MCP Server

Maintained

io.github.sh6drack/zen-mcp MCP Server

io.github.sh6drack/zen-mcp

Automate Zen Browser from Claude and Cursor using WebDriver BiDi—no Selenium, no Playwright.

What is the io.github.sh6drack/zen-mcp MCP server?

The zen-mcp MCP server enables automation of Zen Browser through WebDriver BiDi protocol, allowing Claude Code and Cursor to control browser tabs, navigate pages, fill forms, take screenshots, and execute JavaScript. It connects directly via WebSocket without requiring external browser drivers like Selenium or Playwright.

zen-mcp provides 20 tools for browser automation: navigate to URLs, manage tabs, capture screenshots, extract page content, interact with forms and elements, and run JavaScript. Use it to automate web tasks, test web applications, scrape content, or control Zen Browser from AI agents in Claude Code or Cursor.

How to install io.github.sh6drack/zen-mcp

Copy-paste configuration for popular MCP clients.

transport: stdio

Config generated by PluginBench — verify against the source before use.

Environment / auth

ZEN_DEBUG_PORT
Zen Browser remote debugging port

~/Library/Application Support/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "zen-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "zen-mcp"
      ],
      "env": {
        "ZEN_DEBUG_PORT": "<YOUR_ZEN_DEBUG_PORT>"
      }
    }
  }
}

Tools & capabilities

Tools this server exposes to the agent.

zen_navigate — Go to a URL
zen_list_pages — List all open tabs
zen_select_page — Switch to a tab
zen_new_tab — Open a new tab
zen_close_tab — Close a tab
zen_snapshot — Page structure with selectors (filter: all/interactive/form)
zen_screenshot — Capture a screenshot
zen_get_page_text — Get page title, URL, and text
zen_get_form_fields — List all form fields with labels and values
zen_click — Click an element
zen_fill — Type into an input or textarea
zen_select_option — Pick a dropdown option
zen_check — Toggle a checkbox or radio
zen_press_key — Keyboard input (Enter, Tab, Ctrl+A, etc.)
zen_fill_form — Fill multiple fields at once
zen_scroll — Scroll the page or to an element
zen_evaluate — Run JavaScript in the page
zen_wait — Wait N milliseconds
zen_wait_for — Wait for text or element to appear
zen_reconnect — Force reconnect to Zen

Use cases

Automate web form filling and data entry tasks from Claude Code
Test web applications by navigating pages, clicking elements, and capturing screenshots
Extract page content and text for web scraping or analysis
Control Zen Browser tabs and navigation programmatically from Cursor
Run JavaScript in web pages to interact with React, Vue, and Angular applications

io.github.sh6drack/zen-mcp MCP server FAQ

What is zen-mcp?

zen-mcp is an MCP server that automates Zen Browser using WebDriver BiDi protocol. It provides 20 tools for navigation, form filling, screenshots, and JavaScript execution, accessible from Claude Code and Cursor without needing Selenium or Playwright.

Is zen-mcp free?

Yes, zen-mcp is open-source under the MIT license and free to use.

How do I install zen-mcp in Claude Code?

Install via npm with `npm install -g zen-mcp`, then add it to `~/.claude/mcp_servers.json` with the command `zen-mcp`. Start Zen with `--remote-debugging-port 9222` first.

How do I install zen-mcp in Cursor?

The installation process is the same as Claude Code: install via npm, add to your MCP servers configuration, and start Zen with remote debugging enabled.

What are the requirements?

You need Zen Browser installed and Node.js 20 or higher. Start Zen with the `--remote-debugging-port 9222` flag to enable WebDriver BiDi.

What are the known limitations?

File uploads and drag-and-drop are not supported due to WebDriver BiDi spec limitations. Some advanced BiDi commands available in Chrome may not work in Firefox's implementation. Zombie sessions require restarting Zen.

README (reference)

Source of truth, from the repository.

zen-mcp

The first MCP server for Zen Browser. Automate Zen from Claude Code, Cursor, or any MCP client.

No Selenium. No Playwright. No browser drivers. Just WebSocket.

Setup (2 minutes)

1. Start Zen with remote debugging

/Applications/Zen.app/Contents/MacOS/zen --remote-debugging-port 9222

Pro tip: Add alias zen='open /Applications/Zen.app --args --remote-debugging-port 9222' to your shell config. Then just run zen.

2. Add to Claude Code

# Option A: npm (recommended)
npm install -g zen-mcp

# Option B: Clone
git clone https://github.com/sh6drack/zen-mcp.git && cd zen-mcp && npm install

Add to ~/.claude/mcp_servers.json:

{
  "mcpServers": {
    "zen-browser": {
      "command": "zen-mcp"
    }
  }
}

If you cloned instead of npm install, use "command": "node", "args": ["/absolute/path/to/zen-mcp/server.mjs"]

Add to ~/.claude/settings.json:

{
  "permissions": {
    "allow": ["mcp__zen-browser__*"]
  }
}

That's it. Start a new Claude Code session and the zen_* tools are available.

20 Tools

Browse

Tool	What it does
`zen_navigate`	Go to a URL
`zen_list_pages`	List all open tabs
`zen_select_page`	Switch to a tab
`zen_new_tab`	Open a new tab
`zen_close_tab`	Close a tab

See

Tool	What it does
`zen_snapshot`	Page structure with selectors (filter: all/interactive/form)
`zen_screenshot`	Capture a screenshot
`zen_get_page_text`	Get page title, URL, and text
`zen_get_form_fields`	List all form fields with labels and values

Interact

Tool	What it does
`zen_click`	Click an element
`zen_fill`	Type into an input or textarea
`zen_select_option`	Pick a dropdown option
`zen_check`	Toggle a checkbox or radio
`zen_press_key`	Keyboard input (Enter, Tab, Ctrl+A, etc.)
`zen_fill_form`	Fill multiple fields at once
`zen_scroll`	Scroll the page or to an element

Utility

Tool	What it does
`zen_evaluate`	Run JavaScript in the page
`zen_wait`	Wait N milliseconds
`zen_wait_for`	Wait for text or element to appear
`zen_reconnect`	Force reconnect to Zen

How It Works

Claude Code  ──stdio/MCP──>  zen-mcp  ──WebSocket/BiDi──>  Zen Browser

zen-mcp speaks WebDriver BiDi (W3C standard) directly over WebSocket. Form filling uses native value setters with input/change event dispatch so React, Vue, and Angular apps work correctly.

What Works Well

Navigation, clicking, form filling — rock solid, handles React/Vue/Angular
Screenshots and page reads — reliable content extraction
Tab management — open, close, switch between tabs
JavaScript evaluation — run any code in the page context
Keyboard input — shortcuts, Enter, Tab, modifier combos

Known Limitations

Zen inherits Firefox's WebDriver BiDi implementation, which is still maturing. Some advanced BiDi commands that work in Chrome may not be available yet.
Zombie sessions can only be cleared by restarting Zen (BiDi session.end is connection-scoped). zen-mcp detects this and tells you what to do.
No file upload or drag-and-drop support (BiDi spec limitation).

Built-in Reliability

Auto-reconnect with exponential backoff if WebSocket drops
Zombie session recovery when a previous client crashed
Connection retry (3 attempts with backoff)
Clean shutdown on SIGINT/SIGTERM to prevent orphaned sessions

Troubleshooting

Problem	Fix
"Cannot connect to Zen Browser"	Start Zen with `--remote-debugging-port 9222`
"Maximum number of active sessions"	Restart Zen: `killall zen && zen`
Connection keeps dropping	Use `zen_reconnect` to force a fresh connection

Config

Env Variable	Default	Description
`ZEN_DEBUG_PORT`	`9222`	Zen's remote debugging port

Requirements

Zen Browser
Node.js 20+

Test

node test-e2e.mjs   # 21 tests, needs Zen running

License

MIT

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io.github.sh6drack/zen-mcp MCP Server

What is the io.github.sh6drack/zen-mcp MCP server?

How to install io.github.sh6drack/zen-mcp

Tools & capabilities

Use cases

io.github.sh6drack/zen-mcp MCP server FAQ

zen-mcp

Setup (2 minutes)

1. Start Zen with remote debugging

2. Add to Claude Code

20 Tools

Browse

See

Interact

Utility

How It Works

What Works Well

Known Limitations

Built-in Reliability

Troubleshooting

Config

Requirements

Test

License

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