fix: wait for initialization to complete before listing tools (#886)

src/mcp/server.ts

@@ -54,6 +54,7 @@ export function createServer(backend: ServerBackend, runHeartbeat: boolean): Ser
 
   server.setRequestHandler(ListToolsRequestSchema, async () => {
     serverDebug('listTools');
+    await initializedPromise;
     const tools = await backend.listTools();
     return { tools };
   });

tests/fixtures.ts

@@ -47,6 +47,7 @@ type TestFixtures = {
     args?: string[],
     config?: Config,
     roots?: { name: string, uri: string }[],
+    rootsResponseDelay?: number,
   }) => Promise<{ client: Client, stderr: () => string }>;
   wsEndpoint: string;
   cdpServer: CDPServer;
@@ -89,6 +90,8 @@ export const test = baseTest.extend<TestFixtures & TestOptions, WorkerFixtures>(
       client = new Client({ name: options?.clientName ?? 'test', version: '1.0.0' }, options?.roots ? { capabilities: { roots: {} } } : undefined);
       if (options?.roots) {
         client.setRequestHandler(ListRootsRequestSchema, async request => {
+          if (options.rootsResponseDelay)
+            await new Promise(resolve => setTimeout(resolve, options.rootsResponseDelay));
           return {
             roots: options.roots,
           };

tests/roots.spec.ts

@@ -50,7 +50,7 @@ for (const mode of ['default', 'proxy']) {
     });
 
 
-    test('check that trace is saved in workspace', async ({ startClient, server, mcpMode }, testInfo) => {
+    test('check that trace is saved in workspace', async ({ startClient, server }, testInfo) => {
       const rootPath = testInfo.outputPath('workspace');
       const { client } = await startClient({
         args: ['--save-trace', ...extraArgs],
@@ -73,5 +73,15 @@ for (const mode of ['default', 'proxy']) {
       const [file] = await fs.promises.readdir(path.join(rootPath, '.playwright-mcp'));
       expect(file).toContain('traces');
     });
+
+    test('should list all tools when listRoots is slow', async ({ startClient, server }, testInfo) => {
+      const { client } = await startClient({
+        clientName: 'Visual Studio Code', // Simulate VS Code client, roots only work with it
+        roots: [],
+        rootsResponseDelay: 1000,
+      });
+      const tools = await client.listTools();
+      expect(tools.tools.length).toBeGreaterThan(20);
+    });
   });
 }