code · pull · Apr 14, 2026 · Apr 13, 2026 · Apr 14, 2026 · Apr 14, 2026
diff --git a/packages/playwright-core/src/protocol/validator.ts b/packages/playwright-core/src/protocol/validator.ts
@@ -511,7 +511,6 @@ scheme.BrowserTypeLaunchParams = tObject({
   args: tOptional(tArray(tString)),
   ignoreAllDefaultArgs: tOptional(tBoolean),
   ignoreDefaultArgs: tOptional(tArray(tString)),
-  assistantMode: tOptional(tBoolean),
   handleSIGINT: tOptional(tBoolean),
   handleSIGTERM: tOptional(tBoolean),
   handleSIGHUP: tOptional(tBoolean),
@@ -541,7 +540,6 @@ scheme.BrowserTypeLaunchPersistentContextParams = tObject({
   args: tOptional(tArray(tString)),
   ignoreAllDefaultArgs: tOptional(tBoolean),
   ignoreDefaultArgs: tOptional(tArray(tString)),
-  assistantMode: tOptional(tBoolean),
   handleSIGINT: tOptional(tBoolean),
   handleSIGTERM: tOptional(tBoolean),
   handleSIGHUP: tOptional(tBoolean),

diff --git a/packages/playwright-core/src/server/android/android.ts b/packages/playwright-core/src/server/android/android.ts
@@ -299,7 +299,7 @@ export class AndroidDevice extends SdkObject {
       '--disable-fre',
       '--no-default-browser-check',
       `--remote-debugging-socket-name=${socketName}`,
-      ...chromiumSwitches(undefined, undefined, true),
+      ...chromiumSwitches({ android: true }),
       ...this._innerDefaultArgs(options)
     ];
     return chromeArguments;

diff --git a/packages/playwright-core/src/server/bidi/bidiChromium.ts b/packages/playwright-core/src/server/bidi/bidiChromium.ts
@@ -102,7 +102,7 @@ export class BidiChromium extends BrowserType {
   }
 
   override async waitForReadyState(options: types.LaunchOptions, browserLogsCollector: RecentLogsCollector): Promise<{ wsEndpoint?: string }> {
-    return waitForReadyState({ ...options, cdpPort: 0 }, browserLogsCollector);
+    return waitForReadyState({ ...options, args: ['--remote-debugging-port=0'] }, browserLogsCollector);
   }
 
   private _innerDefaultArgs(options: types.LaunchOptions): string[] {
@@ -114,7 +114,7 @@ export class BidiChromium extends BrowserType {
       throw new Error('Playwright manages remote debugging connection itself.');
     if (args.find(arg => !arg.startsWith('-')))
       throw new Error('Arguments can not specify page to be opened');
-    const chromeArguments = [...chromiumSwitches(options.assistantMode)];
+    const chromeArguments = [...chromiumSwitches()];
 
     if (os.platform() === 'darwin') {
       // See https://issues.chromium.org/issues/40277080

diff --git a/packages/playwright-core/src/server/browser.ts b/packages/playwright-core/src/server/browser.ts
@@ -59,7 +59,7 @@ export type BrowserOptions = {
   protocolLogger: types.ProtocolLogger,
   browserLogsCollector: RecentLogsCollector,
   slowMo?: number;
-  wsEndpoint?: string;  // Only there when connected over web socket.
+  wsEndpoint?: string;
   sdkLanguage?: Language;
   originalLaunchOptions: types.LaunchOptions;
   userDataDir?: string;

diff --git a/packages/playwright-core/src/server/browserType.ts b/packages/playwright-core/src/server/browserType.ts
@@ -72,7 +72,7 @@ export abstract class BrowserType extends SdkObject {
     return this._innerLaunchWithRetries(progress, options, undefined, helper.debugProtocolLogger(protocolLogger)).catch(e => { throw this._rewriteStartupLog(e); });
   }
 
-  async launchPersistentContext(progress: Progress, userDataDir: string, options: channels.BrowserTypeLaunchPersistentContextOptions & { cdpPort?: number, internalIgnoreHTTPSErrors?: boolean, socksProxyPort?: number }): Promise<BrowserContext> {
+  async launchPersistentContext(progress: Progress, userDataDir: string, options: channels.BrowserTypeLaunchPersistentContextOptions & { internalIgnoreHTTPSErrors?: boolean, socksProxyPort?: number }): Promise<BrowserContext> {
     const launchOptions = this._validateLaunchOptions(options);
     // Note: Any initial TLS requests will fail since we rely on the Page/Frames initialize which sets ignoreHTTPSErrors.
     let clientCertificatesProxy: ClientCertificatesProxy | undefined;
@@ -109,7 +109,7 @@ export abstract class BrowserType extends SdkObject {
   private async _innerLaunch(progress: Progress, options: types.LaunchOptions, persistent: types.BrowserContextOptions | undefined, protocolLogger: types.ProtocolLogger, maybeUserDataDir?: string): Promise<Browser> {
     options.proxy = options.proxy ? normalizeProxySettings(options.proxy) : undefined;
     const browserLogsCollector = new RecentLogsCollector();
-    const { browserProcess, userDataDir, artifactsDir, transport } = await this._launchProcess(progress, options, !!persistent, browserLogsCollector, maybeUserDataDir);
+    const { browserProcess, userDataDir, artifactsDir, transport, wsEndpoint } = await this._launchProcess(progress, options, !!persistent, browserLogsCollector, maybeUserDataDir);
     try {
       if ((options as any).__testHookBeforeCreateBrowser)
         await progress.race((options as any).__testHookBeforeCreateBrowser());
@@ -128,7 +128,7 @@ export abstract class BrowserType extends SdkObject {
         proxy: options.proxy,
         protocolLogger,
         browserLogsCollector,
-        wsEndpoint: transport instanceof WebSocketTransport ? transport.wsEndpoint : undefined,
+        wsEndpoint,
         originalLaunchOptions: options,
         userDataDir: persistent ? userDataDir : undefined,
       };
@@ -198,7 +198,7 @@ export abstract class BrowserType extends SdkObject {
     return { executable, browserArguments, userDataDir, artifactsDir, tempDirectories };
   }
 
-  private async _launchProcess(progress: Progress, options: types.LaunchOptions, isPersistent: boolean, browserLogsCollector: RecentLogsCollector, userDataDir?: string): Promise<{ browserProcess: BrowserProcess, artifactsDir: string, userDataDir: string, transport: ConnectionTransport }> {
+  private async _launchProcess(progress: Progress, options: types.LaunchOptions, isPersistent: boolean, browserLogsCollector: RecentLogsCollector, userDataDir?: string): Promise<{ browserProcess: BrowserProcess, artifactsDir: string, userDataDir: string, transport: ConnectionTransport, wsEndpoint?: string }> {
     const {
       handleSIGINT = true,
       handleSIGTERM = true,
@@ -273,13 +273,13 @@ export abstract class BrowserType extends SdkObject {
         const updatedLog = this.doRewriteStartupLog(log);
         throw new Error(`Failed to launch the browser process.\nBrowser logs:\n${updatedLog}`);
       }
-      if (options.cdpPort !== undefined || !this.supportsPipeTransport()) {
+      if (!this.supportsPipeTransport()) {
         transport = await WebSocketTransport.connect(progress, wsEndpoint!);
       } else {
         const stdio = launchedProcess.stdio as unknown as [NodeJS.ReadableStream, NodeJS.WritableStream, NodeJS.WritableStream, NodeJS.WritableStream, NodeJS.ReadableStream];
         transport = new PipeTransport(stdio[3], stdio[4]);
       }
-      return { browserProcess, artifactsDir: prepared.artifactsDir, userDataDir: prepared.userDataDir, transport };
+      return { browserProcess, artifactsDir: prepared.artifactsDir, userDataDir: prepared.userDataDir, transport, wsEndpoint };
     } catch (error) {
       await progress.race(closeOrKill(DEFAULT_PLAYWRIGHT_TIMEOUT).catch(() => {}));
       throw error;

diff --git a/packages/playwright-core/src/server/chromium/chromium.ts b/packages/playwright-core/src/server/chromium/chromium.ts
@@ -74,7 +74,7 @@ export class Chromium extends BrowserType {
     return super.launch(progress, options, protocolLogger);
   }
 
-  override async launchPersistentContext(progress: Progress, userDataDir: string, options: channels.BrowserTypeLaunchPersistentContextOptions & { cdpPort?: number, internalIgnoreHTTPSErrors?: boolean, socksProxyPort?: number }): Promise<BrowserContext> {
+  override async launchPersistentContext(progress: Progress, userDataDir: string, options: channels.BrowserTypeLaunchPersistentContextOptions & { internalIgnoreHTTPSErrors?: boolean, socksProxyPort?: number }): Promise<BrowserContext> {
     if (options.channel?.startsWith('bidi-'))
       return this._bidiChromium.launchPersistentContext(progress, userDataDir, options);
     return super.launchPersistentContext(progress, userDataDir, options);
@@ -343,10 +343,7 @@ export class Chromium extends BrowserType {
   override async defaultArgs(options: types.LaunchOptions, isPersistent: boolean, userDataDir: string) {
     const chromeArguments = this._innerDefaultArgs(options);
     chromeArguments.push(`--user-data-dir=${userDataDir}`);
-    if (options.cdpPort !== undefined)
-      chromeArguments.push(`--remote-debugging-port=${options.cdpPort}`);
-    else
-      chromeArguments.push('--remote-debugging-pipe');
+    chromeArguments.push('--remote-debugging-pipe');
     if (isPersistent)
       chromeArguments.push('about:blank');
     else
@@ -363,7 +360,7 @@ export class Chromium extends BrowserType {
       throw new Error('Playwright manages remote debugging connection itself.');
     if (args.find(arg => !arg.startsWith('-')))
       throw new Error('Arguments can not specify page to be opened');
-    const chromeArguments = [...chromiumSwitches(options.assistantMode, options.channel)];
+    const chromeArguments = [...chromiumSwitches()];
 
     // See https://issues.chromium.org/issues/40277080
     chromeArguments.push('--enable-unsafe-swiftshader');
@@ -418,7 +415,7 @@ export class Chromium extends BrowserType {
 }
 
 export async function waitForReadyState(options: types.LaunchOptions, browserLogsCollector: RecentLogsCollector): Promise<{ wsEndpoint?: string }> {
-  if (options.cdpPort === undefined && !options.args?.some(a => a.startsWith('--remote-debugging-port')))
+  if (!options.args?.some(a => a.startsWith('--remote-debugging-port')))
     return {};
 
   const result = new ManualPromise<{ wsEndpoint?: string }>();

diff --git a/packages/playwright-core/src/server/chromium/chromiumSwitches.ts b/packages/playwright-core/src/server/chromium/chromiumSwitches.ts
@@ -17,7 +17,7 @@
 
 // No dependencies as it is used from the Electron loader.
 
-const disabledFeatures = (assistantMode?: boolean) => [
+const disabledFeatures = [
   // See https://github.com/microsoft/playwright/issues/14047
   'AvoidUnnecessaryBeforeUnloadCheckSync',
   // See https://github.com/microsoft/playwright/issues/38568
@@ -44,14 +44,13 @@ const disabledFeatures = (assistantMode?: boolean) => [
   'RenderDocument',
   // Prevents downloading optimization hints on startup.
   'OptimizationHints',
-  assistantMode ? 'AutomationControlled' : '',
   // Disables forced sign-in in Edge.
   'msForceBrowserSignIn',
   // Disables updating the preferred version in LaunchServices preferences on mac.
   'msEdgeUpdateLaunchServicesPreferredVersion',
 ].filter(Boolean);
 
-export const chromiumSwitches = (assistantMode?: boolean, channel?: string, android?: boolean) => [
+export const chromiumSwitches = (options?: { android?: boolean }) => [
   '--disable-field-trial-config', // https://source.chromium.org/chromium/chromium/src/+/main:testing/variations/README.md
   '--disable-background-networking',
   '--disable-background-timer-throttling',
@@ -66,7 +65,7 @@ export const chromiumSwitches = (assistantMode?: boolean, channel?: string, andr
   '--disable-dev-shm-usage',
   '--disable-edgeupdater', // Disables Edge-specific updater on mac.
   '--disable-extensions',
-  '--disable-features=' + disabledFeatures(assistantMode).join(','),
+  '--disable-features=' + disabledFeatures.join(','),
   process.env.PLAYWRIGHT_LEGACY_SCREENSHOT ? '' : '--enable-features=CDPScreenshotNewSurface',
   '--allow-pre-commit-input',
   '--disable-hang-monitor',
@@ -88,12 +87,11 @@ export const chromiumSwitches = (assistantMode?: boolean, channel?: string, andr
   '--unsafely-disable-devtools-self-xss-warnings',
   // Edge can potentially restart on Windows (msRelaunchNoCompatLayer) which looses its file descriptors (stdout/stderr) and CDP (3/4). Disable until fixed upstream.
   '--edge-skip-compat-layer-relaunch',
-  assistantMode ? '' : '--enable-automation',
   // This disables Chrome for Testing infobar that is visible in the persistent context.
   // The switch is ignored everywhere else, including Chromium/Chrome/Edge.
   '--disable-infobars',
   // Less annoying popups.
   '--disable-search-engine-choice-screen',
   // Prevents the "three dots" menu crash in IdentityManager::HasPrimaryAccount for ephemeral contexts.
-  android ? '' : '--disable-sync',
+  options?.android ? '' : '--disable-sync',
 ].filter(Boolean);
diff --git a/packages/playwright-core/src/server/firefox/firefox.ts b/packages/playwright-core/src/server/firefox/firefox.ts
@@ -47,7 +47,7 @@ export class Firefox extends BrowserType {
     return super.launch(progress, options, protocolLogger);
   }
 
-  override async launchPersistentContext(progress: Progress, userDataDir: string, options: channels.BrowserTypeLaunchPersistentContextOptions & { cdpPort?: number, internalIgnoreHTTPSErrors?: boolean, socksProxyPort?: number }): Promise<BrowserContext> {
+  override async launchPersistentContext(progress: Progress, userDataDir: string, options: channels.BrowserTypeLaunchPersistentContextOptions & { internalIgnoreHTTPSErrors?: boolean, socksProxyPort?: number }): Promise<BrowserContext> {
     if (options.channel?.startsWith('moz-'))
       return this._bidiFirefox.launchPersistentContext(progress, userDataDir, options);
     return super.launchPersistentContext(progress, userDataDir, options);

diff --git a/packages/playwright-core/src/server/recorder/recorderApp.ts b/packages/playwright-core/src/server/recorder/recorderApp.ts
@@ -214,7 +214,7 @@ export class RecorderApp {
       persistentContextOptions: {
         noDefaultViewport: true,
         headless: !!process.env.PWTEST_CLI_HEADLESS || (isUnderTest() && !headed),
-        cdpPort: isUnderTest() ? 0 : undefined,
+        args: isUnderTest() ? ['--remote-debugging-port=0'] : undefined,
         handleSIGINT: params.handleSIGINT,
         executablePath: isChromium ? inspectedContext._browser.options.customExecutablePath : undefined,
         // Use the same channel as the inspected context to guarantee that the browser is installed.

diff --git a/packages/playwright-core/src/server/trace/viewer/traceViewer.ts b/packages/playwright-core/src/server/trace/viewer/traceViewer.ts
@@ -178,7 +178,7 @@ export async function openTraceViewerApp(url: string, browserName: string, optio
     windowSize: { width: 1280, height: 800 },
     persistentContextOptions: {
       ...options?.persistentContextOptions,
-      cdpPort: isUnderTest() ? 0 : undefined,
+      args: isUnderTest() ? ['--remote-debugging-port=0'] : undefined,
       headless: !!options?.headless,
       colorScheme: isUnderTest() ? 'light' : undefined,
     },

diff --git a/packages/playwright-core/src/server/types.ts b/packages/playwright-core/src/server/types.ts
@@ -155,9 +155,7 @@ export type NormalizedContinueOverrides = {
 export type EmulatedSize = { viewport: Size, screen: Size };
 
 export type LaunchOptions = Omit<channels.BrowserTypeLaunchParams, 'timeout'> & {
-  cdpPort?: number,
   proxyOverride?: ProxySettings,
-  assistantMode?: boolean,
   socksProxyPort?: number,
 };
 

diff --git a/packages/playwright-core/src/serverRegistry.ts b/packages/playwright-core/src/serverRegistry.ts
@@ -75,7 +75,7 @@ class ServerRegistry {
       const entries = await Promise.all(promises);
       const descriptors = [];
       for (const entry of entries) {
-        if (!entry.canConnect && !entry.browser.userDataDir) {
+        if (!entry.canConnect) {
           await fs.promises.unlink(entry.file).catch(() => {});
           continue;
         }

diff --git a/packages/playwright-core/src/tools/cli-client/session.ts b/packages/playwright-core/src/tools/cli-client/session.ts
@@ -67,7 +67,7 @@ export class Session {
   }
 
   async deleteData() {
-    await this.stop();
+    await this.stop(true);
 
     const dataDirs = await fs.promises.readdir(this._sessionFile.daemonDir).catch(() => []);
     const matchingEntries = dataDirs.filter(file => file === `${this.name}.session` || file.startsWith(`ud-${this.name}-`));

diff --git a/packages/playwright-core/src/tools/mcp/browserFactory.ts b/packages/playwright-core/src/tools/mcp/browserFactory.ts
@@ -195,9 +195,10 @@ async function createUserDataDir(config: FullConfig, clientInfo: ClientInfo) {
 }
 
 async function injectCdpPort(browserConfig: FullConfig['browser']) {
-  if (browserConfig.browserName === 'chromium')
-    // eslint-disable-next-line no-restricted-syntax
-    (browserConfig.launchOptions as any).cdpPort = await findFreePort();
+  if (browserConfig.browserName === 'chromium') {
+    browserConfig.launchOptions.args = browserConfig.launchOptions.args ?? [];
+    browserConfig.launchOptions.args?.push(`--remote-debugging-port=${await findFreePort()}`);
+  }
 }
 
 async function findFreePort(): Promise<number> {

diff --git a/packages/playwright-core/src/tools/mcp/cdpRelay.ts b/packages/playwright-core/src/tools/mcp/cdpRelay.ts
@@ -22,8 +22,8 @@
  * - /extension/guid - Extension connection
  *
  * Protocol version is controlled by PLAYWRIGHT_EXTENSION_PROTOCOL env variable:
- * - v1: single-tab, extension manages debugger attachment
- * - v2 (default): multi-tab, relay manages debugger via chrome.* APIs
+ * - v1 (default): single-tab, extension manages debugger attachment
+ * - v2: multi-tab, relay manages debugger via chrome.* APIs
  */
 
 import { spawn } from 'child_process';
@@ -77,7 +77,7 @@ export class CDPRelayServer {
     this._browserChannel = browserChannel;
     this._userDataDir = userDataDir;
     this._executablePath = executablePath;
-    this._protocolVersion = parseInt(process.env.PLAYWRIGHT_EXTENSION_PROTOCOL ?? protocol.VERSION.toString(), 10);
+    this._protocolVersion = parseInt(process.env.PLAYWRIGHT_EXTENSION_PROTOCOL ?? protocol.DEFAULT_VERSION.toString(), 10);
 
     const sendCommand = (method: string, params: any): Promise<any> => {
       if (!this._extensionConnection)

diff --git a/packages/playwright-core/src/tools/mcp/config.ts b/packages/playwright-core/src/tools/mcp/config.ts
@@ -163,17 +163,18 @@ export async function resolveCLIConfigForCLI(daemonProfilesDir: string, sessionN
   if (result.browser.isolated === undefined)
     result.browser.isolated = !options.profile && !options.persistent && !result.browser.userDataDir && !result.browser.remoteEndpoint && !result.browser.cdpEndpoint && !result.extension;
 
-  if (!result.extension && !result.browser.isolated && !result.browser.userDataDir && !result.browser.remoteEndpoint && !result.browser.cdpEndpoint) {
-    // No custom value provided, use the daemon data dir.
-    const browserToken = result.browser.launchOptions?.channel ?? result.browser?.browserName;
-    const userDataDir = path.resolve(daemonProfilesDir, `ud-${sessionName}-${browserToken}`);
-    result.browser.userDataDir = userDataDir;
-  }
-
   if (result.browser.launchOptions.headless === undefined)
     result.browser.launchOptions.headless = true;
 
   const browser = await validateBrowserConfig(result.browser);
+
+  if (!result.extension && !browser.isolated && !browser.userDataDir && !browser.remoteEndpoint && !browser.cdpEndpoint) {
+    // No custom value provided, use the daemon data dir.
+    const browserToken = browser.launchOptions?.channel ?? browser?.browserName;
+    const userDataDir = path.resolve(daemonProfilesDir, `ud-${sessionName}-${browserToken}`);
+    browser.userDataDir = userDataDir;
+  }
+
   return { ...result, browser, configFile, skillMode: true };
 }
 
@@ -412,8 +413,6 @@ function mergeConfig(base: MergedConfig, overrides: Config): MergedConfig {
     launchOptions: {
       ...pickDefined(base.browser?.launchOptions),
       ...pickDefined(overrides.browser?.launchOptions),
-      // Assistant mode is not a part of the public API.
-      ...{ assistantMode: true },
     },
     contextOptions: {
       ...pickDefined(base.browser?.contextOptions),

diff --git a/packages/playwright-core/src/tools/mcp/protocol.ts b/packages/playwright-core/src/tools/mcp/protocol.ts
@@ -14,9 +14,14 @@
  * limitations under the License.
  */
 
-// Whenever the commands/events change, the version must be updated. The latest
-// extension version should be compatible with the old MCP clients.
-export const VERSION = 2;
+// The latest protocol version defined in this file. Bumped whenever the
+// commands/events change. The latest extension version should remain
+// compatible with older MCP clients.
+export const LATEST_VERSION = 2;
+
+// The protocol version used by default when PLAYWRIGHT_EXTENSION_PROTOCOL is
+// not set. May lag behind LATEST_VERSION while a new version is rolling out.
+export const DEFAULT_VERSION = 1;
 
 // Structural mirrors of @types/chrome shapes used over the wire. The extension
 // imports the real chrome.* types and they are structurally compatible.

diff --git a/packages/protocol/src/channels.d.ts b/packages/protocol/src/channels.d.ts
@@ -902,7 +902,6 @@ export type BrowserTypeLaunchParams = {
   args?: string[],
   ignoreAllDefaultArgs?: boolean,
   ignoreDefaultArgs?: string[],
-  assistantMode?: boolean,
   handleSIGINT?: boolean,
   handleSIGTERM?: boolean,
   handleSIGHUP?: boolean,
@@ -929,7 +928,6 @@ export type BrowserTypeLaunchOptions = {
   args?: string[],
   ignoreAllDefaultArgs?: boolean,
   ignoreDefaultArgs?: string[],
-  assistantMode?: boolean,
   handleSIGINT?: boolean,
   handleSIGTERM?: boolean,
   handleSIGHUP?: boolean,
@@ -958,7 +956,6 @@ export type BrowserTypeLaunchPersistentContextParams = {
   args?: string[],
   ignoreAllDefaultArgs?: boolean,
   ignoreDefaultArgs?: string[],
-  assistantMode?: boolean,
   handleSIGINT?: boolean,
   handleSIGTERM?: boolean,
   handleSIGHUP?: boolean,
@@ -1047,7 +1044,6 @@ export type BrowserTypeLaunchPersistentContextOptions = {
   args?: string[],
   ignoreAllDefaultArgs?: boolean,
   ignoreDefaultArgs?: string[],
-  assistantMode?: boolean,
   handleSIGINT?: boolean,
   handleSIGTERM?: boolean,
   handleSIGHUP?: boolean,

diff --git a/packages/protocol/src/protocol.yml b/packages/protocol/src/protocol.yml
@@ -491,7 +491,6 @@ LaunchOptions:
     ignoreDefaultArgs:
       type: array?
       items: string
-    assistantMode: boolean?
     handleSIGINT: boolean?
     handleSIGTERM: boolean?
     handleSIGHUP: boolean?