chrome-profile-mcp

Drive your real Chrome profiles (with existing logins, cookies, sessions) from Claude Code via @playwright/mcp --extension + the Playwright Chrome Extension relay.

Why this exists

Upstream @playwright/mcp --extension auto-discovers which Chrome profile to open — Default first, then numeric Profile N, preferring last_used — with no knob to pin a specific profile. If the browser extension is installed in several profiles, the relay tab can land in the wrong one (e.g. Diana's instead of jamu's).

This repo adds one env var, PLAYWRIGHT_MCP_PROFILE_DIRECTORY, via a small idempotent patch script, so each MCP server deterministically opens its own profile.

No extension code is modified. No credentials or tokens are stored here.

Related MCP server: browser-mcp-cdp

How it works

1. npm ci installs pinned @playwright/mcp@0.0.80 (which pulls playwright-core).

2. npm run postinstall runs patch-profile-directory.mjs, which rewrites one line in node_modules/playwright-core/lib/coreBundle.js (createExtensionBrowser):

// before (upstream)
const profileDirectory = userDataDir ? await findPlaywrightExtensionProfile(userDataDir) : void 0;
// after (patched)
const profileDirectory = process.env.PLAYWRIGHT_MCP_PROFILE_DIRECTORY ?? (userDataDir ? await findPlaywrightExtensionProfile(userDataDir) : void 0); // PATCHED

3. Each MCP server runs the vendored CLI with its own token + profile:

{
  "mcpServers": {
    "mcp-jamu": {
      "type": "stdio",
      "command": "node",
      "args": ["<repo>/node_modules/@playwright/mcp/cli.js", "--extension"],
      "env": {
        "PLAYWRIGHT_MCP_EXTENSION_TOKEN": "<token-from-that-profile>",
        "PLAYWRIGHT_MCP_PROFILE_DIRECTORY": "Profile 5"
      }
    }
  }
}

The token must equal that profile's extension localStorage auth-token (open chrome-extension://mmlmfjhmonkocbjadbfplnigmagldckm/connect.html in the target profile to view/regenerate it). Matching token → silent auto-connect; mismatch → Invalid token provided.; no token → manual tab picker.

Setup

git clone <this-repo> ~/.chrome-mcp/extension-servers   # or anywhere
cd ~/.chrome-mcp/extension-servers
npm ci          # installs + patches (postinstall)
node patch-profile-directory.mjs   # re-run any time node_modules is reinstalled

Requirements: Google Chrome (stable channel path), Playwright Extension installed in each target profile, @playwright/mcp@0.0.80 (pinned; the patch anchors to this bundle layout and fails loudly otherwise).

Constraints / gotchas

• Never set --user-data-dir to the live Chrome home — a second copy fights SingletonLock. With defaults (channel: chrome → ~/Library/Application Support/Google/Chrome on macOS) the relay attaches to the running Chrome session.

• Never run two servers with the same/empty profile pin — each needs its own relay port + connect tab.

• One profile = one token. Never commit tokens — use .mcp.json env (local, gitignored by clients) or your process manager's secret store.

• Patch is version-pinned: bumping @playwright/mcp requires re-verifying the anchor strings in patch-profile-directory.mjs.

• Tools surface as browser_* (browser_navigate, browser_snapshot, …), not puppeteer_*.

Verify

# should print: Version 0.0.80
./node_modules/.bin/playwright-mcp --version
# should print the patched line
grep -n PLAYWRIGHT_MCP_PROFILE_DIRECTORY node_modules/playwright-core/lib/coreBundle.js

Then point an MCP client at the vendored CLI, call browser_navigate https://example.com, and confirm the visit lands in the pinned profile's History (copy the live History file first — Chrome locks it while running).

Files

License

MIT — patch script and docs. Upstream packages retain their own licenses (Apache-2.0).