chore: mark v0.0.26 (#441)

Ref https://github.com/microsoft/playwright-mcp/issues/439

README.md

@@ -146,6 +146,8 @@ Playwright MCP server supports following arguments. They can be provided in the
                                example ".com,chromium.org,.domain.com"
   --proxy-server <proxy>       specify proxy server, for example
                                "http://myproxy:3128" or "socks5://myproxy:8080"
+  --save-trace                 Whether to save the Playwright Trace of the
+                               session into the output directory.
   --storage-state <path>       path to the storage state file for isolated
                                sessions.
   --user-agent <ua string>     specify user agent string

config.d.ts

@@ -94,6 +94,11 @@ export type Config = {
    */
   vision?: boolean;
 
+  /**
+   * Whether to save the Playwright trace of the session into the output directory.
+   */
+  saveTrace?: boolean;
+
   /**
    * The directory to save output files.
    */

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "@playwright/mcp",
-  "version": "0.0.25",
+  "version": "0.0.26",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@playwright/mcp",
-      "version": "0.0.25",
+      "version": "0.0.26",
       "license": "Apache-2.0",
       "dependencies": {
         "@modelcontextprotocol/sdk": "^1.11.0",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@playwright/mcp",
-  "version": "0.0.25",
+  "version": "0.0.26",
   "description": "Playwright Tools for MCP",
   "type": "module",
   "repository": {

src/config.ts

@@ -44,6 +44,7 @@ export type CLIOptions = {
   port?: number;
   proxyBypass?: string;
   proxyServer?: string;
+  saveTrace?: boolean;
   storageState?: string;
   userAgent?: string;
   userDataDir?: string;
@@ -51,7 +52,7 @@ export type CLIOptions = {
   vision?: boolean;
 };
 
-const defaultConfig: Config = {
+const defaultConfig: FullConfig = {
   browser: {
     browserName: 'chromium',
     launchOptions: {
@@ -67,12 +68,33 @@ const defaultConfig: Config = {
     allowedOrigins: undefined,
     blockedOrigins: undefined,
   },
+  outputDir: path.join(os.tmpdir(), 'playwright-mcp-output', sanitizeForFilePath(new Date().toISOString())),
 };
 
-export async function resolveConfig(cliOptions: CLIOptions): Promise<Config> {
-  const config = await loadConfig(cliOptions.config);
+type BrowserUserConfig = NonNullable<Config['browser']>;
+
+export type FullConfig = Config & {
+  browser: BrowserUserConfig & {
+    browserName: NonNullable<BrowserUserConfig['browserName']>;
+    launchOptions: NonNullable<BrowserUserConfig['launchOptions']>;
+    contextOptions: NonNullable<BrowserUserConfig['contextOptions']>;
+  },
+  network: NonNullable<Config['network']>,
+  outputDir: string;
+};
+
+export async function resolveConfig(config: Config): Promise<FullConfig> {
+  return mergeConfig(defaultConfig, config);
+}
+
+export async function resolveCLIConfig(cliOptions: CLIOptions): Promise<FullConfig> {
+  const configInFile = await loadConfig(cliOptions.config);
   const cliOverrides = await configFromCLIOptions(cliOptions);
-  return mergeConfig(defaultConfig, mergeConfig(config, cliOverrides));
+  const result = mergeConfig(mergeConfig(defaultConfig, configInFile), cliOverrides);
+  // Derive artifact output directory from config.outputDir
+  if (result.saveTrace)
+    result.browser.launchOptions.tracesDir = path.join(result.outputDir, 'traces');
+  return result;
 }
 
 export async function configFromCLIOptions(cliOptions: CLIOptions): Promise<Config> {
@@ -169,6 +191,7 @@ export async function configFromCLIOptions(cliOptions: CLIOptions): Promise<Conf
       allowedOrigins: cliOptions.allowedOrigins,
       blockedOrigins: cliOptions.blockedOrigins,
     },
+    saveTrace: cliOptions.saveTrace,
     outputDir: cliOptions.outputDir,
   };
 
@@ -202,11 +225,10 @@ async function loadConfig(configFile: string | undefined): Promise<Config> {
   }
 }
 
-export async function outputFile(config: Config, name: string): Promise<string> {
-  const result = config.outputDir ?? os.tmpdir();
-  await fs.promises.mkdir(result, { recursive: true });
+export async function outputFile(config: FullConfig, name: string): Promise<string> {
+  await fs.promises.mkdir(config.outputDir, { recursive: true });
   const fileName = sanitizeForFilePath(name);
-  return path.join(result, fileName);
+  return path.join(config.outputDir, fileName);
 }
 
 function pickDefined<T extends object>(obj: T | undefined): Partial<T> {
@@ -215,10 +237,10 @@ function pickDefined<T extends object>(obj: T | undefined): Partial<T> {
   ) as Partial<T>;
 }
 
-function mergeConfig(base: Config, overrides: Config): Config {
-  const browser: Config['browser'] = {
-    ...pickDefined(base.browser),
-    ...pickDefined(overrides.browser),
+function mergeConfig(base: FullConfig, overrides: Config): FullConfig {
+  const browser: FullConfig['browser'] = {
+    browserName: overrides.browser?.browserName ?? base.browser?.browserName ?? 'chromium',
+    isolated: overrides.browser?.isolated ?? base.browser?.isolated ?? false,
     launchOptions: {
       ...pickDefined(base.browser?.launchOptions),
       ...pickDefined(overrides.browser?.launchOptions),
@@ -228,6 +250,9 @@ function mergeConfig(base: Config, overrides: Config): Config {
       ...pickDefined(base.browser?.contextOptions),
       ...pickDefined(overrides.browser?.contextOptions),
     },
+    userDataDir: overrides.browser?.userDataDir ?? base.browser?.userDataDir,
+    cdpEndpoint: overrides.browser?.cdpEndpoint ?? base.browser?.cdpEndpoint,
+    remoteEndpoint: overrides.browser?.remoteEndpoint ?? base.browser?.remoteEndpoint,
   };
 
   if (browser.browserName !== 'chromium' && browser.launchOptions)
@@ -240,6 +265,6 @@ function mergeConfig(base: Config, overrides: Config): Config {
     network: {
       ...pickDefined(base.network),
       ...pickDefined(overrides.network),
-    },
-  };
+    }
+  } as FullConfig;
 }

src/connection.ts

@@ -21,10 +21,10 @@ import { zodToJsonSchema } from 'zod-to-json-schema';
 import { Context, packageJSON } from './context.js';
 import { snapshotTools, visionTools } from './tools.js';
 
-import type { Config } from '../config.js';
 import type { Transport } from '@modelcontextprotocol/sdk/shared/transport.js';
+import { FullConfig } from './config.js';
 
-export async function createConnection(config: Config): Promise<Connection> {
+export async function createConnection(config: FullConfig): Promise<Connection> {
   const allTools = config.vision ? visionTools : snapshotTools;
   const tools = allTools.filter(tool => !config.capabilities || tool.capability === 'core' || config.capabilities.includes(tool.capability));
 

src/context.ts

@@ -21,14 +21,14 @@ import path from 'node:path';
 
 import * as playwright from 'playwright';
 
-import { waitForCompletion } from './tools/utils.js';
+import { callOnPageNoTrace, waitForCompletion } from './tools/utils.js';
 import { ManualPromise } from './manualPromise.js';
 import { Tab } from './tab.js';
+import { outputFile } from './config.js';
 
 import type { ImageContent, TextContent } from '@modelcontextprotocol/sdk/types.js';
 import type { ModalState, Tool, ToolActionResult } from './tools/tool.js';
-import type { Config } from '../config.js';
-import { outputFile } from './config.js';
+import type { FullConfig } from './config.js';
 
 type PendingAction = {
   dialogShown: ManualPromise<void>;
@@ -41,7 +41,7 @@ type BrowserContextAndBrowser = {
 
 export class Context {
   readonly tools: Tool[];
-  readonly config: Config;
+  readonly config: FullConfig;
   private _browserContextPromise: Promise<BrowserContextAndBrowser> | undefined;
   private _tabs: Tab[] = [];
   private _currentTab: Tab | undefined;
@@ -49,7 +49,7 @@ export class Context {
   private _pendingAction: PendingAction | undefined;
   private _downloads: { download: playwright.Download, finished: boolean, outputFile: string }[] = [];
 
-  constructor(tools: Tool[], config: Config) {
+  constructor(tools: Tool[], config: FullConfig) {
     this.tools = tools;
     this.config = config;
   }
@@ -112,7 +112,7 @@ export class Context {
     const lines: string[] = ['### Open tabs'];
     for (let i = 0; i < this._tabs.length; i++) {
       const tab = this._tabs[i];
-      const title = await tab.page.title();
+      const title = await tab.title();
       const url = tab.page.url();
       const current = tab === this._currentTab ? ' (current)' : '';
       lines.push(`- ${i + 1}:${current} [${title}] (${url})`);
@@ -149,7 +149,7 @@ export class Context {
     let actionResult: { content?: (ImageContent | TextContent)[] } | undefined;
     try {
       if (waitForNetwork)
-        actionResult = await waitForCompletion(this, tab.page, async () => racingAction?.()) ?? undefined;
+        actionResult = await waitForCompletion(this, tab, async () => racingAction?.()) ?? undefined;
       else
         actionResult = await racingAction?.() ?? undefined;
     } finally {
@@ -193,7 +193,7 @@ ${code.join('\n')}
 
     result.push(
         `- Page URL: ${tab.page.url()}`,
-        `- Page Title: ${await tab.page.title()}`
+        `- Page Title: ${await tab.title()}`
     );
 
     if (captureSnapshot && tab.hasSnapshot())
@@ -213,10 +213,14 @@ ${code.join('\n')}
   }
 
   async waitForTimeout(time: number) {
-    if (this._currentTab && !this._javaScriptBlocked())
-      await this._currentTab.page.evaluate(() => new Promise(f => setTimeout(f, 1000)));
-    else
+    if (!this._currentTab || this._javaScriptBlocked()) {
       await new Promise(f => setTimeout(f, time));
+      return;
+    }
+
+    await callOnPageNoTrace(this._currentTab.page, page => {
+      return page.evaluate(() => new Promise(f => setTimeout(f, 1000)));
+    });
   }
 
   private async _raceAgainstModalDialogs(action: () => Promise<ToolActionResult>): Promise<ToolActionResult> {
@@ -288,6 +292,8 @@ ${code.join('\n')}
     this._browserContextPromise = undefined;
 
     await promise.then(async ({ browserContext, browser }) => {
+      if (this.config.saveTrace)
+        await browserContext.tracing.stop();
       await browserContext.close().then(async () => {
         await browser?.close();
       }).catch(() => {});
@@ -324,6 +330,14 @@ ${code.join('\n')}
     for (const page of browserContext.pages())
       this._onPageCreated(page);
     browserContext.on('page', page => this._onPageCreated(page));
+    if (this.config.saveTrace) {
+      await browserContext.tracing.start({
+        name: 'trace',
+        screenshots: false,
+        snapshots: true,
+        sources: false,
+      });
+    }
     return { browser, browserContext };
   }
 
@@ -351,12 +365,12 @@ ${code.join('\n')}
   }
 }
 
-async function createIsolatedContext(browserConfig: Config['browser']): Promise<BrowserContextAndBrowser> {
+async function createIsolatedContext(browserConfig: FullConfig['browser']): Promise<BrowserContextAndBrowser> {
   try {
     const browserName = browserConfig?.browserName ?? 'chromium';
     const browserType = playwright[browserName];
-    const browser = await browserType.launch(browserConfig?.launchOptions);
-    const browserContext = await browser.newContext(browserConfig?.contextOptions);
+    const browser = await browserType.launch(browserConfig.launchOptions);
+    const browserContext = await browser.newContext(browserConfig.contextOptions);
     return { browser, browserContext };
   } catch (error: any) {
     if (error.message.includes('Executable doesn\'t exist'))
@@ -365,12 +379,12 @@ async function createIsolatedContext(browserConfig: Config['browser']): Promise<
   }
 }
 
-async function launchPersistentContext(browserConfig: Config['browser']): Promise<BrowserContextAndBrowser> {
+async function launchPersistentContext(browserConfig: FullConfig['browser']): Promise<BrowserContextAndBrowser> {
   try {
-    const browserName = browserConfig?.browserName ?? 'chromium';
-    const userDataDir = browserConfig?.userDataDir ?? await createUserDataDir({ ...browserConfig, browserName });
+    const browserName = browserConfig.browserName ?? 'chromium';
+    const userDataDir = browserConfig.userDataDir ?? await createUserDataDir({ ...browserConfig, browserName });
     const browserType = playwright[browserName];
-    const browserContext = await browserType.launchPersistentContext(userDataDir, { ...browserConfig?.launchOptions, ...browserConfig?.contextOptions });
+    const browserContext = await browserType.launchPersistentContext(userDataDir, { ...browserConfig.launchOptions, ...browserConfig.contextOptions });
     return { browserContext };
   } catch (error: any) {
     if (error.message.includes('Executable doesn\'t exist'))
@@ -379,7 +393,7 @@ async function launchPersistentContext(browserConfig: Config['browser']): Promis
   }
 }
 
-async function createUserDataDir(browserConfig: Config['browser']) {
+async function createUserDataDir(browserConfig: FullConfig['browser']) {
   let cacheDirectory: string;
   if (process.platform === 'linux')
     cacheDirectory = process.env.XDG_CACHE_HOME || path.join(os.homedir(), '.cache');
@@ -389,14 +403,10 @@ async function createUserDataDir(browserConfig: Config['browser']) {
     cacheDirectory = process.env.LOCALAPPDATA || path.join(os.homedir(), 'AppData', 'Local');
   else
     throw new Error('Unsupported platform: ' + process.platform);
-  const result = path.join(cacheDirectory, 'ms-playwright', `mcp-${browserConfig?.launchOptions?.channel ?? browserConfig?.browserName}-profile`);
+  const result = path.join(cacheDirectory, 'ms-playwright', `mcp-${browserConfig.launchOptions?.channel ?? browserConfig?.browserName}-profile`);
   await fs.promises.mkdir(result, { recursive: true });
   return result;
 }
 
-export async function generateLocator(locator: playwright.Locator): Promise<string> {
-  return (locator as any)._generateLocatorString();
-}
-
 const __filename = url.fileURLToPath(import.meta.url);
 export const packageJSON = JSON.parse(fs.readFileSync(path.join(path.dirname(__filename), '..', 'package.json'), 'utf8'));

src/index.ts

@@ -15,9 +15,11 @@
  */
 
 import { Connection, createConnection as createConnectionImpl } from './connection.js';
+import { resolveConfig } from './config.js';
 
 import type { Config } from '../config.js';
 
-export async function createConnection(config: Config = {}): Promise<Connection> {
+export async function createConnection(userConfig: Config = {}): Promise<Connection> {
+  const config = await resolveConfig(userConfig);
   return createConnectionImpl(config);
 }

src/pageSnapshot.ts

@@ -15,6 +15,11 @@
  */
 
 import * as playwright from 'playwright';
+import { callOnPageNoTrace } from './tools/utils.js';
+
+type PageEx = playwright.Page & {
+  _snapshotForAI: () => Promise<string>;
+};
 
 export class PageSnapshot {
   private _page: playwright.Page;
@@ -35,11 +40,14 @@ export class PageSnapshot {
   }
 
   private async _build() {
-    const yamlDocument = await (this._page as any)._snapshotForAI();
+    // FIXME: Rountrip evaluate to ensure _snapshotForAI works.
+    // This probably broke once we moved off locator snapshots
+    await this._page.evaluate(() => 1);
+    const snapshot = await callOnPageNoTrace(this._page, page => (page as PageEx)._snapshotForAI());
     this._text = [
       `- Page Snapshot`,
       '```yaml',
-      yamlDocument.toString({ indentSeq: false }).trim(),
+      snapshot,
       '```',
     ].join('\n');
   }

src/program.ts

@@ -17,7 +17,9 @@
 import { program } from 'commander';
 
 import { startHttpTransport, startStdioTransport } from './transport.js';
-import { resolveConfig } from './config.js';
+import { resolveCLIConfig } from './config.js';
+// @ts-ignore
+import { startTraceViewerServer } from 'playwright-core/lib/server';
 
 import type { Connection } from './connection.js';
 import { packageJSON } from './context.js';
@@ -44,13 +46,14 @@ program
     .option('--port <port>', 'port to listen on for SSE transport.')
     .option('--proxy-bypass <bypass>', 'comma-separated domains to bypass proxy, for example ".com,chromium.org,.domain.com"')
     .option('--proxy-server <proxy>', 'specify proxy server, for example "http://myproxy:3128" or "socks5://myproxy:8080"')
+    .option('--save-trace', 'Whether to save the Playwright Trace of the session into the output directory.')
     .option('--storage-state <path>', 'path to the storage state file for isolated sessions.')
     .option('--user-agent <ua string>', 'specify user agent string')
     .option('--user-data-dir <path>', 'path to the user data directory. If not specified, a temporary directory will be created.')
     .option('--viewport-size <size>', 'specify browser viewport size in pixels, for example "1280, 720"')
     .option('--vision', 'Run server that uses screenshots (Aria snapshots are used by default)')
     .action(async options => {
-      const config = await resolveConfig(options);
+      const config = await resolveCLIConfig(options);
       const connectionList: Connection[] = [];
       setupExitWatchdog(connectionList);
 
@@ -58,6 +61,14 @@ program
         startHttpTransport(config, +options.port, options.host, connectionList);
       else
         await startStdioTransport(config, connectionList);
+
+      if (config.saveTrace) {
+        const server = await startTraceViewerServer();
+        const urlPrefix = server.urlPrefix('human-readable');
+        const url = urlPrefix + '/trace/index.html?trace=' + config.browser.launchOptions.tracesDir + '/trace.json';
+        // eslint-disable-next-line no-console
+        console.error('\nTrace viewer listening on ' + url);
+      }
     });
 
 function setupExitWatchdog(connectionList: Connection[]) {

src/tab.ts

@@ -19,6 +19,7 @@ import * as playwright from 'playwright';
 import { PageSnapshot } from './pageSnapshot.js';
 
 import type { Context } from './context.js';
+import { callOnPageNoTrace } from './tools/utils.js';
 
 export class Tab {
   readonly context: Context;
@@ -61,10 +62,18 @@ export class Tab {
     this._onPageClose(this);
   }
 
+  async title(): Promise<string> {
+    return await callOnPageNoTrace(this.page, page => page.title());
+  }
+
+  async waitForLoadState(state: 'load', options?: { timeout?: number }): Promise<void> {
+    await callOnPageNoTrace(this.page, page => page.waitForLoadState(state, options).catch(() => {}));
+  }
+
   async navigate(url: string) {
     this._clearCollectedArtifacts();
 
-    const downloadEvent = this.page.waitForEvent('download').catch(() => {});
+    const downloadEvent = callOnPageNoTrace(this.page, page => page.waitForEvent('download').catch(() => {}));
     try {
       await this.page.goto(url, { waitUntil: 'domcontentloaded' });
     } catch (_e: unknown) {
@@ -85,7 +94,7 @@ export class Tab {
     }
 
     // Cap load event to 5 seconds, the page is operational at this point.
-    await this.page.waitForLoadState('load', { timeout: 5000 }).catch(() => {});
+    await this.waitForLoadState('load', { timeout: 5000 });
   }
 
   hasSnapshot(): boolean {

src/tools/utils.ts

@@ -16,8 +16,9 @@
 
 import type * as playwright from 'playwright';
 import type { Context } from '../context.js';
+import type { Tab } from '../tab.js';
 
-export async function waitForCompletion<R>(context: Context, page: playwright.Page, callback: () => Promise<R>): Promise<R> {
+export async function waitForCompletion<R>(context: Context, tab: Tab, callback: () => Promise<R>): Promise<R> {
   const requests = new Set<playwright.Request>();
   let frameNavigated = false;
   let waitCallback: () => void = () => {};
@@ -36,9 +37,7 @@ export async function waitForCompletion<R>(context: Context, page: playwright.Pa
     frameNavigated = true;
     dispose();
     clearTimeout(timeout);
-    void frame.waitForLoadState('load').then(() => {
-      waitCallback();
-    });
+    void tab.waitForLoadState('load').then(waitCallback);
   };
 
   const onTimeout = () => {
@@ -46,15 +45,15 @@ export async function waitForCompletion<R>(context: Context, page: playwright.Pa
     waitCallback();
   };
 
-  page.on('request', requestListener);
-  page.on('requestfinished', requestFinishedListener);
-  page.on('framenavigated', frameNavigateListener);
+  tab.page.on('request', requestListener);
+  tab.page.on('requestfinished', requestFinishedListener);
+  tab.page.on('framenavigated', frameNavigateListener);
   const timeout = setTimeout(onTimeout, 10000);
 
   const dispose = () => {
-    page.off('request', requestListener);
-    page.off('requestfinished', requestFinishedListener);
-    page.off('framenavigated', frameNavigateListener);
+    tab.page.off('request', requestListener);
+    tab.page.off('requestfinished', requestFinishedListener);
+    tab.page.off('framenavigated', frameNavigateListener);
     clearTimeout(timeout);
   };
 
@@ -79,5 +78,9 @@ export function sanitizeForFilePath(s: string) {
 }
 
 export async function generateLocator(locator: playwright.Locator): Promise<string> {
-  return (locator as any)._generateLocatorString();
+  return (locator as any)._frame._wrapApiCall(() => (locator as any)._generateLocatorString(), true);
+}
+
+export async function callOnPageNoTrace<T>(page: playwright.Page, callback: (page: playwright.Page) => Promise<T>): Promise<T> {
+  return await (page as any)._wrapApiCall(() => callback(page), true);
 }

src/transport.ts

@@ -24,16 +24,16 @@ import { StdioServerTransport } from '@modelcontextprotocol/sdk/server/stdio.js'
 
 import { createConnection } from './connection.js';
 
-import type { Config } from '../config.js';
 import type { Connection } from './connection.js';
+import type { FullConfig } from './config.js';
 
-export async function startStdioTransport(config: Config, connectionList: Connection[]) {
+export async function startStdioTransport(config: FullConfig, connectionList: Connection[]) {
   const connection = await createConnection(config);
   await connection.connect(new StdioServerTransport());
   connectionList.push(connection);
 }
 
-async function handleSSE(config: Config, req: http.IncomingMessage, res: http.ServerResponse, url: URL, sessions: Map<string, SSEServerTransport>, connectionList: Connection[]) {
+async function handleSSE(config: FullConfig, req: http.IncomingMessage, res: http.ServerResponse, url: URL, sessions: Map<string, SSEServerTransport>, connectionList: Connection[]) {
   if (req.method === 'POST') {
     const sessionId = url.searchParams.get('sessionId');
     if (!sessionId) {
@@ -68,7 +68,7 @@ async function handleSSE(config: Config, req: http.IncomingMessage, res: http.Se
   res.end('Method not allowed');
 }
 
-async function handleStreamable(config: Config, req: http.IncomingMessage, res: http.ServerResponse, sessions: Map<string, StreamableHTTPServerTransport>, connectionList: Connection[]) {
+async function handleStreamable(config: FullConfig, req: http.IncomingMessage, res: http.ServerResponse, sessions: Map<string, StreamableHTTPServerTransport>, connectionList: Connection[]) {
   const sessionId = req.headers['mcp-session-id'] as string | undefined;
   if (sessionId) {
     const transport = sessions.get(sessionId);
@@ -104,7 +104,7 @@ async function handleStreamable(config: Config, req: http.IncomingMessage, res:
   res.end('Invalid request');
 }
 
-export function startHttpTransport(config: Config, port: number, hostname: string | undefined, connectionList: Connection[]) {
+export function startHttpTransport(config: FullConfig, port: number, hostname: string | undefined, connectionList: Connection[]) {
   const sseSessions = new Map<string, SSEServerTransport>();
   const streamableSessions = new Map<string, StreamableHTTPServerTransport>();
   const httpServer = http.createServer(async (req, res) => {
@@ -140,6 +140,6 @@ export function startHttpTransport(config: Config, port: number, hostname: strin
       'If your client supports streamable HTTP, you can use the /mcp endpoint instead.',
     ].join('\n');
     // eslint-disable-next-line no-console
-    console.log(message);
+    console.error(message);
   });
 }

tests/cdp.spec.ts

@@ -16,16 +16,21 @@
 
 import { test, expect } from './fixtures.js';
 
-test('cdp server', async ({ cdpEndpoint, startClient, server }) => {
-  const client = await startClient({ args: [`--cdp-endpoint=${await cdpEndpoint()}`] });
+test('cdp server', async ({ cdpServer, startClient, server }) => {
+  await cdpServer.start();
+  const client = await startClient({ args: [`--cdp-endpoint=${cdpServer.endpoint}`] });
   expect(await client.callTool({
     name: 'browser_navigate',
     arguments: { url: server.HELLO_WORLD },
   })).toContainTextContent(`- generic [ref=e1]: Hello, world!`);
 });
 
-test('cdp server reuse tab', async ({ cdpEndpoint, startClient }) => {
-  const client = await startClient({ args: [`--cdp-endpoint=${await cdpEndpoint()}`] });
+test('cdp server reuse tab', async ({ cdpServer, startClient, server }) => {
+  const browserContext = await cdpServer.start();
+  const client = await startClient({ args: [`--cdp-endpoint=${cdpServer.endpoint}`] });
+
+  const [page] = browserContext.pages();
+  await page.goto(server.HELLO_WORLD);
 
   expect(await client.callTool({
     name: 'browser_click',
@@ -43,18 +48,17 @@ test('cdp server reuse tab', async ({ cdpEndpoint, startClient }) => {
 // <internal code to capture accessibility snapshot>
 \`\`\`
 
-- Page URL: data:text/html,hello world
-- Page Title: 
+- Page URL: ${server.HELLO_WORLD}
+- Page Title: Title
 - Page Snapshot
 \`\`\`yaml
-- generic [ref=e1]: hello world
+- generic [ref=e1]: Hello, world!
 \`\`\`
 `);
 });
 
-test('should throw connection error and allow re-connecting', async ({ cdpEndpoint, startClient, server }) => {
-  const port = 3200 + test.info().parallelIndex;
-  const client = await startClient({ args: [`--cdp-endpoint=http://localhost:${port}`] });
+test('should throw connection error and allow re-connecting', async ({ cdpServer, startClient, server }) => {
+  const client = await startClient({ args: [`--cdp-endpoint=${cdpServer.endpoint}`] });
 
   server.setContent('/', `
     <title>Title</title>
@@ -65,7 +69,7 @@ test('should throw connection error and allow re-connecting', async ({ cdpEndpoi
     name: 'browser_navigate',
     arguments: { url: server.PREFIX },
   })).toContainTextContent(`Error: browserType.connectOverCDP: connect ECONNREFUSED`);
-  await cdpEndpoint(port);
+  await cdpServer.start();
   expect(await client.callTool({
     name: 'browser_navigate',
     arguments: { url: server.PREFIX },

tests/files.spec.ts

@@ -126,7 +126,12 @@ test('clicking on download link emits download', async ({ startClient, localOutp
 - Downloaded file test.txt to ${path.join(outputDir, 'test.txt')}`);
 });
 
-test('navigating to download link emits download', async ({ client, server, mcpBrowser }) => {
+test('navigating to download link emits download', async ({ startClient, localOutputPath, mcpBrowser, server }) => {
+  const outputDir = localOutputPath('output');
+  const client = await startClient({
+    args: ['--output-dir', outputDir],
+  });
+
   test.skip(mcpBrowser === 'webkit' && process.platform === 'linux', 'https://github.com/microsoft/playwright/blob/8e08fdb52c27bb75de9bf87627bf740fadab2122/tests/library/download.spec.ts#L436');
   server.route('/download', (req, res) => {
     res.writeHead(200, {

tests/fixtures.ts

@@ -22,22 +22,27 @@ import { chromium } from 'playwright';
 import { test as baseTest, expect as baseExpect } from '@playwright/test';
 import { StdioClientTransport } from '@modelcontextprotocol/sdk/client/stdio.js';
 import { Client } from '@modelcontextprotocol/sdk/client/index.js';
-import { ChildProcessWithoutNullStreams, spawn } from 'child_process';
 import { TestServer } from './testserver/index.ts';
 
 import type { Config } from '../config';
+import type { BrowserContext } from 'playwright';
 
 export type TestOptions = {
   mcpBrowser: string | undefined;
   mcpMode: 'docker' | undefined;
 };
 
+type CDPServer = {
+  endpoint: string;
+  start: () => Promise<BrowserContext>;
+};
+
 type TestFixtures = {
   client: Client;
   visionClient: Client;
   startClient: (options?: { clientName?: string, args?: string[], config?: Config }) => Promise<Client>;
   wsEndpoint: string;
-  cdpEndpoint: (port?: number) => Promise<string>;
+  cdpServer: CDPServer;
   server: TestServer;
   httpsServer: TestServer;
   mcpHeadless: boolean;
@@ -95,39 +100,25 @@ export const test = baseTest.extend<TestFixtures & TestOptions, WorkerFixtures>(
     await browserServer.close();
   },
 
-  cdpEndpoint: async ({ }, use, testInfo) => {
-    let browserProcess: ChildProcessWithoutNullStreams | undefined;
+  cdpServer: async ({ mcpBrowser }, use, testInfo) => {
+    test.skip(!['chrome', 'msedge', 'chromium'].includes(mcpBrowser!), 'CDP is not supported for non-Chromium browsers');
 
-    await use(async port => {
-      if (!port)
-        port = 3200 + test.info().parallelIndex;
-      if (browserProcess)
-        return `http://localhost:${port}`;
-      browserProcess = spawn(chromium.executablePath(), [
-        `--user-data-dir=${testInfo.outputPath('user-data-dir')}`,
-        `--remote-debugging-port=${port}`,
-        `--no-first-run`,
-        `--no-sandbox`,
-        `--headless`,
-        '--use-mock-keychain',
-        `data:text/html,hello world`,
-      ], {
-        stdio: 'pipe',
-      });
-      await new Promise<void>(resolve => {
-        browserProcess!.stderr.on('data', data => {
-          if (data.toString().includes('DevTools listening on '))
-            resolve();
+    let browserContext: BrowserContext | undefined;
+    const port = 3200 + test.info().parallelIndex;
+    await use({
+      endpoint: `http://localhost:${port}`,
+      start: async () => {
+        browserContext = await chromium.launchPersistentContext(testInfo.outputPath('cdp-user-data-dir'), {
+          channel: mcpBrowser,
+          headless: true,
+          args: [
+            `--remote-debugging-port=${port}`,
+          ],
         });
-      });
-      return `http://localhost:${port}`;
-    });
-    await new Promise<void>(resolve => {
-      if (!browserProcess)
-        return resolve();
-      browserProcess.on('exit', () => resolve());
-      browserProcess.kill();
+        return browserContext;
+      }
     });
+    await browserContext?.close();
   },
 
   mcpHeadless: async ({ headless }, use) => {

tests/pdf.spec.ts

@@ -30,7 +30,12 @@ test('save as pdf unavailable', async ({ startClient, server }) => {
   })).toHaveTextContent(/Tool \"browser_pdf_save\" not found/);
 });
 
-test('save as pdf', async ({ client, mcpBrowser, server }) => {
+test('save as pdf', async ({ startClient, mcpBrowser, server, localOutputPath }) => {
+  const outputDir = localOutputPath('output');
+  const client = await startClient({
+    config: { outputDir },
+  });
+
   test.skip(!!mcpBrowser && !['chromium', 'chrome', 'msedge'].includes(mcpBrowser), 'Save as PDF is only supported in Chromium.');
 
   expect(await client.callTool({
@@ -73,6 +78,7 @@ test('save as pdf (filename: output.pdf)', async ({ startClient, mcpBrowser, ser
   const files = [...fs.readdirSync(outputDir)];
 
   expect(fs.existsSync(outputDir)).toBeTruthy();
-  expect(files).toHaveLength(1);
-  expect(files[0]).toMatch(/^output.pdf$/);
+  const pdfFiles = files.filter(f => f.endsWith('.pdf'));
+  expect(pdfFiles).toHaveLength(1);
+  expect(pdfFiles[0]).toMatch(/^output.pdf$/);
 });

tests/screenshot.spec.ts

@@ -18,7 +18,11 @@ import fs from 'fs';
 
 import { test, expect } from './fixtures.js';
 
-test('browser_take_screenshot (viewport)', async ({ client, server }) => {
+test('browser_take_screenshot (viewport)', async ({ startClient, server, localOutputPath }) => {
+  const outputDir = localOutputPath('output');
+  const client = await startClient({
+    args: ['--output-dir', outputDir],
+  });
   expect(await client.callTool({
     name: 'browser_navigate',
     arguments: { url: server.HELLO_WORLD },
@@ -41,7 +45,11 @@ test('browser_take_screenshot (viewport)', async ({ client, server }) => {
   });
 });
 
-test('browser_take_screenshot (element)', async ({ client, server }) => {
+test('browser_take_screenshot (element)', async ({ startClient, server, localOutputPath }) => {
+  const outputDir = localOutputPath('output');
+  const client = await startClient({
+    args: ['--output-dir', outputDir],
+  });
   expect(await client.callTool({
     name: 'browser_navigate',
     arguments: { url: server.HELLO_WORLD },
@@ -83,7 +91,9 @@ test('--output-dir should work', async ({ startClient, localOutputPath, server }
   });
 
   expect(fs.existsSync(outputDir)).toBeTruthy();
-  expect([...fs.readdirSync(outputDir)]).toHaveLength(1);
+  const files = [...fs.readdirSync(outputDir)].filter(f => f.endsWith('.jpeg'));
+  expect(files).toHaveLength(1);
+  expect(files[0]).toMatch(/^page-\d{4}-\d{2}-\d{2}T\d{2}-\d{2}-\d{2}-\d{3}Z\.jpeg$/);
 });
 
 for (const raw of [undefined, true]) {
@@ -117,7 +127,7 @@ for (const raw of [undefined, true]) {
       ],
     });
 
-    const files = [...fs.readdirSync(outputDir)];
+    const files = [...fs.readdirSync(outputDir)].filter(f => f.endsWith(`.${ext}`));
 
     expect(fs.existsSync(outputDir)).toBeTruthy();
     expect(files).toHaveLength(1);
@@ -157,16 +167,17 @@ test('browser_take_screenshot (filename: "output.jpeg")', async ({ startClient,
     ],
   });
 
-  const files = [...fs.readdirSync(outputDir)];
+  const files = [...fs.readdirSync(outputDir)].filter(f => f.endsWith('.jpeg'));
 
   expect(fs.existsSync(outputDir)).toBeTruthy();
   expect(files).toHaveLength(1);
-  expect(files[0]).toMatch(/^output.jpeg$/);
+  expect(files[0]).toMatch(/^output\.jpeg$/);
 });
 
-test('browser_take_screenshot (noImageResponses)', async ({ startClient, server }) => {
+test('browser_take_screenshot (noImageResponses)', async ({ startClient, server, localOutputPath }) => {
   const client = await startClient({
     config: {
+      outputDir: localOutputPath('output'),
       noImageResponses: true,
     },
   });
@@ -192,8 +203,12 @@ test('browser_take_screenshot (noImageResponses)', async ({ startClient, server
   });
 });
 
-test('browser_take_screenshot (cursor)', async ({ startClient, server }) => {
-  const client = await startClient({ clientName: 'cursor:vscode' });
+test('browser_take_screenshot (cursor)', async ({ startClient, server, localOutputPath }) => {
+  const outputDir = localOutputPath('output');
+  const client = await startClient({
+    clientName: 'cursor:vscode',
+    config: { outputDir },
+  });
 
   expect(await client.callTool({
     name: 'browser_navigate',

tests/sse.spec.ts

@@ -35,10 +35,10 @@ const test = baseTest.extend<{ serverEndpoint: string }>({
   serverEndpoint: async ({}, use) => {
     const cp = spawn('node', [path.join(path.dirname(__filename), '../cli.js'), '--port', '0'], { stdio: 'pipe' });
     try {
-      let stdout = '';
-      const url = await new Promise<string>(resolve => cp.stdout?.on('data', data => {
-        stdout += data.toString();
-        const match = stdout.match(/Listening on (http:\/\/.*)/);
+      let stderr = '';
+      const url = await new Promise<string>(resolve => cp.stderr?.on('data', data => {
+        stderr += data.toString();
+        const match = stderr.match(/Listening on (http:\/\/.*)/);
         if (match)
           resolve(match[1]);
       }));
@@ -65,11 +65,17 @@ test('streamable http transport', async ({ serverEndpoint }) => {
   expect(transport.sessionId, 'has session support').toBeDefined();
 });
 
-test('sse transport via public API', async ({ server }) => {
+test('sse transport via public API', async ({ server, localOutputPath }) => {
+  const userDataDir = localOutputPath('user-data-dir');
   const sessions = new Map<string, SSEServerTransport>();
   const mcpServer = http.createServer(async (req, res) => {
     if (req.method === 'GET') {
-      const connection = await createConnection({ browser: { launchOptions: { headless: true } } });
+      const connection = await createConnection({
+        browser: {
+          userDataDir,
+          launchOptions: { headless: true }
+        },
+      });
       const transport = new SSEServerTransport('/sse', res);
       sessions.set(transport.sessionId, transport);
       await connection.connect(transport);

tests/tabs.spec.ts

@@ -14,8 +14,6 @@
  * limitations under the License.
  */
 
-import { chromium } from 'playwright';
-
 import { test, expect } from './fixtures.js';
 
 import type { Client } from '@modelcontextprotocol/sdk/client/index.js';
@@ -139,17 +137,14 @@ test('close tab', async ({ client }) => {
 \`\`\``);
 });
 
-test('reuse first tab when navigating', async ({ startClient, cdpEndpoint, server }) => {
-  server.setContent('/', `<title>Title</title><body>Body</body>`, 'text/html');
+test('reuse first tab when navigating', async ({ startClient, cdpServer, server }) => {
+  const browserContext = await cdpServer.start();
+  const pages = browserContext.pages();
 
-  const browser = await chromium.connectOverCDP(await cdpEndpoint());
-  const [context] = browser.contexts();
-  const pages = context.pages();
-
-  const client = await startClient({ args: [`--cdp-endpoint=${await cdpEndpoint()}`] });
+  const client = await startClient({ args: [`--cdp-endpoint=${cdpServer.endpoint}`] });
   await client.callTool({
     name: 'browser_navigate',
-    arguments: { url: server.PREFIX },
+    arguments: { url: server.HELLO_WORLD },
   });
 
   expect(pages.length).toBe(1);

tests/trace.spec.ts

@@ -0,0 +1,34 @@
+/**
+ * Copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import fs from 'fs';
+import path from 'path';
+
+import { test, expect } from './fixtures.js';
+
+test('check that trace is saved', async ({ startClient, server, localOutputPath }) => {
+  const outputDir = localOutputPath('output');
+  const client = await startClient({
+    args: ['--save-trace', `--output-dir=${outputDir}`],
+  });
+
+  expect(await client.callTool({
+    name: 'browser_navigate',
+    arguments: { url: server.HELLO_WORLD },
+  })).toContainTextContent(`Navigate to http://localhost`);
+
+  expect(fs.existsSync(path.join(outputDir, 'traces', 'trace.trace'))).toBeTruthy();
+});