /***
+   * Test: Resource Template Metadata Priority
+   */
+  test("should prioritize individual resource metadata over template metadata", async () => {
+    const mcpServer = new McpServer({
+      name: "test server",
+      version: "1.0",
+    });
+    const client = new Client({
+      name: "test client",
+      version: "1.0",
+    });
+
+    mcpServer.resource(
+      "test",
+      new ResourceTemplate("test://resource/{id}", {
+        list: async () => ({
+          resources: [
+            {
+              name: "Resource 1",
+              uri: "test://resource/1",
+              description: "Individual resource description",
+              mimeType: "text/plain",
+            },
+            {
+              name: "Resource 2",
+              uri: "test://resource/2",
+              // This resource has no description or mimeType
+            },
+          ],
+        }),
+      }),
+      {
+        description: "Template description",
+        mimeType: "application/json",
+      },
+      async (uri) => ({
+        contents: [
+          {
+            uri: uri.href,
+            text: "Test content",
+          },
+        ],
+      }),
+    );
+
+    const [clientTransport, serverTransport] =
+      InMemoryTransport.createLinkedPair();
+
+    await Promise.all([
+      client.connect(clientTransport),
+      mcpServer.server.connect(serverTransport),
+    ]);
+
+    const result = await client.request(
+      {
+        method: "resources/list",
+      },
+      ListResourcesResultSchema,
+    );
+
+    expect(result.resources).toHaveLength(2);
+    
+    // Resource 1 should have its own metadata
+    expect(result.resources[0].name).toBe("Resource 1");
+    expect(result.resources[0].description).toBe("Individual resource description");
+    expect(result.resources[0].mimeType).toBe("text/plain");
+    
+    // Resource 2 should inherit template metadata
+    expect(result.resources[1].name).toBe("Resource 2");
+    expect(result.resources[1].description).toBe("Template description");
+    expect(result.resources[1].mimeType).toBe("application/json");
+  });
+
+  /***
+   * Test: Resource Template Metadata Overrides All Fields
+   */
+  test("should allow resource to override all template metadata fields", async () => {
+    const mcpServer = new McpServer({
+      name: "test server",
+      version: "1.0",
+    });
+    const client = new Client({
+      name: "test client",
+      version: "1.0",
+    });
+
+    mcpServer.resource(
+      "test",
+      new ResourceTemplate("test://resource/{id}", {
+        list: async () => ({
+          resources: [
+            {
+              name: "Overridden Name",
+              uri: "test://resource/1",
+              description: "Overridden description",
+              mimeType: "text/markdown",
+              // Add any other metadata fields if they exist
+            },
+          ],
+        }),
+      }),
+      {
+        name: "Template Name",
+        description: "Template description",
+        mimeType: "application/json",
+      },
+      async (uri) => ({
+        contents: [
+          {
+            uri: uri.href,
+            text: "Test content",
+          },
+        ],
+      }),
+    );
+
+    const [clientTransport, serverTransport] =
+      InMemoryTransport.createLinkedPair();
+
+    await Promise.all([
+      client.connect(clientTransport),
+      mcpServer.server.connect(serverTransport),
+    ]);
+
+    const result = await client.request(
+      {
+        method: "resources/list",
+      },
+      ListResourcesResultSchema,
+    );
+
+    expect(result.resources).toHaveLength(1);
+    
+    // All fields should be from the individual resource, not the template
+    expect(result.resources[0].name).toBe("Overridden Name");
+    expect(result.resources[0].description).toBe("Overridden description");
+    expect(result.resources[0].mimeType).toBe("text/markdown");
+  });
 });

src/server/mcp.ts

@@ -373,8 +373,9 @@ export class McpServer {
           const result = await template.resourceTemplate.listCallback(extra);
           for (const resource of result.resources) {
             templateResources.push({
-              ...resource,
               ...template.metadata,
+              // the defined resource metadata should override the template metadata if present
+              ...resource,
             });
           }
         }

src/server/sse.ts

@@ -18,7 +18,6 @@ const MAXIMUM_MESSAGE_SIZE = "4mb";
 export class SSEServerTransport implements Transport {
   private _sseResponse?: ServerResponse;
   private _sessionId: string;
-
   onclose?: () => void;
   onerror?: (error: Error) => void;
   onmessage?: (message: JSONRPCMessage, extra: { authInfo?: AuthInfo, requestInfo: RequestInfo }) => void;