zen-mcp is the first MCP server for Zen Browser, providing 20 tools that let users automate Zen Browser from Claude Code, Cursor, or any MCP client. It does not rely on Selenium, Playwright, or browser drivers, and directly uses the WebDriver BiDi (W3C standard) protocol over WebSocket.
Main use Used to drive Zen Browser in an MCP client and complete browser automation tasks, such as page navigation, clicking, form filling, screenshots, page reading, tab management, and JavaScript execution.
Main capabilities
- Navigation, clicking, and form filling: relatively stable, can handle React, Vue, and Angular applications. Form filling uses the native value setter and dispatches input / change events.
- Screenshots and page reading: reliable content extraction.
- Tab management: open, close, and switch tabs.
- JavaScript execution: run arbitrary code in the page context.
- Keyboard input: supports shortcuts, Enter, Tab, and modifier key combinations.
How to use
- Start Zen with remote debugging: in your shell configuration you can add the alias zen='open /Applications/Zen.app --args --remote-debugging-port 9222', then run zen directly.
- Add to Claude Code: configure it in ~/.claude/mcp_servers.json; if cloning from source instead of npm install, use "command": "node", "args": ["/absolute/path/to/zen-mcp/server.mjs"]. Also add the corresponding configuration in ~/.claude/settings.json.
- After starting a new Claude Code session, you can use the zen_* tools.
Built-in reliability
- Automatic reconnection with exponential backoff when the WebSocket disconnects.
- Zombie session recovery after the previous client crashes.
- Connection retries (up to 3 times, with backoff).
- On receiving SIGINT/SIGTERM, cleanshutdown to prevent orphaned sessions.
Known limitations
- Zen inherits Firefox's WebDriver BiDi implementation, which is still maturing, and some advanced BiDi commands available in Chrome may not yet be available.
- Zombie sessions can only be cleared by restarting Zen (BiDi's session.end is connection-scoped); zen-mcp will detect this situation and indicate how to handle it.
- File upload and drag-and-drop are not supported (limited by the BiDi specification).
Information about fees, pricing, platform support scope, specific performance results, etc. is not yet provided.
