Fix registering multiple tools/resources/prompts

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@modelcontextprotocol/sdk",
-  "version": "1.3.0",
+  "version": "1.3.1",
   "description": "Model Context Protocol implementation for TypeScript",
   "license": "MIT",
   "author": "Anthropic, PBC (https://anthropic.com)",

src/server/mcp.test.ts

@@ -310,6 +310,19 @@ describe("tool()", () => {
     }).toThrow(/already registered/);
   });
 
+  test("should allow registering multiple tools", () => {
+    const mcpServer = new McpServer({
+      name: "test server",
+      version: "1.0",
+    });
+
+    // This should succeed
+    mcpServer.tool("tool1", () => ({ content: [] }));
+
+    // This should also succeed and not throw about request handlers
+    mcpServer.tool("tool2", () => ({ content: [] }));
+  });
+
   test("should allow client to call server tools", async () => {
     const mcpServer = new McpServer({
       name: "test server",
@@ -734,6 +747,33 @@ describe("resource()", () => {
     }).toThrow(/already registered/);
   });
 
+  test("should allow registering multiple resources", () => {
+    const mcpServer = new McpServer({
+      name: "test server",
+      version: "1.0",
+    });
+
+    // This should succeed
+    mcpServer.resource("resource1", "test://resource1", async () => ({
+      contents: [
+        {
+          uri: "test://resource1",
+          text: "Test content 1",
+        },
+      ],
+    }));
+
+    // This should also succeed and not throw about request handlers
+    mcpServer.resource("resource2", "test://resource2", async () => ({
+      contents: [
+        {
+          uri: "test://resource2",
+          text: "Test content 2",
+        },
+      ],
+    }));
+  });
+
   test("should prevent duplicate resource template registration", () => {
     const mcpServer = new McpServer({
       name: "test server",
@@ -1210,6 +1250,39 @@ describe("prompt()", () => {
     }).toThrow(/already registered/);
   });
 
+  test("should allow registering multiple prompts", () => {
+    const mcpServer = new McpServer({
+      name: "test server",
+      version: "1.0",
+    });
+
+    // This should succeed
+    mcpServer.prompt("prompt1", async () => ({
+      messages: [
+        {
+          role: "assistant",
+          content: {
+            type: "text",
+            text: "Test response 1",
+          },
+        },
+      ],
+    }));
+
+    // This should also succeed and not throw about request handlers
+    mcpServer.prompt("prompt2", async () => ({
+      messages: [
+        {
+          role: "assistant",
+          content: {
+            type: "text",
+            text: "Test response 2",
+          },
+        },
+      ],
+    }));
+  });
+
   test("should throw McpError for invalid prompt name", async () => {
     const mcpServer = new McpServer({
       name: "test server",

src/server/mcp.ts

@@ -81,7 +81,13 @@ export class McpServer {
     await this.server.close();
   }
 
+  private _toolHandlersInitialized = false;
+
   private setToolRequestHandlers() {
+    if (this._toolHandlersInitialized) {
+      return;
+    }
+
     this.server.assertCanSetRequestHandler(
       ListToolsRequestSchema.shape.method.value,
     );
@@ -165,6 +171,8 @@ export class McpServer {
         }
       },
     );
+
+    this._toolHandlersInitialized = true;
   }
 
   private setCompletionRequestHandler() {
@@ -249,7 +257,13 @@ export class McpServer {
     return createCompletionResult(suggestions);
   }
 
+  private _resourceHandlersInitialized = false;
+
   private setResourceRequestHandlers() {
+    if (this._resourceHandlersInitialized) {
+      return;
+    }
+
     this.server.assertCanSetRequestHandler(
       ListResourcesRequestSchema.shape.method.value,
     );
@@ -342,9 +356,17 @@ export class McpServer {
     );
 
     this.setCompletionRequestHandler();
+
+    this._resourceHandlersInitialized = true;
   }
 
+  private _promptHandlersInitialized = false;
+
   private setPromptRequestHandlers() {
+    if (this._promptHandlersInitialized) {
+      return;
+    }
+
     this.server.assertCanSetRequestHandler(
       ListPromptsRequestSchema.shape.method.value,
     );
@@ -406,6 +428,8 @@ export class McpServer {
     );
 
     this.setCompletionRequestHandler();
+
+    this._promptHandlersInitialized = true;
   }
 
   /**