fix(mcp): use single output dir (#37436)

Author: pavelfeldman

packages/playwright/src/mcp/browser/browserContextFactory.ts

@@ -24,10 +24,12 @@ import { registryDirectory } from 'playwright-core/lib/server/registry/index';
 import { startTraceViewerServer } from 'playwright-core/lib/server';
 import { findBrowserProcess, getBrowserExecPath } from './processUtils';
 import { logUnhandledError, testDebug } from '../log';
-import { outputFile  } from './config';
+import { outputFile } from './config';
+import { firstRootPath } from '../sdk/server';
 
 import type { FullConfig } from './config';
 import type { LaunchOptions } from '../../../../playwright-core/src/client/types';
+import type { ClientInfo } from '../sdk/server';
 
 export function contextFactory(config: FullConfig): BrowserContextFactory {
   if (config.browser.remoteEndpoint)
@@ -39,8 +41,6 @@ export function contextFactory(config: FullConfig): BrowserContextFactory {
   return new PersistentContextFactory(config);
 }
 
-export type ClientInfo = { name?: string, version?: string, rootPath?: string };
-
 export interface BrowserContextFactory {
   createContext(clientInfo: ClientInfo, abortSignal: AbortSignal, toolName: string | undefined): Promise<{ browserContext: playwright.BrowserContext, close: () => Promise<void> }>;
 }
@@ -105,7 +105,7 @@ class IsolatedContextFactory extends BaseContextFactory {
   protected override async _doObtainBrowser(clientInfo: ClientInfo): Promise<playwright.Browser> {
     await injectCdpPort(this.config.browser);
     const browserType = playwright[this.config.browser.browserName];
-    const tracesDir = await outputFile(this.config, clientInfo.rootPath, `traces`);
+    const tracesDir = await outputFile(this.config, clientInfo, `traces`);
     if (this.config.saveTrace)
       await startTraceServer(this.config, tracesDir);
     return browserType.launch({
@@ -171,8 +171,8 @@ class PersistentContextFactory implements BrowserContextFactory {
   async createContext(clientInfo: ClientInfo): Promise<{ browserContext: playwright.BrowserContext, close: () => Promise<void> }> {
     await injectCdpPort(this.config.browser);
     testDebug('create browser context (persistent)');
-    const userDataDir = this.config.browser.userDataDir ?? await this._createUserDataDir(clientInfo.rootPath);
-    const tracesDir = await outputFile(this.config, clientInfo.rootPath, `traces`);
+    const userDataDir = this.config.browser.userDataDir ?? await this._createUserDataDir(clientInfo);
+    const tracesDir = await outputFile(this.config, clientInfo, `traces`);
     if (this.config.saveTrace)
       await startTraceServer(this.config, tracesDir);
 
@@ -218,10 +218,11 @@ class PersistentContextFactory implements BrowserContextFactory {
     testDebug('close browser context complete (persistent)');
   }
 
-  private async _createUserDataDir(rootPath: string | undefined) {
+  private async _createUserDataDir(clientInfo: ClientInfo) {
     const dir = process.env.PWMCP_PROFILES_DIR_FOR_TEST ?? registryDirectory;
     const browserToken = this.config.browser.launchOptions?.channel ?? this.config.browser?.browserName;
     // Hesitant putting hundreds of files into the user's workspace, so using it for hashing instead.
+    const rootPath = firstRootPath(clientInfo);
     const rootPathToken = rootPath ? `-${createHash(rootPath)}` : '';
     const result = path.join(dir, `mcp-${browserToken}${rootPathToken}`);
     await fs.promises.mkdir(result, { recursive: true });

packages/playwright/src/mcp/browser/browserServerBackend.ts

@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-import { fileURLToPath } from 'url';
 import { FullConfig } from './config';
 import { Context } from './context';
 import { logUnhandledError } from '../log';
@@ -41,19 +40,13 @@ export class BrowserServerBackend implements ServerBackend {
     this._tools = filteredTools(config);
   }
 
-  async initialize(server: mcpServer.Server, clientVersion: mcpServer.ClientVersion, roots: mcpServer.Root[]): Promise<void> {
-    let rootPath: string | undefined;
-    if (roots.length > 0) {
-      const firstRootUri = roots[0]?.uri;
-      const url = firstRootUri ? new URL(firstRootUri) : undefined;
-      rootPath = url ? fileURLToPath(url) : undefined;
-    }
-    this._sessionLog = this._config.saveSession ? await SessionLog.create(this._config, rootPath) : undefined;
+  async initialize(server: mcpServer.Server, clientInfo: mcpServer.ClientInfo): Promise<void> {
+    this._sessionLog = this._config.saveSession ? await SessionLog.create(this._config, clientInfo) : undefined;
     this._context = new Context({
       config: this._config,
       browserContextFactory: this._browserContextFactory,
       sessionLog: this._sessionLog,
-      clientInfo: { ...clientVersion, rootPath },
+      clientInfo,
     });
   }
 

packages/playwright/src/mcp/browser/config.ts

@@ -17,11 +17,15 @@
 import fs from 'fs';
 import os from 'os';
 import path from 'path';
+
 import { devices } from 'playwright-core';
 import { dotenv } from 'playwright-core/lib/utilsBundle';
 
+import { firstRootPath } from '../sdk/server';
+
 import type * as playwright from '../../../types/test';
 import type { Config, ToolCapability } from '../config';
+import type { ClientInfo } from '../sdk/server';
 
 export type CLIOptions = {
   allowedOrigins?: string[];
@@ -265,10 +269,11 @@ async function loadConfig(configFile: string | undefined): Promise<Config> {
   }
 }
 
-export async function outputFile(config: FullConfig, rootPath: string | undefined, name: string): Promise<string> {
+export async function outputFile(config: FullConfig, clientInfo: ClientInfo, name: string): Promise<string> {
+  const rootPath = firstRootPath(clientInfo);
   const outputDir = config.outputDir
     ?? (rootPath ? path.join(rootPath, '.playwright-mcp') : undefined)
-    ?? path.join(os.tmpdir(), 'playwright-mcp-output', sanitizeForFilePath(new Date().toISOString()));
+    ?? path.join(process.env.PW_TMPDIR_FOR_TEST ?? os.tmpdir(), 'playwright-mcp-output', String(clientInfo.timestamp));
 
   await fs.promises.mkdir(outputDir, { recursive: true });
   const fileName = sanitizeForFilePath(name);

packages/playwright/src/mcp/browser/context.ts

@@ -23,10 +23,11 @@ import * as codegen from './codegen';
 
 import type * as playwright from '../../../types/test';
 import type { FullConfig } from './config';
-import type { BrowserContextFactory, ClientInfo } from './browserContextFactory';
+import type { BrowserContextFactory } from './browserContextFactory';
 import type * as actions from './actions';
 import type { SessionLog } from './sessionLog';
 import type { Tracing } from '../../../../playwright-core/src/client/tracing';
+import type { ClientInfo } from '../sdk/server';
 
 const testDebug = debug('pw:mcp:test');
 
@@ -113,7 +114,7 @@ export class Context {
   }
 
   async outputFile(name: string): Promise<string> {
-    return outputFile(this.config, this._clientInfo.rootPath, name);
+    return outputFile(this.config, this._clientInfo, name);
   }
 
   private _onPageCreated(page: playwright.Page) {

packages/playwright/src/mcp/browser/sessionLog.ts

@@ -24,6 +24,7 @@ import { outputFile  } from './config';
 import type { FullConfig } from './config';
 import type * as actions from './actions';
 import type { Tab, TabSnapshot } from './tab';
+import type * as mcpServer from '../sdk/server';
 
 type LogEntry = {
   timestamp: number;
@@ -51,8 +52,8 @@ export class SessionLog {
     this._file = path.join(this._folder, 'session.md');
   }
 
-  static async create(config: FullConfig, rootPath: string | undefined): Promise<SessionLog> {
-    const sessionFolder = await outputFile(config, rootPath, `session-${Date.now()}`);
+  static async create(config: FullConfig, clientInfo: mcpServer.ClientInfo): Promise<SessionLog> {
+    const sessionFolder = await outputFile(config, clientInfo, `session-${Date.now()}`);
     await fs.promises.mkdir(sessionFolder, { recursive: true });
     // eslint-disable-next-line no-console
     console.error(`Session: ${sessionFolder}`);

packages/playwright/src/mcp/extension/cdpRelay.ts

@@ -34,7 +34,7 @@ import { logUnhandledError } from '../log';
 import * as protocol from './protocol';
 
 import type websocket from 'ws';
-import type { ClientInfo } from '../browser/browserContextFactory';
+import type { ClientInfo } from '../sdk/server';
 import type { ExtensionCommand, ExtensionEvents } from './protocol';
 import type { WebSocket, WebSocketServer } from 'playwright-core/lib/utilsBundle';
 

packages/playwright/src/mcp/extension/extensionContextFactory.ts

@@ -20,7 +20,8 @@ import { debug } from 'playwright-core/lib/utilsBundle';
 import { startHttpServer } from '../sdk/http';
 import { CDPRelayServer } from './cdpRelay';
 
-import type { BrowserContextFactory, ClientInfo } from '../browser/browserContextFactory';
+import type { BrowserContextFactory } from '../browser/browserContextFactory';
+import type { ClientInfo } from '../sdk/server';
 
 const debugLogger = debug('pw:mcp:relay');
 

packages/playwright/src/mcp/sdk/mdb.ts

@@ -34,15 +34,15 @@ export class MDBBackend implements mcpServer.ServerBackend {
   private _stack: { client: Client, toolNames: string[], resultPromise: ManualPromise<mcpServer.CallToolResult> | undefined }[] = [];
   private _interruptPromise: ManualPromise<mcpServer.CallToolResult> | undefined;
   private _topLevelBackend: mcpServer.ServerBackend;
-  private _roots: mcpServer.Root[] | undefined;
+  private _clientInfo: mcpServer.ClientInfo | undefined;
 
   constructor(topLevelBackend: mcpServer.ServerBackend) {
     this._topLevelBackend = topLevelBackend;
   }
 
-  async initialize(server: mcpServer.Server, clientVersion: mcpServer.ClientVersion, roots: mcpServer.Root[]): Promise<void> {
-    if (!this._roots)
-      this._roots = roots;
+  async initialize(server: mcpServer.Server, clientInfo: mcpServer.ClientInfo): Promise<void> {
+    if (!this._clientInfo)
+      this._clientInfo = clientInfo;
   }
 
   async listTools(): Promise<mcpServer.Tool[]> {
@@ -107,8 +107,8 @@ export class MDBBackend implements mcpServer.ServerBackend {
 
   private async _pushClient(transport: Transport, introMessage?: string): Promise<mcpServer.CallToolResult> {
     mdbDebug('pushing client to the stack');
-    const client = new mcpBundle.Client({ name: 'Internal client', version: '0.0.0' }, { capabilities: { roots: {} } });
-    client.setRequestHandler(mcpBundle.ListRootsRequestSchema, () => ({ roots: this._roots || [] }));
+    const client = new mcpBundle.Client({ name: 'Pushing client', version: '0.0.0' }, { capabilities: { roots: {} } });
+    client.setRequestHandler(mcpBundle.ListRootsRequestSchema, () => ({ roots: this._clientInfo?.roots || [] }));
     client.setRequestHandler(mcpBundle.PingRequestSchema, () => ({}));
     await client.connect(transport);
     mdbDebug('connected to the new client');
@@ -169,7 +169,7 @@ export async function runOnPauseBackendLoop(backend: mcpServer.ServerBackend, in
   await mcpHttp.installHttpTransport(httpServer, factory);
   const url = mcpHttp.httpAddressToString(httpServer.address());
 
-  const client = new mcpBundle.Client({ name: 'Internal client', version: '0.0.0' });
+  const client = new mcpBundle.Client({ name: 'On-pause client', version: '0.0.0' });
   client.setRequestHandler(mcpBundle.PingRequestSchema, () => ({}));
   const transport = new mcpBundle.StreamableHTTPClientTransport(new URL(process.env.PLAYWRIGHT_DEBUGGER_MCP!));
   await client.connect(transport);
@@ -205,8 +205,8 @@ class ServerBackendWithCloseListener implements mcpServer.ServerBackend {
     this._backend = backend;
   }
 
-  async initialize(server: mcpServer.Server, clientVersion: mcpServer.ClientVersion, roots: mcpServer.Root[]): Promise<void> {
-    await this._backend.initialize?.(server, clientVersion, roots);
+  async initialize(server: mcpServer.Server, clientInfo: mcpServer.ClientInfo): Promise<void> {
+    await this._backend.initialize?.(server, clientInfo);
   }
 
   async listTools(): Promise<mcpServer.Tool[]> {

packages/playwright/src/mcp/sdk/proxyBackend.ts

@@ -18,7 +18,7 @@ import { debug } from 'playwright-core/lib/utilsBundle';
 
 import * as mcpBundle from './bundle';
 
-import type { ServerBackend, ClientVersion, Root, Server } from './server';
+import type { ServerBackend, ClientInfo, Server } from './server';
 import type { Transport } from '@modelcontextprotocol/sdk/shared/transport.js';
 import type { Tool, CallToolResult, CallToolRequest } from '@modelcontextprotocol/sdk/types.js';
 import type { Client } from '@modelcontextprotocol/sdk/client/index.js';
@@ -36,15 +36,15 @@ export class ProxyBackend implements ServerBackend {
   private _mcpProviders: MCPProvider[];
   private _currentClient: Client | undefined;
   private _contextSwitchTool: Tool;
-  private _roots: Root[] = [];
+  private _clientInfo: ClientInfo | undefined;
 
   constructor(mcpProviders: MCPProvider[]) {
     this._mcpProviders = mcpProviders;
     this._contextSwitchTool = this._defineContextSwitchTool();
   }
 
-  async initialize(server: Server, clientVersion: ClientVersion, roots: Root[]): Promise<void> {
-    this._roots = roots;
+  async initialize(server: Server, clientInfo: ClientInfo): Promise<void> {
+    this._clientInfo = clientInfo;
   }
 
   async listTools(): Promise<Tool[]> {
@@ -124,7 +124,7 @@ export class ProxyBackend implements ServerBackend {
         listRoots: true,
       },
     });
-    client.setRequestHandler(mcpBundle.ListRootsRequestSchema, () => ({ roots: this._roots }));
+    client.setRequestHandler(mcpBundle.ListRootsRequestSchema, () => ({ roots: this._clientInfo?.roots || [] }));
     client.setRequestHandler(mcpBundle.PingRequestSchema, () => ({}));
 
     const transport = await factory.connect();

packages/playwright/src/mcp/sdk/server.ts

@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+import { fileURLToPath } from 'url';
+
 import { debug } from 'playwright-core/lib/utilsBundle';
 
 import * as mcpBundle from './bundle';
@@ -28,10 +30,15 @@ import type { Server } from '@modelcontextprotocol/sdk/server/index.js';
 
 const serverDebug = debug('pw:mcp:server');
 
-export type ClientVersion = { name: string, version: string };
+export type ClientInfo = {
+  name: string;
+  version: string;
+  roots: Root[];
+  timestamp: number;
+};
 
 export interface ServerBackend {
-  initialize?(server: Server, clientVersion: ClientVersion, roots: Root[]): Promise<void>;
+  initialize?(server: Server, clientInfo: ClientInfo): Promise<void>;
   listTools(): Promise<Tool[]>;
   callTool(name: string, args: CallToolRequest['params']['arguments']): Promise<CallToolResult>;
   serverClosed?(server: Server): void;
@@ -93,8 +100,15 @@ const initializeServer = async (server: Server, backend: ServerBackend, runHeart
     const { roots } = await server.listRoots();
     clientRoots = roots;
   }
-  const clientVersion = server.getClientVersion() ?? { name: 'unknown', version: 'unknown' };
-  await backend.initialize?.(server, clientVersion, clientRoots);
+
+  const clientInfo: ClientInfo = {
+    name: server.getClientVersion()?.name ?? 'unknown',
+    version: server.getClientVersion()?.version ?? 'unknown',
+    roots: clientRoots,
+    timestamp: Date.now(),
+  };
+
+  await backend.initialize?.(server, clientInfo);
   if (runHeartbeat)
     startHeartbeat(server);
 };
@@ -145,3 +159,11 @@ export async function start(serverBackendFactory: ServerBackendFactory, options:
     // eslint-disable-next-line no-console
   console.error(message);
 }
+
+export function firstRootPath(clientInfo: ClientInfo): string | undefined {
+  if (clientInfo.roots.length === 0)
+    return undefined;
+  const firstRootUri = clientInfo.roots[0]?.uri;
+  const url = firstRootUri ? new URL(firstRootUri) : undefined;
+  return url ? fileURLToPath(url) : undefined;
+}