[Feature]: Support Chrome M144+ Remote Debugging via chrome://inspect/#remote-debugging

[qingqiuhe]

🚀 Feature Request

Playwright's connectOverCDP() cannot connect to Chrome browsers (M144+) that have remote debugging enabled via chrome://inspect/#remote-debugging. This new Chrome feature allows users to enable remote debugging on an already-running browser instance without needing to restart Chrome with --remote-debugging-port.

Background

Starting from Chrome M144, users can enable remote debugging on a running Chrome instance:

1. Navigate to chrome://inspect/#remote-debugging
2. Follow the dialog UI to allow incoming debugging connections
3. Chrome exposes a CDP endpoint (e.g., ws://127.0.0.1:9222/devtools/browser/<id>)

This is different from the traditional --remote-debugging-port approach:

• No need to restart Chrome
• Can enable debugging on-demand
• Uses a different internal protocol

Current Behavior

When attempting to connect to this type of endpoint:

const browser = await chromium.connectOverCDP('ws://127.0.0.1:9222/devtools/browser/<id>');

Playwright establishes the WebSocket connection successfully, but then times out waiting for expected protocol messages. The connection fails with:

Error: Timeout 30000ms exceeded.
Call log:
  - <ws connecting> ws://127.0.0.1:9222/devtools/browser/<id>
  - <ws connected> ws://127.0.0.1:9222/devtools/browser/<id>

Expected Behavior

Playwright should be able to connect to Chrome M144+ remote debugging endpoints, similar to how Puppeteer supports this via the handleDevToolsAsPage option.

Reference Implementation

Puppeteer (used by chrome-devtools-mcp) supports this through:

// Puppeteer's approach
await puppeteer.connect({
  browserWSEndpoint: 'ws://127.0.0.1:9222/devtools/browser/<id>',
  targetFilter: (target) => {
    // Filter targets appropriately
    return true;
  },
  defaultViewport: null,
  handleDevToolsAsPage: true,  // Key option for M144+ remote debugging
});

The handleDevToolsAsPage: true option enables Puppeteer to correctly handle the DevTools protocol variant used by Chrome M144+'s new remote debugging feature.

Use Cases

1. Debugging user's browser - Connect to a user's existing Chrome session for support/debugging without requiring them to restart with special flags
2. On-demand inspection - Enable remote debugging temporarily without disrupting the user's workflow
3. CI/CD environments - Some CI setups may prefer enabling debugging on existing browser instances
4. MCP servers / AI agents - AI coding assistants need to connect to user's existing browser for automation

Proposed Solution

Add a new option to connectOverCDP():

await chromium.connectOverCDP(endpointURL, {
  handleDevToolsAsPage: boolean,  // Support Chrome M144+ remote debugging
  timeout: number,
  headers: Record<string, string>,
});

Alternatively, detect the endpoint type automatically and handle both protocols transparently.

Environment

• Playwright version: v1.51.0
• Chrome version: M144+
• OS: All platforms

[Skn0tt]

Hi! It works just fine for me when using http://127.0.0.1:9222 as the connection string, without the path.

[Skn0tt]

Tried it again today, didn't work. Gotta investigate deeper.

[Skn0tt]

Depending on the browser config, /devtools/browser is required as the path.