chore: do not wrap mcp in proxy by default, drive-by deps fix (microsoft#909)

Author: pavelfeldman

src/browserContextFactory.ts

@@ -42,27 +42,23 @@ export function contextFactory(config: FullConfig): BrowserContextFactory {
 export type ClientInfo = { name?: string, version?: string, rootPath?: string };
 
 export interface BrowserContextFactory {
-  readonly name: string;
-  readonly description: string;
   createContext(clientInfo: ClientInfo, abortSignal: AbortSignal): Promise<{ browserContext: playwright.BrowserContext, close: () => Promise<void> }>;
 }
 
 class BaseContextFactory implements BrowserContextFactory {
-  readonly name: string;
-  readonly description: string;
   readonly config: FullConfig;
+  private _logName: string;
   protected _browserPromise: Promise<playwright.Browser> | undefined;
 
-  constructor(name: string, description: string, config: FullConfig) {
-    this.name = name;
-    this.description = description;
+  constructor(name: string, config: FullConfig) {
+    this._logName = name;
     this.config = config;
   }
 
   protected async _obtainBrowser(clientInfo: ClientInfo): Promise<playwright.Browser> {
     if (this._browserPromise)
       return this._browserPromise;
-    testDebug(`obtain browser (${this.name})`);
+    testDebug(`obtain browser (${this._logName})`);
     this._browserPromise = this._doObtainBrowser(clientInfo);
     void this._browserPromise.then(browser => {
       browser.on('disconnected', () => {
@@ -79,7 +75,7 @@ class BaseContextFactory implements BrowserContextFactory {
   }
 
   async createContext(clientInfo: ClientInfo): Promise<{ browserContext: playwright.BrowserContext, close: () => Promise<void> }> {
-    testDebug(`create browser context (${this.name})`);
+    testDebug(`create browser context (${this._logName})`);
     const browser = await this._obtainBrowser(clientInfo);
     const browserContext = await this._doCreateContext(browser);
     return { browserContext, close: () => this._closeBrowserContext(browserContext, browser) };
@@ -90,20 +86,20 @@ class BaseContextFactory implements BrowserContextFactory {
   }
 
   private async _closeBrowserContext(browserContext: playwright.BrowserContext, browser: playwright.Browser) {
-    testDebug(`close browser context (${this.name})`);
+    testDebug(`close browser context (${this._logName})`);
     if (browser.contexts().length === 1)
       this._browserPromise = undefined;
     await browserContext.close().catch(logUnhandledError);
     if (browser.contexts().length === 0) {
-      testDebug(`close browser (${this.name})`);
+      testDebug(`close browser (${this._logName})`);
       await browser.close().catch(logUnhandledError);
     }
   }
 }
 
 class IsolatedContextFactory extends BaseContextFactory {
   constructor(config: FullConfig) {
-    super('isolated', 'Create a new isolated browser context', config);
+    super('isolated', config);
   }
 
   protected override async _doObtainBrowser(clientInfo: ClientInfo): Promise<playwright.Browser> {
@@ -128,7 +124,7 @@ class IsolatedContextFactory extends BaseContextFactory {
 
 class CdpContextFactory extends BaseContextFactory {
   constructor(config: FullConfig) {
-    super('cdp', 'Connect to a browser over CDP', config);
+    super('cdp', config);
   }
 
   protected override async _doObtainBrowser(): Promise<playwright.Browser> {
@@ -142,7 +138,7 @@ class CdpContextFactory extends BaseContextFactory {
 
 class RemoteContextFactory extends BaseContextFactory {
   constructor(config: FullConfig) {
-    super('remote', 'Connect to a browser using a remote endpoint', config);
+    super('remote', config);
   }
 
   protected override async _doObtainBrowser(): Promise<playwright.Browser> {

src/browserServerBackend.ts

@@ -21,7 +21,6 @@ import { logUnhandledError } from './utils/log.js';
 import { Response } from './response.js';
 import { SessionLog } from './sessionLog.js';
 import { filteredTools } from './tools.js';
-import { packageJSON } from './utils/package.js';
 import { toMcpTool } from './mcp/tool.js';
 
 import type { Tool } from './tools/tool.js';
@@ -30,9 +29,6 @@ import type * as mcpServer from './mcp/server.js';
 import type { ServerBackend } from './mcp/server.js';
 
 export class BrowserServerBackend implements ServerBackend {
-  name = 'Playwright';
-  version = packageJSON.version;
-
   private _tools: Tool[];
   private _context: Context | undefined;
   private _sessionLog: SessionLog | undefined;

src/extension/cdpRelay.ts

@@ -26,7 +26,7 @@ import { spawn } from 'child_process';
 import http from 'http';
 import debug from 'debug';
 import { WebSocket, WebSocketServer } from 'ws';
-import { httpAddressToString } from '../utils/httpServer.js';
+import { httpAddressToString } from '../mcp/http.js';
 import { logUnhandledError } from '../utils/log.js';
 import { ManualPromise } from '../utils/manualPromise.js';
 import type websocket from 'ws';

src/extension/extensionContextFactory.ts

@@ -16,17 +16,14 @@
 
 import debug from 'debug';
 import * as playwright from 'playwright';
-import { startHttpServer } from '../utils/httpServer.js';
+import { startHttpServer } from '../mcp/http.js';
 import { CDPRelayServer } from './cdpRelay.js';
 
 import type { BrowserContextFactory, ClientInfo } from '../browserContextFactory.js';
 
 const debugLogger = debug('pw:mcp:relay');
 
 export class ExtensionContextFactory implements BrowserContextFactory {
-  name = 'extension';
-  description = 'Connect to a browser using the Playwright MCP extension';
-
   private _browserChannel: string;
   private _userDataDir?: string;
 

src/index.ts

@@ -18,6 +18,7 @@ import { BrowserServerBackend } from './browserServerBackend.js';
 import { resolveConfig } from './config.js';
 import { contextFactory } from './browserContextFactory.js';
 import * as mcpServer from './mcp/server.js';
+import { packageJSON } from './utils/package.js';
 
 import type { Config } from '../config.js';
 import type { BrowserContext } from 'playwright';
@@ -27,7 +28,7 @@ import type { Server } from '@modelcontextprotocol/sdk/server/index.js';
 export async function createConnection(userConfig: Config = {}, contextGetter?: () => Promise<BrowserContext>): Promise<Server> {
   const config = await resolveConfig(userConfig);
   const factory = contextGetter ? new SimpleBrowserContextFactory(contextGetter) : contextFactory(config);
-  return mcpServer.createServer(new BrowserServerBackend(config, factory), false);
+  return mcpServer.createServer('Playwright', packageJSON.version, new BrowserServerBackend(config, factory), false);
 }
 
 class SimpleBrowserContextFactory implements BrowserContextFactory {

src/loopTools/context.ts

@@ -23,6 +23,7 @@ import { OpenAIDelegate } from '../loop/loopOpenAI.js';
 import { ClaudeDelegate } from '../loop/loopClaude.js';
 import { InProcessTransport } from '../mcp/inProcessTransport.js';
 import * as mcpServer from '../mcp/server.js';
+import { packageJSON } from '../utils/package.js';
 
 import type { LLMDelegate } from '../loop/loop.js';
 import type { FullConfig } from '../config.js';
@@ -44,9 +45,9 @@ export class Context {
   }
 
   static async create(config: FullConfig) {
-    const client = new Client({ name: 'Playwright Proxy', version: '1.0.0' });
+    const client = new Client({ name: 'Playwright Proxy', version: packageJSON.version });
     const browserContextFactory = contextFactory(config);
-    const server = mcpServer.createServer(new BrowserServerBackend(config, browserContextFactory), false);
+    const server = mcpServer.createServer('Playwright Subagent', packageJSON.version, new BrowserServerBackend(config, browserContextFactory), false);
     await client.connect(new InProcessTransport(server));
     await client.ping();
     return new Context(config, client);

src/loopTools/main.ts

@@ -17,7 +17,6 @@
 import dotenv from 'dotenv';
 
 import * as mcpServer from '../mcp/server.js';
-import * as mcpTransport from '../mcp/transport.js';
 import { packageJSON } from '../utils/package.js';
 import { Context } from './context.js';
 import { perform } from './perform.js';
@@ -30,13 +29,16 @@ import type { Tool } from './tool.js';
 
 export async function runLoopTools(config: FullConfig) {
   dotenv.config();
-  const serverBackendFactory = () => new LoopToolsServerBackend(config);
-  await mcpTransport.start(serverBackendFactory, config.server);
+  const serverBackendFactory = {
+    name: 'Playwright',
+    nameInConfig: 'playwright-loop',
+    version: packageJSON.version,
+    create: () => new LoopToolsServerBackend(config)
+  };
+  await mcpServer.start(serverBackendFactory, config.server);
 }
 
 class LoopToolsServerBackend implements ServerBackend {
-  readonly name = 'Playwright';
-  readonly version = packageJSON.version;
   private _config: FullConfig;
   private _context: Context | undefined;
   private _tools: Tool<any>[] = [perform, snapshot];

src/mcp/DEPS.list

@@ -1,2 +1 @@
 [*]
-../utils/

src/mcp/README.md

@@ -1 +1 @@
-- Generic MCP utils, no dependencies on Playwright here.
+- Generic MCP utils, no dependencies on anything.

src/mcp/transport.ts renamed to src/mcp/http.ts

@@ -14,32 +14,60 @@
  * limitations under the License.
  */
 
+import assert from 'assert';
+import net from 'net';
 import http from 'http';
 import crypto from 'crypto';
+
 import debug from 'debug';
 
 import { SSEServerTransport } from '@modelcontextprotocol/sdk/server/sse.js';
 import { StreamableHTTPServerTransport } from '@modelcontextprotocol/sdk/server/streamableHttp.js';
-import { StdioServerTransport } from '@modelcontextprotocol/sdk/server/stdio.js';
-import { httpAddressToString, startHttpServer } from '../utils/httpServer.js';
 import * as mcpServer from './server.js';
 
 import type { ServerBackendFactory } from './server.js';
 
-export async function start(serverBackendFactory: ServerBackendFactory, options: { host?: string; port?: number }) {
-  if (options.port !== undefined) {
-    const httpServer = await startHttpServer(options);
-    startHttpTransport(httpServer, serverBackendFactory);
-  } else {
-    await startStdioTransport(serverBackendFactory);
-  }
+const testDebug = debug('pw:mcp:test');
+
+export async function startHttpServer(config: { host?: string, port?: number }, abortSignal?: AbortSignal): Promise<http.Server> {
+  const { host, port } = config;
+  const httpServer = http.createServer();
+  await new Promise<void>((resolve, reject) => {
+    httpServer.on('error', reject);
+    abortSignal?.addEventListener('abort', () => {
+      httpServer.close();
+      reject(new Error('Aborted'));
+    });
+    httpServer.listen(port, host, () => {
+      resolve();
+      httpServer.removeListener('error', reject);
+    });
+  });
+  return httpServer;
 }
 
-async function startStdioTransport(serverBackendFactory: ServerBackendFactory) {
-  await mcpServer.connect(serverBackendFactory, new StdioServerTransport(), false);
+export function httpAddressToString(address: string | net.AddressInfo | null): string {
+  assert(address, 'Could not bind server socket');
+  if (typeof address === 'string')
+    return address;
+  const resolvedPort = address.port;
+  let resolvedHost = address.family === 'IPv4' ? address.address : `[${address.address}]`;
+  if (resolvedHost === '0.0.0.0' || resolvedHost === '[::]')
+    resolvedHost = 'localhost';
+  return `http://${resolvedHost}:${resolvedPort}`;
 }
 
-const testDebug = debug('pw:mcp:test');
+export async function installHttpTransport(httpServer: http.Server, serverBackendFactory: ServerBackendFactory) {
+  const sseSessions = new Map();
+  const streamableSessions = new Map();
+  httpServer.on('request', async (req, res) => {
+    const url = new URL(`http://localhost${req.url}`);
+    if (url.pathname.startsWith('/sse'))
+      await handleSSE(serverBackendFactory, req, res, url, sseSessions);
+    else
+      await handleStreamable(serverBackendFactory, req, res, streamableSessions);
+  });
+}
 
 async function handleSSE(serverBackendFactory: ServerBackendFactory, req: http.IncomingMessage, res: http.ServerResponse, url: URL, sessions: Map<string, SSEServerTransport>) {
   if (req.method === 'POST') {
@@ -108,30 +136,3 @@ async function handleStreamable(serverBackendFactory: ServerBackendFactory, req:
   res.statusCode = 400;
   res.end('Invalid request');
 }
-
-function startHttpTransport(httpServer: http.Server, serverBackendFactory: ServerBackendFactory) {
-  const sseSessions = new Map();
-  const streamableSessions = new Map();
-  httpServer.on('request', async (req, res) => {
-    const url = new URL(`http://localhost${req.url}`);
-    if (url.pathname.startsWith('/sse'))
-      await handleSSE(serverBackendFactory, req, res, url, sseSessions);
-    else
-      await handleStreamable(serverBackendFactory, req, res, streamableSessions);
-  });
-  const url = httpAddressToString(httpServer.address());
-  const message = [
-    `Listening on ${url}`,
-    'Put this in your client config:',
-    JSON.stringify({
-      'mcpServers': {
-        'playwright': {
-          'url': `${url}/mcp`
-        }
-      }
-    }, undefined, 2),
-    'For legacy SSE transport support, you can use the /sse endpoint instead.',
-  ].join('\n');
-    // eslint-disable-next-line no-console
-  console.error(message);
-}