fix: Move notification calls from internal _createRegisteredTool to public methods

The _createRegisteredTool() method was calling setToolRequestHandlers() and
sendToolListChanged() internally, which caused issues when registering tools
after server connection due to capability registration restrictions.

This moves the notification responsibility to the public registerTool() and
tool() methods, making tool registration consistent and allowing registration
after connection when capabilities have already been established.

Fixes memory leak warnings caused by rapid tool registration after connection.

Author: cameroncooke

src/server/mcp.test.ts

@@ -4290,4 +4290,120 @@ describe("elicitInput()", () => {
       text: "No booking made. Original date not available."
     }]);
   });
+
+  /***
+   * Test: Bulk Tool Registration - Memory Leak Prevention
+   */
+  test("should handle multiple tool registrations without memory leak", async () => {
+    const mcpServer = new McpServer({
+      name: "test server",
+      version: "1.0",
+    });
+
+    // Register first tool before connection (should work fine)
+    mcpServer.tool("tool1", async () => ({
+      content: [{ type: "text", text: "Tool 1" }]
+    }));
+
+    const notifications: Notification[] = []
+    const client = new Client({
+      name: "test client",
+      version: "1.0",
+    });
+    client.fallbackNotificationHandler = async (notification) => {
+      notifications.push(notification)
+    }
+
+    const [clientTransport, serverTransport] =
+      InMemoryTransport.createLinkedPair();
+
+    await Promise.all([
+      client.connect(clientTransport),
+      mcpServer.connect(serverTransport),
+    ]);
+
+    // Clear any initial notifications
+    notifications.length = 0;
+
+    // This should work since capabilities were already registered during first tool
+    mcpServer.tool("tool2", async () => ({
+      content: [{ type: "text", text: "Tool 2" }]
+    }));
+
+    // Yield event loop to let notifications process
+    await new Promise(process.nextTick);
+
+    // Should have sent exactly one notification for the second tool
+    expect(notifications).toHaveLength(1);
+    expect(notifications[0]).toMatchObject({
+      method: "notifications/tools/list_changed",
+    });
+
+    // Verify both tools are registered
+    const toolsResult = await client.request(
+      { method: "tools/list" },
+      ListToolsResultSchema,
+    );
+    expect(toolsResult.tools).toHaveLength(2);
+    expect(toolsResult.tools.map(t => t.name).sort()).toEqual(["tool1", "tool2"]);
+  });
+
+  /***
+   * Test: registerTool() should work after connection (fixed behavior)
+   */
+  test("registerTool() should work after connection", async () => {
+    const mcpServer = new McpServer({
+      name: "test server",
+      version: "1.0",
+    });
+
+    // Register first tool before connection to establish capabilities
+    mcpServer.tool("tool1", async () => ({
+      content: [{ type: "text", text: "Tool 1" }]
+    }));
+
+    const notifications: Notification[] = []
+    const client = new Client({
+      name: "test client", 
+      version: "1.0",
+    });
+    client.fallbackNotificationHandler = async (notification) => {
+      notifications.push(notification)
+    }
+
+    const [clientTransport, serverTransport] =
+      InMemoryTransport.createLinkedPair();
+
+    await Promise.all([
+      client.connect(clientTransport),
+      mcpServer.connect(serverTransport),
+    ]);
+
+    // Clear any initial notifications
+    notifications.length = 0;
+
+    // This should now work after the fix
+    mcpServer.registerTool("test2", {
+      description: "Test tool 2"
+    }, async () => ({
+      content: [{ type: "text", text: "Test 2" }]
+    }));
+
+    // Yield event loop to let notifications process
+    await new Promise(process.nextTick);
+
+    // Should have sent exactly one notification
+    expect(notifications).toHaveLength(1);
+    expect(notifications[0]).toMatchObject({
+      method: "notifications/tools/list_changed",
+    });
+
+    // Verify both tools are registered
+    const toolsResult = await client.request(
+      { method: "tools/list" },
+      ListToolsResultSchema,
+    );
+    expect(toolsResult.tools).toHaveLength(2);
+    expect(toolsResult.tools.map(t => t.name).sort()).toEqual(["test2", "tool1"]);
+  });
 });

src/server/mcp.ts

@@ -803,9 +803,6 @@ export class McpServer {
     };
     this._registeredTools[name] = registeredTool;
 
-    this.setToolRequestHandlers();
-    this.sendToolListChanged()
-
     return registeredTool
   }
 
@@ -914,7 +911,12 @@ export class McpServer {
     }
     const callback = rest[0] as ToolCallback<ZodRawShape | undefined>;
 
-    return this._createRegisteredTool(name, undefined, description, inputSchema, outputSchema, annotations, callback)
+    const result = this._createRegisteredTool(name, undefined, description, inputSchema, outputSchema, annotations, callback);
+    
+    this.setToolRequestHandlers();
+    this.sendToolListChanged();
+
+    return result;
   }
 
   /**
@@ -937,7 +939,7 @@ export class McpServer {
 
     const { title, description, inputSchema, outputSchema, annotations } = config;
 
-    return this._createRegisteredTool(
+    const result = this._createRegisteredTool(
       name,
       title,
       description,
@@ -946,6 +948,11 @@ export class McpServer {
       annotations,
       cb as ToolCallback<ZodRawShape | undefined>
     );
+
+    this.setToolRequestHandlers();
+    this.sendToolListChanged();
+
+    return result;
   }
 
   /**