Chrome MCP Devtools

Chrome MCP DevTools

Use this skill when Codex needs to drive or inspect a real Chrome session through Chrome DevTools MCP, especially in a WSL to Windows setup.

Startup Workflow

1. Check whether Chrome remote debugging is already reachable.

curl -s --max-time 1 http://127.0.0.1:19222/json/version

• If the response is non-empty, continue to MCP tool discovery.
• If the response is empty or times out, start Chrome from Windows and retry.

2. Start Windows Chrome with a short timeout and quick retries.

timeout 5 bash -lc '(cd /mnt/c && cmd.exe /c start "" "C:\Program Files\Google\Chrome\Application\chrome.exe" --remote-debugging-port=19222 --remote-debugging-address=0.0.0.0 --user-data-dir="C:\tmp\chrome-debug-new" --remote-allow-origins="*") && for i in 1 2 3; do result=$(curl -s --max-time 1 http://127.0.0.1:19222/json/version 2>/dev/null); [ -n "$result" ] && echo "Connected at attempt $i" && break; [ $i -lt 3 ] && sleep 1; done; [ -n "$result" ] || echo "FAILED"'

• Keep the timeout short. Do not wait indefinitely.
• If this still fails, stop and report: 接続失敗: Chrome のデバッグポート http://127.0.0.1:19222/json/version に繋がりません。Chrome の起動状態を確認してください。

3. Discover the Chrome MCP tool namespace available in the current Codex environment.

• Look for tool names containing chrome-devtools, chrome_devtools, or both chrome and devtools.
• Do not promise browser actions until both conditions are true:
  • The debugging port responds.
  • The Chrome MCP tools are available in Codex.

4. Confirm control of the browser before doing deeper work.

• Prefer a non-destructive tool first:
  • page listing
  • screenshot
  • snapshot
• Report the current page or visible screen, then continue with the user's actual task.

Operating Rules

• Prefer immediate execution over asking for confirmation unless the environment explicitly requires approval.
• Prefer short retries over long passive waits.
• If multiple pages are open, list pages and select the correct one before clicking or typing.
• Before interacting with the DOM, capture a snapshot when the MCP toolset supports it.
• For UI debugging, inspect console messages and network requests after reproducing the issue.
• If the user asks only for connection setup, stop after confirming control with a screenshot or equivalent page state report.

Failure Handling

• If the debug port is closed after startup, treat it as a Chrome launch failure, not an MCP failure.
• If the debug port is open but MCP tools are missing, tell the user that Chrome DevTools MCP is not connected to Codex and cannot be used yet.
• If the default Windows Chrome path does not exist, report the expected path and adapt the launch command if the user provides a custom install location.
• If the environment is not WSL or not using Windows Chrome, adapt the launch step instead of forcing the Windows-specific command.

Common Triggers

• chromeMCP 使って
• Chrome DevTools MCP で見て
• ブラウザで確認して
• devtools で開いて調査して