chore: mark v0.0.28 (#503)

README.md

@@ -199,7 +199,7 @@ state [here](https://playwright.dev/docs/auth).
       "args": [
         "@playwright/mcp@latest",
         "--isolated",
-        "--storage-state={path/to/storage.json}
+        "--storage-state={path/to/storage.json}"
       ]
     }
   }

index.d.ts

@@ -18,6 +18,7 @@
 import type { Server } from '@modelcontextprotocol/sdk/server/index.js';
 import type { Config } from './config';
 import type { Transport } from '@modelcontextprotocol/sdk/shared/transport.js';
+import type { BrowserContext } from 'playwright';
 
 export type Connection = {
   server: Server;
@@ -25,5 +26,5 @@ export type Connection = {
   close(): Promise<void>;
 };
 
-export declare function createConnection(config?: Config): Promise<Connection>;
+export declare function createConnection(config?: Config, contextGetter?: () => Promise<BrowserContext>): Promise<Connection>;
 export {};

package-lock.json

@@ -1,16 +1,17 @@
 {
   "name": "@playwright/mcp",
-  "version": "0.0.27",
+  "version": "0.0.28",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@playwright/mcp",
-      "version": "0.0.27",
+      "version": "0.0.28",
       "license": "Apache-2.0",
       "dependencies": {
         "@modelcontextprotocol/sdk": "^1.11.0",
         "commander": "^13.1.0",
+        "debug": "^4.4.1",
         "playwright": "1.53.0-alpha-2025-05-27",
         "zod-to-json-schema": "^3.24.4"
       },
@@ -22,6 +23,7 @@
         "@eslint/js": "^9.19.0",
         "@playwright/test": "1.53.0-alpha-2025-05-27",
         "@stylistic/eslint-plugin": "^3.0.1",
+        "@types/debug": "^4.1.12",
         "@types/node": "^22.13.10",
         "@typescript-eslint/eslint-plugin": "^8.26.1",
         "@typescript-eslint/parser": "^8.26.1",
@@ -354,6 +356,16 @@
         "url": "https://github.com/sponsors/jonschlinkert"
       }
     },
+    "node_modules/@types/debug": {
+      "version": "4.1.12",
+      "resolved": "https://registry.npmjs.org/@types/debug/-/debug-4.1.12.tgz",
+      "integrity": "sha512-vIChWdVG3LG1SMxEvI/AK+FWJthlrqlTu7fbrlywTkkaONwk/UAGaULXRlf8vkzFBLVm0zkMdCquhL5aOjhXPQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@types/ms": "*"
+      }
+    },
     "node_modules/@types/estree": {
       "version": "1.0.6",
       "resolved": "https://registry.npmjs.org/@types/estree/-/estree-1.0.6.tgz",
@@ -375,6 +387,13 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/@types/ms": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/@types/ms/-/ms-2.1.0.tgz",
+      "integrity": "sha512-GsCCIZDE/p3i96vtEqx+7dBUGXrc7zeSK3wwPHIaRThS+9OhWIXRqzs4d6k1SVU8g91DrNRWxWUGhp5KXQb2VA==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/@types/node": {
       "version": "22.13.10",
       "resolved": "https://registry.npmjs.org/@types/node/-/node-22.13.10.tgz",
@@ -853,29 +872,6 @@
         "node": ">=18"
       }
     },
-    "node_modules/body-parser/node_modules/debug": {
-      "version": "4.4.0",
-      "resolved": "https://registry.npmjs.org/debug/-/debug-4.4.0.tgz",
-      "integrity": "sha512-6WTZ/IxCY/T6BALoZHaE4ctp9xm+Z5kY/pzYaCHRFeyVhojxlrm+46y68HA6hr0TcwEssoxNiDEUJQjfPZ/RYA==",
-      "license": "MIT",
-      "dependencies": {
-        "ms": "^2.1.3"
-      },
-      "engines": {
-        "node": ">=6.0"
-      },
-      "peerDependenciesMeta": {
-        "supports-color": {
-          "optional": true
-        }
-      }
-    },
-    "node_modules/body-parser/node_modules/ms": {
-      "version": "2.1.3",
-      "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.3.tgz",
-      "integrity": "sha512-6FlzubTLZG3J2a/NVCAleEhjzq5oxgHyaCU9yYXvcLsvoVaHJq/s5xXI6/XXP6tz7R9xAOtHnSO/tXtF3WRTlA==",
-      "license": "MIT"
-    },
     "node_modules/body-parser/node_modules/qs": {
       "version": "6.14.0",
       "resolved": "https://registry.npmjs.org/qs/-/qs-6.14.0.tgz",
@@ -1156,12 +1152,12 @@
       }
     },
     "node_modules/debug": {
-      "version": "4.3.6",
+      "version": "4.4.1",
-      "resolved": "https://registry.npmjs.org/debug/-/debug-4.3.6.tgz",
+      "resolved": "https://registry.npmjs.org/debug/-/debug-4.4.1.tgz",
-      "integrity": "sha512-O/09Bd4Z1fBrU4VzkhFqVgpPzaGbw6Sm9FEkBT1A/YBXQFGuuSxa1dN2nxgxS34JmKXqYx8CZAwEVoJFImUXIg==",
+      "integrity": "sha512-KcKCqiftBJcZr++7ykoDIEwSa3XWowTfNPo92BYxjXiyYEVrUQh2aLyhxBCwww+heortUFxEJYcRzosstTEBYQ==",
       "license": "MIT",
       "dependencies": {
-        "ms": "2.1.2"
+        "ms": "^2.1.3"
       },
       "engines": {
         "node": ">=6.0"
@@ -1826,6 +1822,29 @@
         "express": "^4.11 || 5 || ^5.0.0-beta.1"
       }
     },
+    "node_modules/express/node_modules/debug": {
+      "version": "4.3.6",
+      "resolved": "https://registry.npmjs.org/debug/-/debug-4.3.6.tgz",
+      "integrity": "sha512-O/09Bd4Z1fBrU4VzkhFqVgpPzaGbw6Sm9FEkBT1A/YBXQFGuuSxa1dN2nxgxS34JmKXqYx8CZAwEVoJFImUXIg==",
+      "license": "MIT",
+      "dependencies": {
+        "ms": "2.1.2"
+      },
+      "engines": {
+        "node": ">=6.0"
+      },
+      "peerDependenciesMeta": {
+        "supports-color": {
+          "optional": true
+        }
+      }
+    },
+    "node_modules/express/node_modules/ms": {
+      "version": "2.1.2",
+      "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.2.tgz",
+      "integrity": "sha512-sGkPx+VjMtmA6MX27oA4FBFELFCZZ4S4XqeGOXCv68tT+jb3vk/RyaKWP0PTKyWtmLSM0b+adUTEvbs1PEaH2w==",
+      "license": "MIT"
+    },
     "node_modules/fast-deep-equal": {
       "version": "3.1.3",
       "resolved": "https://registry.npmjs.org/fast-deep-equal/-/fast-deep-equal-3.1.3.tgz",
@@ -1930,29 +1949,6 @@
         "node": ">= 0.8"
       }
     },
-    "node_modules/finalhandler/node_modules/debug": {
-      "version": "4.4.0",
-      "resolved": "https://registry.npmjs.org/debug/-/debug-4.4.0.tgz",
-      "integrity": "sha512-6WTZ/IxCY/T6BALoZHaE4ctp9xm+Z5kY/pzYaCHRFeyVhojxlrm+46y68HA6hr0TcwEssoxNiDEUJQjfPZ/RYA==",
-      "license": "MIT",
-      "dependencies": {
-        "ms": "^2.1.3"
-      },
-      "engines": {
-        "node": ">=6.0"
-      },
-      "peerDependenciesMeta": {
-        "supports-color": {
-          "optional": true
-        }
-      }
-    },
-    "node_modules/finalhandler/node_modules/ms": {
-      "version": "2.1.3",
-      "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.3.tgz",
-      "integrity": "sha512-6FlzubTLZG3J2a/NVCAleEhjzq5oxgHyaCU9yYXvcLsvoVaHJq/s5xXI6/XXP6tz7R9xAOtHnSO/tXtF3WRTlA==",
-      "license": "MIT"
-    },
     "node_modules/find-root": {
       "version": "1.1.0",
       "resolved": "https://registry.npmjs.org/find-root/-/find-root-1.1.0.tgz",
@@ -3003,9 +2999,9 @@
       }
     },
     "node_modules/ms": {
-      "version": "2.1.2",
+      "version": "2.1.3",
-      "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.2.tgz",
+      "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.3.tgz",
-      "integrity": "sha512-sGkPx+VjMtmA6MX27oA4FBFELFCZZ4S4XqeGOXCv68tT+jb3vk/RyaKWP0PTKyWtmLSM0b+adUTEvbs1PEaH2w==",
+      "integrity": "sha512-6FlzubTLZG3J2a/NVCAleEhjzq5oxgHyaCU9yYXvcLsvoVaHJq/s5xXI6/XXP6tz7R9xAOtHnSO/tXtF3WRTlA==",
       "license": "MIT"
     },
     "node_modules/natural-compare": {
@@ -3713,12 +3709,6 @@
         "node": ">= 0.6"
       }
     },
-    "node_modules/send/node_modules/ms": {
-      "version": "2.1.3",
-      "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.3.tgz",
-      "integrity": "sha512-6FlzubTLZG3J2a/NVCAleEhjzq5oxgHyaCU9yYXvcLsvoVaHJq/s5xXI6/XXP6tz7R9xAOtHnSO/tXtF3WRTlA==",
-      "license": "MIT"
-    },
     "node_modules/serve-static": {
       "version": "2.1.0",
       "resolved": "https://registry.npmjs.org/serve-static/-/serve-static-2.1.0.tgz",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@playwright/mcp",
-  "version": "0.0.27",
+  "version": "0.0.28",
   "description": "Playwright Tools for MCP",
   "type": "module",
   "repository": {
@@ -37,6 +37,7 @@
   "dependencies": {
     "@modelcontextprotocol/sdk": "^1.11.0",
     "commander": "^13.1.0",
+    "debug": "^4.4.1",
     "playwright": "1.53.0-alpha-2025-05-27",
     "zod-to-json-schema": "^3.24.4"
   },
@@ -45,6 +46,7 @@
     "@eslint/js": "^9.19.0",
     "@playwright/test": "1.53.0-alpha-2025-05-27",
     "@stylistic/eslint-plugin": "^3.0.1",
+    "@types/debug": "^4.1.12",
     "@types/node": "^22.13.10",
     "@typescript-eslint/eslint-plugin": "^8.26.1",
     "@typescript-eslint/parser": "^8.26.1",

src/browserContextFactory.ts

@@ -0,0 +1,211 @@
+/**
+ * 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 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
+
+import debug from 'debug';
+import * as playwright from 'playwright';
+
+import type { FullConfig } from './config.js';
+
+const testDebug = debug('pw:mcp:test');
+
+export function contextFactory(browserConfig: FullConfig['browser']): BrowserContextFactory {
+  if (browserConfig.remoteEndpoint)
+    return new RemoteContextFactory(browserConfig);
+  if (browserConfig.cdpEndpoint)
+    return new CdpContextFactory(browserConfig);
+  if (browserConfig.isolated)
+    return new IsolatedContextFactory(browserConfig);
+  return new PersistentContextFactory(browserConfig);
+}
+
+export interface BrowserContextFactory {
+  createContext(): Promise<{ browserContext: playwright.BrowserContext, close: () => Promise<void> }>;
+}
+
+class BaseContextFactory implements BrowserContextFactory {
+  readonly browserConfig: FullConfig['browser'];
+  protected _browserPromise: Promise<playwright.Browser> | undefined;
+  readonly name: string;
+
+  constructor(name: string, browserConfig: FullConfig['browser']) {
+    this.name = name;
+    this.browserConfig = browserConfig;
+  }
+
+  protected async _obtainBrowser(): Promise<playwright.Browser> {
+    if (this._browserPromise)
+      return this._browserPromise;
+    testDebug(`obtain browser (${this.name})`);
+    this._browserPromise = this._doObtainBrowser();
+    void this._browserPromise.then(browser => {
+      browser.on('disconnected', () => {
+        this._browserPromise = undefined;
+      });
+    }).catch(() => {
+      this._browserPromise = undefined;
+    });
+    return this._browserPromise;
+  }
+
+  protected async _doObtainBrowser(): Promise<playwright.Browser> {
+    throw new Error('Not implemented');
+  }
+
+  async createContext(): Promise<{ browserContext: playwright.BrowserContext, close: () => Promise<void> }> {
+    testDebug(`create browser context (${this.name})`);
+    const browser = await this._obtainBrowser();
+    const browserContext = await this._doCreateContext(browser);
+    return { browserContext, close: () => this._closeBrowserContext(browserContext, browser) };
+  }
+
+  protected async _doCreateContext(browser: playwright.Browser): Promise<playwright.BrowserContext> {
+    throw new Error('Not implemented');
+  }
+
+  private async _closeBrowserContext(browserContext: playwright.BrowserContext, browser: playwright.Browser) {
+    testDebug(`close browser context (${this.name})`);
+    if (browser.contexts().length === 1)
+      this._browserPromise = undefined;
+    await browserContext.close().catch(() => {});
+    if (browser.contexts().length === 0) {
+      testDebug(`close browser (${this.name})`);
+      await browser.close().catch(() => {});
+    }
+  }
+}
+
+class IsolatedContextFactory extends BaseContextFactory {
+  constructor(browserConfig: FullConfig['browser']) {
+    super('isolated', browserConfig);
+  }
+
+  protected override async _doObtainBrowser(): Promise<playwright.Browser> {
+    const browserType = playwright[this.browserConfig.browserName];
+    return browserType.launch({
+      ...this.browserConfig.launchOptions,
+      handleSIGINT: false,
+      handleSIGTERM: false,
+    }).catch(error => {
+      if (error.message.includes('Executable doesn\'t exist'))
+        throw new Error(`Browser specified in your config is not installed. Either install it (likely) or change the config.`);
+      throw error;
+    });
+  }
+
+  protected override async _doCreateContext(browser: playwright.Browser): Promise<playwright.BrowserContext> {
+    return browser.newContext(this.browserConfig.contextOptions);
+  }
+}
+
+class CdpContextFactory extends BaseContextFactory {
+  constructor(browserConfig: FullConfig['browser']) {
+    super('cdp', browserConfig);
+  }
+
+  protected override async _doObtainBrowser(): Promise<playwright.Browser> {
+    return playwright.chromium.connectOverCDP(this.browserConfig.cdpEndpoint!);
+  }
+
+  protected override async _doCreateContext(browser: playwright.Browser): Promise<playwright.BrowserContext> {
+    return this.browserConfig.isolated ? await browser.newContext() : browser.contexts()[0];
+  }
+}
+
+class RemoteContextFactory extends BaseContextFactory {
+  constructor(browserConfig: FullConfig['browser']) {
+    super('remote', browserConfig);
+  }
+
+  protected override async _doObtainBrowser(): Promise<playwright.Browser> {
+    const url = new URL(this.browserConfig.remoteEndpoint!);
+    url.searchParams.set('browser', this.browserConfig.browserName);
+    if (this.browserConfig.launchOptions)
+      url.searchParams.set('launch-options', JSON.stringify(this.browserConfig.launchOptions));
+    return playwright[this.browserConfig.browserName].connect(String(url));
+  }
+
+  protected override async _doCreateContext(browser: playwright.Browser): Promise<playwright.BrowserContext> {
+    return browser.newContext();
+  }
+}
+
+class PersistentContextFactory implements BrowserContextFactory {
+  readonly browserConfig: FullConfig['browser'];
+  private _userDataDirs = new Set<string>();
+
+  constructor(browserConfig: FullConfig['browser']) {
+    this.browserConfig = browserConfig;
+  }
+
+  async createContext(): Promise<{ browserContext: playwright.BrowserContext, close: () => Promise<void> }> {
+    testDebug('create browser context (persistent)');
+    const userDataDir = this.browserConfig.userDataDir ?? await this._createUserDataDir();
+
+    this._userDataDirs.add(userDataDir);
+    testDebug('lock user data dir', userDataDir);
+
+    const browserType = playwright[this.browserConfig.browserName];
+    for (let i = 0; i < 5; i++) {
+      try {
+        const browserContext = await browserType.launchPersistentContext(userDataDir, {
+          ...this.browserConfig.launchOptions,
+          ...this.browserConfig.contextOptions,
+          handleSIGINT: false,
+          handleSIGTERM: false,
+        });
+        const close = () => this._closeBrowserContext(browserContext, userDataDir);
+        return { browserContext, close };
+      } catch (error: any) {
+        if (error.message.includes('Executable doesn\'t exist'))
+          throw new Error(`Browser specified in your config is not installed. Either install it (likely) or change the config.`);
+        if (error.message.includes('ProcessSingleton') || error.message.includes('Invalid URL')) {
+          // User data directory is already in use, try again.
+          await new Promise(resolve => setTimeout(resolve, 1000));
+          continue;
+        }
+        throw error;
+      }
+    }
+    throw new Error(`Browser is already in use for ${userDataDir}, use --isolated to run multiple instances of the same browser`);
+  }
+
+  private async _closeBrowserContext(browserContext: playwright.BrowserContext, userDataDir: string) {
+    testDebug('close browser context (persistent)');
+    testDebug('release user data dir', userDataDir);
+    await browserContext.close().catch(() => {});
+    this._userDataDirs.delete(userDataDir);
+    testDebug('close browser context complete (persistent)');
+  }
+
+  private async _createUserDataDir() {
+    let cacheDirectory: string;
+    if (process.platform === 'linux')
+      cacheDirectory = process.env.XDG_CACHE_HOME || path.join(os.homedir(), '.cache');
+    else if (process.platform === 'darwin')
+      cacheDirectory = path.join(os.homedir(), 'Library', 'Caches');
+    else if (process.platform === 'win32')
+      cacheDirectory = process.env.LOCALAPPDATA || path.join(os.homedir(), 'AppData', 'Local');
+    else
+      throw new Error('Unsupported platform: ' + process.platform);
+    const result = path.join(cacheDirectory, 'ms-playwright', `mcp-${this.browserConfig.launchOptions?.channel ?? this.browserConfig?.browserName}-profile`);
+    await fs.promises.mkdir(result, { recursive: true });
+    return result;
+  }
+}

src/config.ts

@@ -68,19 +68,21 @@ const defaultConfig: FullConfig = {
     allowedOrigins: undefined,
     blockedOrigins: undefined,
   },
+  server: {},
   outputDir: path.join(os.tmpdir(), 'playwright-mcp-output', sanitizeForFilePath(new Date().toISOString())),
 };
 
 type BrowserUserConfig = NonNullable<Config['browser']>;
 
 export type FullConfig = Config & {
-  browser: BrowserUserConfig & {
+  browser: Omit<BrowserUserConfig, 'browserName'> & {
-    browserName: NonNullable<BrowserUserConfig['browserName']>;
+    browserName: 'chromium' | 'firefox' | 'webkit';
     launchOptions: NonNullable<BrowserUserConfig['launchOptions']>;
     contextOptions: NonNullable<BrowserUserConfig['contextOptions']>;
   },
   network: NonNullable<Config['network']>,
   outputDir: string;
+  server: NonNullable<Config['server']>,
 };
 
 export async function resolveConfig(config: Config): Promise<FullConfig> {
@@ -256,6 +258,10 @@ function mergeConfig(base: FullConfig, overrides: Config): FullConfig {
     network: {
       ...pickDefined(base.network),
       ...pickDefined(overrides.network),
-    }
+    },
+    server: {
+      ...pickDefined(base.server),
+      ...pickDefined(overrides.server),
+    },
   } as FullConfig;
 }

src/connection.ts

@@ -14,22 +14,24 @@
  * limitations under the License.
  */
 
-import { Server } from '@modelcontextprotocol/sdk/server/index.js';
+import { Server as McpServer } from '@modelcontextprotocol/sdk/server/index.js';
 import { CallToolRequestSchema, ListToolsRequestSchema, Tool as McpTool } from '@modelcontextprotocol/sdk/types.js';
 import { zodToJsonSchema } from 'zod-to-json-schema';
 
-import { Context, packageJSON } from './context.js';
+import { Context } from './context.js';
 import { snapshotTools, visionTools } from './tools.js';
+import { packageJSON } from './package.js';
 
-import type { Transport } from '@modelcontextprotocol/sdk/shared/transport.js';
 import { FullConfig } from './config.js';
 
-export async function createConnection(config: FullConfig): Promise<Connection> {
+import type { BrowserContextFactory } from './browserContextFactory.js';
+
+export function createConnection(config: FullConfig, browserContextFactory: BrowserContextFactory): Connection {
   const allTools = config.vision ? visionTools : snapshotTools;
   const tools = allTools.filter(tool => !config.capabilities || tool.capability === 'core' || config.capabilities.includes(tool.capability));
 
-  const context = new Context(tools, config);
+  const context = new Context(tools, config, browserContextFactory);
-  const server = new Server({ name: 'Playwright', version: packageJSON.version }, {
+  const server = new McpServer({ name: 'Playwright', version: packageJSON.version }, {
     capabilities: {
       tools: {},
     }
@@ -74,25 +76,19 @@ export async function createConnection(config: FullConfig): Promise<Connection>
     }
   });
 
-  const connection = new Connection(server, context);
+  return new Connection(server, context);
-  return connection;
 }
 
 export class Connection {
-  readonly server: Server;
+  readonly server: McpServer;
   readonly context: Context;
 
-  constructor(server: Server, context: Context) {
+  constructor(server: McpServer, context: Context) {
     this.server = server;
     this.context = context;
-  }
+    this.server.oninitialized = () => {
-
+      this.context.clientVersion = this.server.getClientVersion();
-  async connect(transport: Transport) {
+    };
-    await this.server.connect(transport);
-    await new Promise<void>(resolve => {
-      this.server.oninitialized = () => resolve();
-    });
-    this.context.clientVersion = this.server.getClientVersion();
   }
 
   async close() {

src/context.ts

@@ -14,11 +14,7 @@
  * limitations under the License.
  */
 
-import fs from 'node:fs';
+import debug from 'debug';
-import url from 'node:url';
-import os from 'node:os';
-import path from 'node:path';
-
 import * as playwright from 'playwright';
 
 import { callOnPageNoTrace, waitForCompletion } from './tools/utils.js';
@@ -29,20 +25,19 @@ 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 { FullConfig } from './config.js';
+import type { BrowserContextFactory } from './browserContextFactory.js';
 
 type PendingAction = {
   dialogShown: ManualPromise<void>;
 };
 
-type BrowserContextAndBrowser = {
+const testDebug = debug('pw:mcp:test');
-  browser?: playwright.Browser;
-  browserContext: playwright.BrowserContext;
-};
 
 export class Context {
   readonly tools: Tool[];
   readonly config: FullConfig;
-  private _browserContextPromise: Promise<BrowserContextAndBrowser> | undefined;
+  private _browserContextPromise: Promise<{ browserContext: playwright.BrowserContext, close: () => Promise<void> }> | undefined;
+  private _browserContextFactory: BrowserContextFactory;
   private _tabs: Tab[] = [];
   private _currentTab: Tab | undefined;
   private _modalStates: (ModalState & { tab: Tab })[] = [];
@@ -50,9 +45,11 @@ export class Context {
   private _downloads: { download: playwright.Download, finished: boolean, outputFile: string }[] = [];
   clientVersion: { name: string; version: string; } | undefined;
 
-  constructor(tools: Tool[], config: FullConfig) {
+  constructor(tools: Tool[], config: FullConfig, browserContextFactory: BrowserContextFactory) {
     this.tools = tools;
     this.config = config;
+    this._browserContextFactory = browserContextFactory;
+    testDebug('create context');
   }
 
   clientSupportsImages(): boolean {
@@ -297,15 +294,15 @@ ${code.join('\n')}
     if (!this._browserContextPromise)
       return;
 
+    testDebug('close context');
+
     const promise = this._browserContextPromise;
     this._browserContextPromise = undefined;
 
-    await promise.then(async ({ browserContext, browser }) => {
+    await promise.then(async ({ browserContext, close }) => {
       if (this.config.saveTrace)
         await browserContext.tracing.stop();
-      await browserContext.close().then(async () => {
+      await close();
-        await browser?.close();
-      }).catch(() => {});
     });
   }
 
@@ -333,8 +330,10 @@ ${code.join('\n')}
     return this._browserContextPromise;
   }
 
-  private async _setupBrowserContext(): Promise<BrowserContextAndBrowser> {
+  private async _setupBrowserContext(): Promise<{ browserContext: playwright.BrowserContext, close: () => Promise<void> }> {
-    const { browser, browserContext } = await this._createBrowserContext();
+    // TODO: move to the browser context factory to make it based on isolation mode.
+    const result = await this._browserContextFactory.createContext();
+    const { browserContext } = result;
     await this._setupRequestInterception(browserContext);
     for (const page of browserContext.pages())
       this._onPageCreated(page);
@@ -347,75 +346,6 @@ ${code.join('\n')}
         sources: false,
       });
     }
-    return { browser, browserContext };
+    return result;
-  }
-
-  private async _createBrowserContext(): Promise<BrowserContextAndBrowser> {
-    if (this.config.browser?.remoteEndpoint) {
-      const url = new URL(this.config.browser?.remoteEndpoint);
-      if (this.config.browser.browserName)
-        url.searchParams.set('browser', this.config.browser.browserName);
-      if (this.config.browser.launchOptions)
-        url.searchParams.set('launch-options', JSON.stringify(this.config.browser.launchOptions));
-      const browser = await playwright[this.config.browser?.browserName ?? 'chromium'].connect(String(url));
-      const browserContext = await browser.newContext();
-      return { browser, browserContext };
-    }
-
-    if (this.config.browser?.cdpEndpoint) {
-      const browser = await playwright.chromium.connectOverCDP(this.config.browser.cdpEndpoint);
-      const browserContext = this.config.browser.isolated ? await browser.newContext() : browser.contexts()[0];
-      return { browser, browserContext };
-    }
-
-    return this.config.browser?.isolated ?
-      await createIsolatedContext(this.config.browser) :
-      await launchPersistentContext(this.config.browser);
   }
 }
-
-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);
-    return { browser, browserContext };
-  } catch (error: any) {
-    if (error.message.includes('Executable doesn\'t exist'))
-      throw new Error(`Browser specified in your config is not installed. Either install it (likely) or change the config.`);
-    throw error;
-  }
-}
-
-async function launchPersistentContext(browserConfig: FullConfig['browser']): Promise<BrowserContextAndBrowser> {
-  try {
-    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 });
-    return { browserContext };
-  } catch (error: any) {
-    if (error.message.includes('Executable doesn\'t exist'))
-      throw new Error(`Browser specified in your config is not installed. Either install it (likely) or change the config.`);
-    throw error;
-  }
-}
-
-async function createUserDataDir(browserConfig: FullConfig['browser']) {
-  let cacheDirectory: string;
-  if (process.platform === 'linux')
-    cacheDirectory = process.env.XDG_CACHE_HOME || path.join(os.homedir(), '.cache');
-  else if (process.platform === 'darwin')
-    cacheDirectory = path.join(os.homedir(), 'Library', 'Caches');
-  else if (process.platform === 'win32')
-    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`);
-  await fs.promises.mkdir(result, { recursive: true });
-  return result;
-}
-
-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

@@ -16,10 +16,30 @@
 
 import { Connection, createConnection as createConnectionImpl } from './connection.js';
 import { resolveConfig } from './config.js';
+import { contextFactory } from './browserContextFactory.js';
 
 import type { Config } from '../config.js';
+import type { BrowserContext } from 'playwright';
+import type { BrowserContextFactory } from './browserContextFactory.js';
 
-export async function createConnection(userConfig: Config = {}): Promise<Connection> {
+export async function createConnection(userConfig: Config = {}, contextGetter?: () => Promise<BrowserContext>): Promise<Connection> {
   const config = await resolveConfig(userConfig);
-  return createConnectionImpl(config);
+  const factory = contextGetter ? new SimpleBrowserContextFactory(contextGetter) : contextFactory(config.browser);
+  return createConnectionImpl(config, factory);
+}
+
+class SimpleBrowserContextFactory implements BrowserContextFactory {
+  private readonly _contextGetter: () => Promise<BrowserContext>;
+
+  constructor(contextGetter: () => Promise<BrowserContext>) {
+    this._contextGetter = contextGetter;
+  }
+
+  async createContext(): Promise<{ browserContext: BrowserContext, close: () => Promise<void> }> {
+    const browserContext = await this._contextGetter();
+    return {
+      browserContext,
+      close: () => browserContext.close()
+    };
+  }
 }

src/package.ts

@@ -0,0 +1,22 @@
+/**
+ * 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 'node:fs';
+import url from 'node:url';
+import path from 'node:path';
+
+const __filename = url.fileURLToPath(import.meta.url);
+export const packageJSON = JSON.parse(fs.readFileSync(path.join(path.dirname(__filename), '..', 'package.json'), 'utf8'));

src/program.ts

@@ -15,14 +15,13 @@
  */
 
 import { program } from 'commander';
-
-import { startHttpTransport, startStdioTransport } from './transport.js';
-import { resolveCLIConfig } from './config.js';
 // @ts-ignore
 import { startTraceViewerServer } from 'playwright-core/lib/server';
 
-import type { Connection } from './connection.js';
+import { startHttpTransport, startStdioTransport } from './transport.js';
-import { packageJSON } from './context.js';
+import { resolveCLIConfig } from './config.js';
+import { Server } from './server.js';
+import { packageJSON } from './package.js';
 
 program
     .version('Version ' + packageJSON.version)
@@ -54,13 +53,13 @@ program
     .option('--vision', 'Run server that uses screenshots (Aria snapshots are used by default)')
     .action(async options => {
       const config = await resolveCLIConfig(options);
-      const connectionList: Connection[] = [];
+      const server = new Server(config);
-      setupExitWatchdog(connectionList);
+      server.setupExitWatchdog();
 
-      if (options.port)
+      if (config.server.port !== undefined)
-        startHttpTransport(config, +options.port, options.host, connectionList);
+        startHttpTransport(server);
       else
-        await startStdioTransport(config, connectionList);
+        await startStdioTransport(server);
 
       if (config.saveTrace) {
         const server = await startTraceViewerServer();
@@ -71,21 +70,8 @@ program
       }
     });
 
-function setupExitWatchdog(connectionList: Connection[]) {
-  const handleExit = async () => {
-    setTimeout(() => process.exit(0), 15000);
-    for (const connection of connectionList)
-      await connection.close();
-    process.exit(0);
-  };
-
-  process.stdin.on('close', handleExit);
-  process.on('SIGINT', handleExit);
-  process.on('SIGTERM', handleExit);
-}
-
 function semicolonSeparatedList(value: string): string[] {
   return value.split(';').map(v => v.trim());
 }
 
-program.parse(process.argv);
+void program.parseAsync(process.argv);

src/server.ts

@@ -0,0 +1,59 @@
+/**
+ * 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 { createConnection } from './connection.js';
+import { contextFactory } from './browserContextFactory.js';
+
+import type { FullConfig } from './config.js';
+import type { Connection } from './connection.js';
+import type { Transport } from '@modelcontextprotocol/sdk/shared/transport.js';
+import type { BrowserContextFactory } from './browserContextFactory.js';
+
+export class Server {
+  readonly config: FullConfig;
+  private _connectionList: Connection[] = [];
+  private _browserConfig: FullConfig['browser'];
+  private _contextFactory: BrowserContextFactory;
+
+  constructor(config: FullConfig) {
+    this.config = config;
+    this._browserConfig = config.browser;
+    this._contextFactory = contextFactory(this._browserConfig);
+  }
+
+  async createConnection(transport: Transport): Promise<Connection> {
+    const connection = createConnection(this.config, this._contextFactory);
+    this._connectionList.push(connection);
+    await connection.server.connect(transport);
+    return connection;
+  }
+
+  setupExitWatchdog() {
+    let isExiting = false;
+    const handleExit = async () => {
+      if (isExiting)
+        return;
+      isExiting = true;
+      setTimeout(() => process.exit(0), 15000);
+      await Promise.all(this._connectionList.map(connection => connection.close()));
+      process.exit(0);
+    };
+
+    process.stdin.on('close', handleExit);
+    process.on('SIGINT', handleExit);
+    process.on('SIGTERM', handleExit);
+  }
+}

src/transport.ts

@@ -18,22 +18,20 @@ import http from 'node:http';
 import assert from 'node:assert';
 import crypto from 'node: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 { createConnection } from './connection.js';
+import type { Server } from './server.js';
 
-import type { Connection } from './connection.js';
+export async function startStdioTransport(server: Server) {
-import type { FullConfig } from './config.js';
+  await server.createConnection(new StdioServerTransport());
-
-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: FullConfig, req: http.IncomingMessage, res: http.ServerResponse, url: URL, sessions: Map<string, SSEServerTransport>, connectionList: Connection[]) {
+const testDebug = debug('pw:mcp:test');
+
+async function handleSSE(server: Server, req: http.IncomingMessage, res: http.ServerResponse, url: URL, sessions: Map<string, SSEServerTransport>) {
   if (req.method === 'POST') {
     const sessionId = url.searchParams.get('sessionId');
     if (!sessionId) {
@@ -51,15 +49,13 @@ async function handleSSE(config: FullConfig, req: http.IncomingMessage, res: htt
   } else if (req.method === 'GET') {
     const transport = new SSEServerTransport('/sse', res);
     sessions.set(transport.sessionId, transport);
-    const connection = await createConnection(config);
+    testDebug(`create SSE session: ${transport.sessionId}`);
-    await connection.connect(transport);
+    const connection = await server.createConnection(transport);
-    connectionList.push(connection);
     res.on('close', () => {
+      testDebug(`delete SSE session: ${transport.sessionId}`);
       sessions.delete(transport.sessionId);
-      connection.close().catch(e => {
+      // eslint-disable-next-line no-console
-        // eslint-disable-next-line no-console
+      void connection.close().catch(e => console.error(e));
-        console.error(e);
-      });
     });
     return;
   }
@@ -68,7 +64,7 @@ async function handleSSE(config: FullConfig, req: http.IncomingMessage, res: htt
   res.end('Method not allowed');
 }
 
-async function handleStreamable(config: FullConfig, req: http.IncomingMessage, res: http.ServerResponse, sessions: Map<string, StreamableHTTPServerTransport>, connectionList: Connection[]) {
+async function handleStreamable(server: Server, req: http.IncomingMessage, res: http.ServerResponse, sessions: Map<string, StreamableHTTPServerTransport>) {
   const sessionId = req.headers['mcp-session-id'] as string | undefined;
   if (sessionId) {
     const transport = sessions.get(sessionId);
@@ -91,12 +87,8 @@ async function handleStreamable(config: FullConfig, req: http.IncomingMessage, r
       if (transport.sessionId)
         sessions.delete(transport.sessionId);
     };
-    const connection = await createConnection(config);
+    await server.createConnection(transport);
-    connectionList.push(connection);
+    await transport.handleRequest(req, res);
-    await Promise.all([
-      connection.connect(transport),
-      transport.handleRequest(req, res),
-    ]);
     return;
   }
 
@@ -104,17 +96,18 @@ async function handleStreamable(config: FullConfig, req: http.IncomingMessage, r
   res.end('Invalid request');
 }
 
-export function startHttpTransport(config: FullConfig, port: number, hostname: string | undefined, connectionList: Connection[]) {
+export function startHttpTransport(server: Server) {
   const sseSessions = new Map<string, SSEServerTransport>();
   const streamableSessions = new Map<string, StreamableHTTPServerTransport>();
   const httpServer = http.createServer(async (req, res) => {
     const url = new URL(`http://localhost${req.url}`);
     if (url.pathname.startsWith('/mcp'))
-      await handleStreamable(config, req, res, streamableSessions, connectionList);
+      await handleStreamable(server, req, res, streamableSessions);
     else
-      await handleSSE(config, req, res, url, sseSessions, connectionList);
+      await handleSSE(server, req, res, url, sseSessions);
   });
-  httpServer.listen(port, hostname, () => {
+  const { host, port } = server.config.server;
+  httpServer.listen(port, host, () => {
     const address = httpServer.address();
     assert(address, 'Could not bind server socket');
     let url: string;

tests/capabilities.spec.ts

@@ -77,7 +77,7 @@ test('test vision tool list', async ({ visionClient }) => {
 });
 
 test('test capabilities', async ({ startClient }) => {
-  const client = await startClient({
+  const { client } = await startClient({
     args: ['--caps="core"'],
   });
   const { tools } = await client.listTools();

tests/cdp.spec.ts

@@ -18,7 +18,7 @@ import { test, expect } from './fixtures.js';
 
 test('cdp server', async ({ cdpServer, startClient, server }) => {
   await cdpServer.start();
-  const client = await startClient({ args: [`--cdp-endpoint=${cdpServer.endpoint}`] });
+  const { client } = await startClient({ args: [`--cdp-endpoint=${cdpServer.endpoint}`] });
   expect(await client.callTool({
     name: 'browser_navigate',
     arguments: { url: server.HELLO_WORLD },
@@ -27,7 +27,7 @@ test('cdp server', async ({ cdpServer, startClient, server }) => {
 
 test('cdp server reuse tab', async ({ cdpServer, startClient, server }) => {
   const browserContext = await cdpServer.start();
-  const client = await startClient({ args: [`--cdp-endpoint=${cdpServer.endpoint}`] });
+  const { client } = await startClient({ args: [`--cdp-endpoint=${cdpServer.endpoint}`] });
 
   const [page] = browserContext.pages();
   await page.goto(server.HELLO_WORLD);
@@ -58,7 +58,7 @@ test('cdp server reuse tab', async ({ cdpServer, startClient, server }) => {
 });
 
 test('should throw connection error and allow re-connecting', async ({ cdpServer, startClient, server }) => {
-  const client = await startClient({ args: [`--cdp-endpoint=${cdpServer.endpoint}`] });
+  const { client } = await startClient({ args: [`--cdp-endpoint=${cdpServer.endpoint}`] });
 
   server.setContent('/', `
     <title>Title</title>

tests/config.spec.ts

@@ -33,7 +33,7 @@ test('config user data dir', async ({ startClient, server }, testInfo) => {
   const configPath = testInfo.outputPath('config.json');
   await fs.promises.writeFile(configPath, JSON.stringify(config, null, 2));
 
-  const client = await startClient({ args: ['--config', configPath] });
+  const { client } = await startClient({ args: ['--config', configPath] });
   expect(await client.callTool({
     name: 'browser_navigate',
     arguments: { url: server.PREFIX },
@@ -54,7 +54,7 @@ test.describe(() => {
     const configPath = testInfo.outputPath('config.json');
     await fs.promises.writeFile(configPath, JSON.stringify(config, null, 2));
 
-    const client = await startClient({ args: ['--config', configPath] });
+    const { client } = await startClient({ args: ['--config', configPath] });
     expect(await client.callTool({
       name: 'browser_navigate',
       arguments: { url: 'data:text/html,<script>document.title = navigator.userAgent</script>' },

tests/device.spec.ts

@@ -17,7 +17,7 @@
 import { test, expect } from './fixtures.js';
 
 test('--device should work', async ({ startClient, server }) => {
-  const client = await startClient({
+  const { client } = await startClient({
     args: ['--device', 'iPhone 15'],
   });
 

tests/files.spec.ts

@@ -101,7 +101,7 @@ The tool "browser_file_upload" can only be used when there is related modal stat
 });
 
 test('clicking on download link emits download', async ({ startClient, server }, testInfo) => {
-  const client = await startClient({
+  const { client } = await startClient({
     config: { outputDir: testInfo.outputPath('output') },
   });
 
@@ -125,7 +125,7 @@ test('clicking on download link emits download', async ({ startClient, server },
 });
 
 test('navigating to download link emits download', async ({ startClient, server, mcpBrowser }, testInfo) => {
-  const client = await startClient({
+  const { client } = await startClient({
     config: { outputDir: testInfo.outputPath('output') },
   });
 

tests/fixtures.ts

@@ -40,7 +40,7 @@ type CDPServer = {
 type TestFixtures = {
   client: Client;
   visionClient: Client;
-  startClient: (options?: { clientName?: string, args?: string[], config?: Config }) => Promise<Client>;
+  startClient: (options?: { clientName?: string, args?: string[], config?: Config }) => Promise<{ client: Client, stderr: () => string }>;
   wsEndpoint: string;
   cdpServer: CDPServer;
   server: TestServer;
@@ -55,11 +55,13 @@ type WorkerFixtures = {
 export const test = baseTest.extend<TestFixtures & TestOptions, WorkerFixtures>({
 
   client: async ({ startClient }, use) => {
-    await use(await startClient());
+    const { client } = await startClient();
+    await use(client);
   },
 
   visionClient: async ({ startClient }, use) => {
-    await use(await startClient({ args: ['--vision'] }));
+    const { client } = await startClient({ args: ['--vision'] });
+    await use(client);
   },
 
   startClient: async ({ mcpHeadless, mcpBrowser, mcpMode }, use, testInfo) => {
@@ -85,9 +87,13 @@ export const test = baseTest.extend<TestFixtures & TestOptions, WorkerFixtures>(
 
       client = new Client({ name: options?.clientName ?? 'test', version: '1.0.0' });
       const transport = createTransport(args, mcpMode);
+      let stderr = '';
+      transport.stderr?.on('data', data => {
+        stderr += data.toString();
+      });
       await client.connect(transport);
       await client.ping();
-      return client;
+      return { client, stderr: () => stderr };
     });
 
     await client?.close();
@@ -168,7 +174,13 @@ function createTransport(args: string[], mcpMode: TestOptions['mcpMode']) {
     command: 'node',
     args: [path.join(path.dirname(__filename), '../cli.js'), ...args],
     cwd: path.join(path.dirname(__filename), '..'),
-    env: process.env as Record<string, string>,
+    stderr: 'pipe',
+    env: {
+      ...process.env,
+      DEBUG: 'pw:mcp:test',
+      DEBUG_COLORS: '0',
+      DEBUG_HIDE_DATE: '1',
+    },
   });
 }
 
@@ -225,3 +237,7 @@ export const expect = baseExpect.extend({
     };
   },
 });
+
+export function formatOutput(output: string): string[] {
+  return output.split('\n').map(line => line.replace(/^pw:mcp:test /, '').replace(/test-results.*/, '').trim()).filter(Boolean);
+}

tests/launch.spec.ts

@@ -16,9 +16,10 @@
 
 import fs from 'fs';
 
-import { test, expect } from './fixtures.js';
+import { test, expect, formatOutput } from './fixtures.js';
 
-test('test reopen browser', async ({ client, server }) => {
+test('test reopen browser', async ({ startClient, server }) => {
+  const { client, stderr } = await startClient();
   await client.callTool({
     name: 'browser_navigate',
     arguments: { url: server.HELLO_WORLD },
@@ -32,10 +33,31 @@ test('test reopen browser', async ({ client, server }) => {
     name: 'browser_navigate',
     arguments: { url: server.HELLO_WORLD },
   })).toContainTextContent(`- generic [ref=e1]: Hello, world!`);
+
+  await client.close();
+
+  if (process.platform === 'win32')
+    return;
+
+  await expect.poll(() => formatOutput(stderr()), { timeout: 0 }).toEqual([
+    'create context',
+    'create browser context (persistent)',
+    'lock user data dir',
+    'close context',
+    'close browser context (persistent)',
+    'release user data dir',
+    'close browser context complete (persistent)',
+    'create browser context (persistent)',
+    'lock user data dir',
+    'close context',
+    'close browser context (persistent)',
+    'release user data dir',
+    'close browser context complete (persistent)',
+  ]);
 });
 
 test('executable path', async ({ startClient, server }) => {
-  const client = await startClient({ args: [`--executable-path=bogus`] });
+  const { client } = await startClient({ args: [`--executable-path=bogus`] });
   const response = await client.callTool({
     name: 'browser_navigate',
     arguments: { url: server.HELLO_WORLD },
@@ -53,7 +75,7 @@ test('persistent context', async ({ startClient, server }) => {
     </script>
   `, 'text/html');
 
-  const client = await startClient();
+  const { client } = await startClient();
   const response = await client.callTool({
     name: 'browser_navigate',
     arguments: { url: server.PREFIX },
@@ -66,7 +88,7 @@ test('persistent context', async ({ startClient, server }) => {
     name: 'browser_close',
   });
 
-  const client2 = await startClient();
+  const { client: client2 } = await startClient();
   const response2 = await client2.callTool({
     name: 'browser_navigate',
     arguments: { url: server.PREFIX },
@@ -85,18 +107,18 @@ test('isolated context', async ({ startClient, server }) => {
     </script>
   `, 'text/html');
 
-  const client = await startClient({ args: [`--isolated`] });
+  const { client: client1 } = await startClient({ args: [`--isolated`] });
-  const response = await client.callTool({
+  const response = await client1.callTool({
     name: 'browser_navigate',
     arguments: { url: server.PREFIX },
   });
   expect(response).toContainTextContent(`Storage: NO`);
 
-  await client.callTool({
+  await client1.callTool({
     name: 'browser_close',
   });
 
-  const client2 = await startClient({ args: [`--isolated`] });
+  const { client: client2 } = await startClient({ args: [`--isolated`] });
   const response2 = await client2.callTool({
     name: 'browser_navigate',
     arguments: { url: server.PREFIX },
@@ -123,7 +145,7 @@ test('isolated context with storage state', async ({ startClient, server }, test
     </script>
   `, 'text/html');
 
-  const client = await startClient({ args: [
+  const { client } = await startClient({ args: [
     `--isolated`,
     `--storage-state=${storageStatePath}`,
   ] });

tests/pdf.spec.ts

@@ -19,7 +19,7 @@ import fs from 'fs';
 import { test, expect } from './fixtures.js';
 
 test('save as pdf unavailable', async ({ startClient, server }) => {
-  const client = await startClient({ args: ['--caps="no-pdf"'] });
+  const { client } = await startClient({ args: ['--caps="no-pdf"'] });
   await client.callTool({
     name: 'browser_navigate',
     arguments: { url: server.HELLO_WORLD },
@@ -31,7 +31,7 @@ test('save as pdf unavailable', async ({ startClient, server }) => {
 });
 
 test('save as pdf', async ({ startClient, mcpBrowser, server }, testInfo) => {
-  const client = await startClient({
+  const { client } = await startClient({
     config: { outputDir: testInfo.outputPath('output') },
   });
 
@@ -51,7 +51,7 @@ test('save as pdf', async ({ startClient, mcpBrowser, server }, testInfo) => {
 test('save as pdf (filename: output.pdf)', async ({ startClient, mcpBrowser, server }, testInfo) => {
   const outputDir = testInfo.outputPath('output');
   test.skip(!!mcpBrowser && !['chromium', 'chrome', 'msedge'].includes(mcpBrowser), 'Save as PDF is only supported in Chromium.');
-  const client = await startClient({
+  const { client } = await startClient({
     config: { outputDir },
   });
 

tests/request-blocking.spec.ts

@@ -37,7 +37,7 @@ test('default to allow all', async ({ server, client }) => {
 });
 
 test('blocked works', async ({ startClient }) => {
-  const client = await startClient({
+  const { client } = await startClient({
     args: ['--blocked-origins', 'microsoft.com;example.com;playwright.dev']
   });
   const result = await fetchPage(client, 'https://example.com/');
@@ -46,7 +46,7 @@ test('blocked works', async ({ startClient }) => {
 
 test('allowed works', async ({ server, startClient }) => {
   server.setContent('/ppp', 'content:PPP', 'text/html');
-  const client = await startClient({
+  const { client } = await startClient({
     args: ['--allowed-origins', `microsoft.com;${new URL(server.PREFIX).host};playwright.dev`]
   });
   const result = await fetchPage(client, server.PREFIX + 'ppp');
@@ -54,7 +54,7 @@ test('allowed works', async ({ server, startClient }) => {
 });
 
 test('blocked takes precedence', async ({ startClient }) => {
-  const client = await startClient({
+  const { client } = await startClient({
     args: [
       '--blocked-origins', 'example.com',
       '--allowed-origins', 'example.com',
@@ -65,7 +65,7 @@ test('blocked takes precedence', async ({ startClient }) => {
 });
 
 test('allowed without blocked blocks all non-explicitly specified origins', async ({ startClient }) => {
-  const client = await startClient({
+  const { client } = await startClient({
     args: ['--allowed-origins', 'playwright.dev'],
   });
   const result = await fetchPage(client, 'https://example.com/');
@@ -74,7 +74,7 @@ test('allowed without blocked blocks all non-explicitly specified origins', asyn
 
 test('blocked without allowed allows non-explicitly specified origins', async ({ server, startClient }) => {
   server.setContent('/ppp', 'content:PPP', 'text/html');
-  const client = await startClient({
+  const { client } = await startClient({
     args: ['--blocked-origins', 'example.com'],
   });
   const result = await fetchPage(client, server.PREFIX + 'ppp');

tests/screenshot.spec.ts

@@ -19,7 +19,7 @@ import fs from 'fs';
 import { test, expect } from './fixtures.js';
 
 test('browser_take_screenshot (viewport)', async ({ startClient, server }, testInfo) => {
-  const client = await startClient({
+  const { client } = await startClient({
     config: { outputDir: testInfo.outputPath('output') },
   });
   expect(await client.callTool({
@@ -45,7 +45,7 @@ test('browser_take_screenshot (viewport)', async ({ startClient, server }, testI
 });
 
 test('browser_take_screenshot (element)', async ({ startClient, server }, testInfo) => {
-  const client = await startClient({
+  const { client } = await startClient({
     config: { outputDir: testInfo.outputPath('output') },
   });
   expect(await client.callTool({
@@ -76,7 +76,7 @@ test('browser_take_screenshot (element)', async ({ startClient, server }, testIn
 
 test('--output-dir should work', async ({ startClient, server }, testInfo) => {
   const outputDir = testInfo.outputPath('output');
-  const client = await startClient({
+  const { client } = await startClient({
     config: { outputDir },
   });
   expect(await client.callTool({
@@ -98,7 +98,7 @@ for (const raw of [undefined, true]) {
   test(`browser_take_screenshot (raw: ${raw})`, async ({ startClient, server }, testInfo) => {
     const outputDir = testInfo.outputPath('output');
     const ext = raw ? 'png' : 'jpeg';
-    const client = await startClient({
+    const { client } = await startClient({
       config: { outputDir },
     });
     expect(await client.callTool({
@@ -138,7 +138,7 @@ for (const raw of [undefined, true]) {
 
 test('browser_take_screenshot (filename: "output.jpeg")', async ({ startClient, server }, testInfo) => {
   const outputDir = testInfo.outputPath('output');
-  const client = await startClient({
+  const { client } = await startClient({
     config: { outputDir },
   });
   expect(await client.callTool({
@@ -174,7 +174,7 @@ test('browser_take_screenshot (filename: "output.jpeg")', async ({ startClient,
 
 test('browser_take_screenshot (imageResponses=omit)', async ({ startClient, server }, testInfo) => {
   const outputDir = testInfo.outputPath('output');
-  const client = await startClient({
+  const { client } = await startClient({
     config: {
       outputDir,
       imageResponses: 'omit',
@@ -205,7 +205,7 @@ test('browser_take_screenshot (imageResponses=omit)', async ({ startClient, serv
 test('browser_take_screenshot (cursor)', async ({ startClient, server }, testInfo) => {
   const outputDir = testInfo.outputPath('output');
 
-  const client = await startClient({
+  const { client } = await startClient({
     clientName: 'cursor:vscode',
     config: { outputDir },
   });

tests/sse.spec.ts

@@ -14,96 +14,233 @@
  * limitations under the License.
  */
 
+import fs from 'node:fs';
 import url from 'node:url';
-import http from 'node:http';
+
-import { spawn } from 'node:child_process';
+import { ChildProcess, spawn } from 'node:child_process';
 import path from 'node:path';
-import type { AddressInfo } from 'node:net';
 import { SSEClientTransport } from '@modelcontextprotocol/sdk/client/sse.js';
-import { SSEServerTransport } from '@modelcontextprotocol/sdk/server/sse.js';
 import { StreamableHTTPClientTransport } from '@modelcontextprotocol/sdk/client/streamableHttp.js';
 import { Client } from '@modelcontextprotocol/sdk/client/index.js';
 
-import { createConnection } from '@playwright/mcp';
-
 import { test as baseTest, expect } from './fixtures.js';
+import type { Config } from '../config.d.ts';
 
 // NOTE: Can be removed when we drop Node.js 18 support and changed to import.meta.filename.
 const __filename = url.fileURLToPath(import.meta.url);
 
-const test = baseTest.extend<{ serverEndpoint: string }>({
+const test = baseTest.extend<{ serverEndpoint: (options?: { args?: string[], noPort?: boolean }) => Promise<{ url: URL, stderr: () => string }> }>({
-  serverEndpoint: async ({}, use) => {
+  serverEndpoint: async ({ mcpHeadless }, use, testInfo) => {
-    const cp = spawn('node', [path.join(path.dirname(__filename), '../cli.js'), '--port', '0'], { stdio: 'pipe' });
+    let cp: ChildProcess | undefined;
-    try {
+    const userDataDir = testInfo.outputPath('user-data-dir');
+    await use(async (options?: { args?: string[], noPort?: boolean }) => {
+      if (cp)
+        throw new Error('Process already running');
+
+      cp = spawn('node', [
+        path.join(path.dirname(__filename), '../cli.js'),
+        ...(options?.noPort ? [] : ['--port=0']),
+        '--user-data-dir=' + userDataDir,
+        ...(mcpHeadless ? ['--headless'] : []),
+        ...(options?.args || []),
+      ], {
+        stdio: 'pipe',
+        env: {
+          ...process.env,
+          DEBUG: 'pw:mcp:test',
+          DEBUG_COLORS: '0',
+          DEBUG_HIDE_DATE: '1',
+        },
+      });
       let stderr = '';
-      const url = await new Promise<string>(resolve => cp.stderr?.on('data', data => {
+      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]);
       }));
 
-      await use(url);
+      return { url: new URL(url), stderr: () => stderr };
-    } finally {
+    });
-      cp.kill();
+    cp?.kill('SIGTERM');
-    }
   },
 });
 
 test('sse transport', async ({ serverEndpoint }) => {
-  const transport = new SSEClientTransport(new URL(serverEndpoint));
+  const { url } = await serverEndpoint();
+  const transport = new SSEClientTransport(url);
   const client = new Client({ name: 'test', version: '1.0.0' });
   await client.connect(transport);
   await client.ping();
 });
 
+test('sse transport (config)', async ({ serverEndpoint }) => {
+  const config: Config = {
+    server: {
+      port: 0,
+    }
+  };
+  const configFile = test.info().outputPath('config.json');
+  await fs.promises.writeFile(configFile, JSON.stringify(config, null, 2));
+
+  const { url } = await serverEndpoint({ noPort: true, args: ['--config=' + configFile] });
+  const transport = new SSEClientTransport(url);
+  const client = new Client({ name: 'test', version: '1.0.0' });
+  await client.connect(transport);
+  await client.ping();
+});
+
+test('sse transport browser lifecycle (isolated)', async ({ serverEndpoint, server }) => {
+  const { url, stderr } = await serverEndpoint({ args: ['--isolated'] });
+
+  const transport1 = new SSEClientTransport(url);
+  const client1 = new Client({ name: 'test', version: '1.0.0' });
+  await client1.connect(transport1);
+  await client1.callTool({
+    name: 'browser_navigate',
+    arguments: { url: server.HELLO_WORLD },
+  });
+  await client1.close();
+
+  const transport2 = new SSEClientTransport(url);
+  const client2 = new Client({ name: 'test', version: '1.0.0' });
+  await client2.connect(transport2);
+  await client2.callTool({
+    name: 'browser_navigate',
+    arguments: { url: server.HELLO_WORLD },
+  });
+  await client2.close();
+
+  await expect(async () => {
+    const lines = stderr().split('\n');
+    expect(lines.filter(line => line.match(/create SSE session/)).length).toBe(2);
+    expect(lines.filter(line => line.match(/delete SSE session/)).length).toBe(2);
+
+    expect(lines.filter(line => line.match(/create context/)).length).toBe(2);
+    expect(lines.filter(line => line.match(/close context/)).length).toBe(2);
+
+    expect(lines.filter(line => line.match(/create browser context \(isolated\)/)).length).toBe(2);
+    expect(lines.filter(line => line.match(/close browser context \(isolated\)/)).length).toBe(2);
+
+    expect(lines.filter(line => line.match(/obtain browser \(isolated\)/)).length).toBe(2);
+    expect(lines.filter(line => line.match(/close browser \(isolated\)/)).length).toBe(2);
+  }).toPass();
+});
+
+test('sse transport browser lifecycle (isolated, multiclient)', async ({ serverEndpoint, server }) => {
+  const { url, stderr } = await serverEndpoint({ args: ['--isolated'] });
+
+  const transport1 = new SSEClientTransport(url);
+  const client1 = new Client({ name: 'test', version: '1.0.0' });
+  await client1.connect(transport1);
+  await client1.callTool({
+    name: 'browser_navigate',
+    arguments: { url: server.HELLO_WORLD },
+  });
+
+  const transport2 = new SSEClientTransport(url);
+  const client2 = new Client({ name: 'test', version: '1.0.0' });
+  await client2.connect(transport2);
+  await client2.callTool({
+    name: 'browser_navigate',
+    arguments: { url: server.HELLO_WORLD },
+  });
+  await client1.close();
+
+  const transport3 = new SSEClientTransport(url);
+  const client3 = new Client({ name: 'test', version: '1.0.0' });
+  await client3.connect(transport3);
+  await client3.callTool({
+    name: 'browser_navigate',
+    arguments: { url: server.HELLO_WORLD },
+  });
+
+  await client2.close();
+  await client3.close();
+
+  await expect(async () => {
+    const lines = stderr().split('\n');
+    expect(lines.filter(line => line.match(/create SSE session/)).length).toBe(3);
+    expect(lines.filter(line => line.match(/delete SSE session/)).length).toBe(3);
+
+    expect(lines.filter(line => line.match(/create context/)).length).toBe(3);
+    expect(lines.filter(line => line.match(/close context/)).length).toBe(3);
+
+    expect(lines.filter(line => line.match(/create browser context \(isolated\)/)).length).toBe(3);
+    expect(lines.filter(line => line.match(/close browser context \(isolated\)/)).length).toBe(3);
+
+    expect(lines.filter(line => line.match(/obtain browser \(isolated\)/)).length).toBe(1);
+    expect(lines.filter(line => line.match(/close browser \(isolated\)/)).length).toBe(1);
+  }).toPass();
+});
+
+test('sse transport browser lifecycle (persistent)', async ({ serverEndpoint, server }) => {
+  const { url, stderr } = await serverEndpoint();
+
+  const transport1 = new SSEClientTransport(url);
+  const client1 = new Client({ name: 'test', version: '1.0.0' });
+  await client1.connect(transport1);
+  await client1.callTool({
+    name: 'browser_navigate',
+    arguments: { url: server.HELLO_WORLD },
+  });
+  await client1.close();
+
+  const transport2 = new SSEClientTransport(url);
+  const client2 = new Client({ name: 'test', version: '1.0.0' });
+  await client2.connect(transport2);
+  await client2.callTool({
+    name: 'browser_navigate',
+    arguments: { url: server.HELLO_WORLD },
+  });
+  await client2.close();
+
+  await expect(async () => {
+    const lines = stderr().split('\n');
+    expect(lines.filter(line => line.match(/create SSE session/)).length).toBe(2);
+    expect(lines.filter(line => line.match(/delete SSE session/)).length).toBe(2);
+
+    expect(lines.filter(line => line.match(/create context/)).length).toBe(2);
+    expect(lines.filter(line => line.match(/close context/)).length).toBe(2);
+
+    expect(lines.filter(line => line.match(/create browser context \(persistent\)/)).length).toBe(2);
+    expect(lines.filter(line => line.match(/close browser context \(persistent\)/)).length).toBe(2);
+
+    expect(lines.filter(line => line.match(/lock user data dir/)).length).toBe(2);
+    expect(lines.filter(line => line.match(/release user data dir/)).length).toBe(2);
+  }).toPass();
+});
+
+test('sse transport browser lifecycle (persistent, multiclient)', async ({ serverEndpoint, server }) => {
+  const { url } = await serverEndpoint();
+
+  const transport1 = new SSEClientTransport(url);
+  const client1 = new Client({ name: 'test', version: '1.0.0' });
+  await client1.connect(transport1);
+  await client1.callTool({
+    name: 'browser_navigate',
+    arguments: { url: server.HELLO_WORLD },
+  });
+
+  const transport2 = new SSEClientTransport(url);
+  const client2 = new Client({ name: 'test', version: '1.0.0' });
+  await client2.connect(transport2);
+  const response = await client2.callTool({
+    name: 'browser_navigate',
+    arguments: { url: server.HELLO_WORLD },
+  });
+  expect(response.isError).toBe(true);
+  expect(response.content?.[0].text).toContain('use --isolated to run multiple instances of the same browser');
+
+  await client1.close();
+  await client2.close();
+});
+
 test('streamable http transport', async ({ serverEndpoint }) => {
-  const transport = new StreamableHTTPClientTransport(new URL('/mcp', serverEndpoint));
+  const { url } = await serverEndpoint();
+  const transport = new StreamableHTTPClientTransport(new URL('/mcp', url));
   const client = new Client({ name: 'test', version: '1.0.0' });
   await client.connect(transport);
   await client.ping();
   expect(transport.sessionId, 'has session support').toBeDefined();
 });
-
-test('sse transport via public API', async ({ server }, testInfo) => {
-  const userDataDir = testInfo.outputPath('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: {
-          userDataDir,
-          launchOptions: { headless: true }
-        },
-      });
-      const transport = new SSEServerTransport('/sse', res);
-      sessions.set(transport.sessionId, transport);
-      await connection.connect(transport);
-    } else if (req.method === 'POST') {
-      const url = new URL(`http://localhost${req.url}`);
-      const sessionId = url.searchParams.get('sessionId');
-      if (!sessionId) {
-        res.statusCode = 400;
-        return res.end('Missing sessionId');
-      }
-      const transport = sessions.get(sessionId);
-      if (!transport) {
-        res.statusCode = 404;
-        return res.end('Session not found');
-      }
-      void transport.handlePostMessage(req, res);
-    }
-  });
-  await new Promise<void>(resolve => mcpServer.listen(0, () => resolve()));
-  const serverUrl = `http://localhost:${(mcpServer.address() as AddressInfo).port}/sse`;
-  const transport = new SSEClientTransport(new URL(serverUrl));
-  const client = new Client({ name: 'test', version: '1.0.0' });
-  await client.connect(transport);
-  await client.ping();
-  expect(await client.callTool({
-    name: 'browser_navigate',
-    arguments: { url: server.HELLO_WORLD },
-  })).toContainTextContent(`- generic [ref=e1]: Hello, world!`);
-  await client.close();
-  mcpServer.close();
-});

tests/tabs.spec.ts

@@ -141,7 +141,7 @@ test('reuse first tab when navigating', async ({ startClient, cdpServer, server
   const browserContext = await cdpServer.start();
   const pages = browserContext.pages();
 
-  const client = await startClient({ args: [`--cdp-endpoint=${cdpServer.endpoint}`] });
+  const { client } = await startClient({ args: [`--cdp-endpoint=${cdpServer.endpoint}`] });
   await client.callTool({
     name: 'browser_navigate',
     arguments: { url: server.HELLO_WORLD },

tests/trace.spec.ts

@@ -22,7 +22,7 @@ import { test, expect } from './fixtures.js';
 test('check that trace is saved', async ({ startClient, server }, testInfo) => {
   const outputDir = testInfo.outputPath('output');
 
-  const client = await startClient({
+  const { client } = await startClient({
     args: ['--save-trace', `--output-dir=${outputDir}`],
   });