domagent — MCP Server

The MCP (Model Context Protocol) server for DOMAgent. Lets AI agents control your real Chrome or Firefox browser through a local WebSocket bridge.

Install

npm install -g domagent

Or run without installing:

npx domagent

What it does

domagent is a local server that:

• Starts a WebSocket listener on ws://127.0.0.1:18792/extension
• Waits for the browser extension (Chrome or Firefox) to connect
• Exposes browser actions as MCP tools to any AI agent that supports the Model Context Protocol

The browser extension and the MCP server work together — the extension relays commands from the server into the real browser tab.

Requirements

• Node.js 18 or newer
• The DOMAgent browser extension installed in Chrome or Firefox
  → Chrome install guide
  → Firefox install guide

Configure your AI agent

Add domagent as an MCP server in your agent's config file.

Claude Desktop (claude_desktop_config.json)

{
  "mcpServers": {
    "domagent": {
      "command": "npx",
      "args": ["domagent"]
    }
  }
}

If you installed globally (npm install -g domagent):

{
  "mcpServers": {
    "domagent": {
      "command": "domagent"
    }
  }
}

Other MCP-compatible agents

Any agent that supports MCP stdio transport can use:

command: npx domagent
transport: stdio

Available MCP Tools

| Tool | Description | |------|-------------| | navigate | Open a URL — reuses the automation tab (no duplicate tabs) | | use_current_tab | Adopt the user's active tab — no new tab created | | click | Click an element by CSS selector | | type_text | Type into an input field by CSS selector | | get_text | Get the text content of an element | | evaluate_script | Execute arbitrary JavaScript in the page | | get_screenshot | Capture a PNG screenshot of the current page | | get_interactive_elements | List all interactive elements with selectors and bounding boxes | | clear_overlays | Remove all visual overlay boxes from the page |

Quick start (3 steps)

Step 1 — Start the MCP server:

npx domagent

You should see:

DOMAgent Bridge running on ws://127.0.0.1:18792/extension

Step 2 — Load the browser extension:

• Chrome: chrome://extensions → Developer mode → Load unpacked → select domagent-extension/chrome/
• Firefox: about:debugging → Load Temporary Add-on → select domagent-extension/firefox/manifest.json

Step 3 — Add to your AI agent config (see above) and start chatting.

Configuration

By default the server binds to 127.0.0.1:18792. To change this, edit the host/port/path in the browser extension's Options page (right-click the extension icon → Options).

The server accepts one WebSocket connection at a time — the browser extension.

Source

Full source, browser extensions, and documentation:
https://github.com/vaishnavucv/domagent