Zen Mcp

io.github.sh6drackPublished by GitHub account sh6drackv1.2.1Updated Nov 3, 2026

MCP server for Zen Browser automation via WebDriver BiDi

VerifiedSTDIODesktop onlyWeb Search & ScrapingBrowser Automation

Overview

AI-generated overview

MCP server that lets an assistant drive the Zen Browser over WebDriver BiDi: navigate, read pages, click, fill forms, and take screenshots.

What you can do
  • Navigate and manage tabs: open a URL, list, select, open and close tabs
  • Inspect pages: structural snapshot with selectors, screenshots, page title/URL/text, form fields
  • Interact with elements: click, type into inputs, pick dropdown options, toggle checkboxes, press keys, fill several fields at once, scroll
  • Run utilities: execute JavaScript in the page, wait for a duration or for text/element to appear, force a reconnect
When to use it
Useful when an assistant should operate a real Zen Browser session on the user's desktop — browsing sites, reading page content, filling and submitting web forms, or checking UI behavior — without Selenium, Playwright or separate browser drivers.
Requirements
Zen Browser installed and started with remote debugging enabled on a port (default 9222, configurable via ZEN_DEBUG_PORT). Node.js 20+ and the zen-mcp npm package (or a local clone). Desktop only; the MCP client connects over stdio.
Before you install
The assistant can act inside the user's logged-in browser: clicking, typing, submitting forms and running arbitrary JavaScript in page context, which can change or send data on any site the browser is signed into. Remote debugging opens a local port that other local processes could also use. Some BiDi features are limited, and stuck sessions may require restarting Zen.

Installation

In SourceWeft

  1. Open Zen Mcp in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

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

bash
/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

bash
# Option A: npm (recommended)npm install -g zen-mcp
# Option B: Clonegit clone https://github.com/sh6drack/zen-mcp.git && cd zen-mcp && npm install

Add to ~/.claude/mcp_servers.json:

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:

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

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

20 Tools

Browse

ToolWhat it does
zen_navigateGo to a URL
zen_list_pagesList all open tabs
zen_select_pageSwitch to a tab
zen_new_tabOpen a new tab
zen_close_tabClose a tab

See

ToolWhat it does
zen_snapshotPage structure with selectors (filter: all/interactive/form)
zen_screenshotCapture a screenshot
zen_get_page_textGet page title, URL, and text
zen_get_form_fieldsList all form fields with labels and values

Interact

ToolWhat it does
zen_clickClick an element
zen_fillType into an input or textarea
zen_select_optionPick a dropdown option
zen_checkToggle a checkbox or radio
zen_press_keyKeyboard input (Enter, Tab, Ctrl+A, etc.)
zen_fill_formFill multiple fields at once
zen_scrollScroll the page or to an element

Utility

ToolWhat it does
zen_evaluateRun JavaScript in the page
zen_waitWait N milliseconds
zen_wait_forWait for text or element to appear
zen_reconnectForce 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

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

Config

Env VariableDefaultDescription
ZEN_DEBUG_PORT9222Zen's remote debugging port

Requirements

Test

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

License

MIT

Source: README.md at commit 76aa1e7

Tools

0
SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

1
  1. v1.2.1LatestSep 16, 2026

Score

40% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 days25 pts

    Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.

  • Auth declared10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts

    Declare a license in the repository or the registry entry.