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chrome-browser

Use when setting up a dedicated Chrome browser for Playwright MCP with session persistence, or when encountering Cloudflare challenges during browser automation. Covers CDP setup, launchd auto-start, and persistent login sessions.

personAuthor: jakexiaohubgithub
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Dedicated Chrome Browser

A dedicated headed Chrome instance with CDP for Playwright MCP. Persistent profile (cookies/logins survive restarts), launchd-managed, multi-session safe.

Why

  • Chrome's single-instance lock prevents CDP when the default profile is in use — dedicated user-data-dir required
  • Headed so the user can log into sites manually; Playwright shares the session
  • launchd auto-starts on login, restarts on crash

Architecture

Chrome (dedicated CDP instance, port 9222)
  └── ~/.cache/chrome-cdp-profile (persistent, isolated from daily Chrome)
      ├── Claude session 1 → Playwright MCP → CDP
      ├── Claude session 2 → Playwright MCP → CDP
      └── User can log into sites manually (headed)

Quick Reference

# Check CDP
curl -s http://127.0.0.1:9222/json/version

# Configure Playwright MCP (user-scope, one-time)
claude mcp add -s user playwright -- npx @playwright/mcp --cdp-endpoint http://127.0.0.1:9222

# Manual launch (if not using launchd)
./launch-chrome-cdp.sh

Key Decisions

| Decision | Rationale | |----------|-----------| | Isolated profile (~/.cache/chrome-cdp-profile) | Avoids single-instance lock, doesn't interfere with daily browsing | | Direct binary launch | open -a unreliably passes --args; binary + disown is reliable | | Headed (not headless) | User can log into sites manually, cookies persist for automation | | launchd KeepAlive on crash only | Restart on crash, but intentional quit stays quit | | User-scope MCP (-s user) | Available across all projects |

Troubleshooting

  • Cloudflare challenges: If a site shows a Cloudflare challenge/waiting page, just wait — the browser MCP can usually handle it. We are very rarely actually blocked.
  • CDP not responding: Run launch-chrome-cdp.sh to start or check status.
  • Profile conflicts: If Chrome complains about profile lock, check for zombie Chrome processes: ps aux | grep chrome-cdp-profile

Setup

See INSTALL.md for the full setup checklist, including the launch script and launchd plist.

Self-Improvement

If you encounter a setup step that fails, a Chrome/Playwright behavior change, or missing guidance in this skill, don't just work around it — fix the skill:

  1. Create a PR from a fresh worktree of https://github.com/eins78/skills on a new branch, fixing the issue directly
  2. Or file an issue on https://github.com/eins78/skills with: what failed, the actual behavior, and the suggested fix

Never silently work around a skill gap. The fix benefits all future sessions.