MCP Browser Kit

MCP Browser Kit

🚀 On the main branch? You're viewing the bleeding-edge dev docs! For other versions, check out the release/* branches.

An MCP Server that enables AI assistants to interact with your local browsers. It's an alternative to "Claude in Chrome" that works with any AI assistant or coding agent.

https://github.com/user-attachments/assets/1fbf87fd-06d1-42bf-a06f-cc2bbdf375a8

Usage

1. Add MCP Browser Kit to your MCP Client:

    {
        "mcpServers": {
            "browser-kit": {
                "command": "npx",
                "args": ["@mcp-browser-kit/server@latest"]
            }
        }
    }

   By default the server use stdio transport, alternatively you can use http transport:

    npx @mcp-browser-kit/server@latest --transport http
    # optional flags (defaults shown):
    #   --http-host 127.0.0.1
    #   --http-port 21082

   Then point your MCP client at the URL instead of a command:

    {
        "mcpServers": {
            "browser-kit": {
                "url": "http://127.0.0.1:21082/mcp"
            }
        }
    }

   Security: there's no auth yet, so --http-host defaults to 127.0.0.1 (loopback only). Only pass --http-host 0.0.0.0 (or a LAN address) if you understand that anyone who can reach that host/port can control your browser.

2. Choose the right extension build for your browser:
   • Check the Compatibility table below to see which build (M2 or M3) is compatible with your browser
   • Note that M2 builds offer more functionality than M3 builds, so prefer M2 if your browser supports both
3. Download the latest compatible build from The Latest Release.
4. Load the extension into a compatible browser and enable it.
5. Refresh open tabs to ensure extension scripts are loaded.
6. Start messaging on your MCP Client:

    Use browser-kit, star the last open GitHub repo on my browser

7. Optional, check User Notes for more information.

Compatibility table

The M2 build supports more functionalities than the M3 build. Extension file name patterns:

• M2 build:
  • Chromium: mcp_browser_kit_m2-<version>.zip (e.g., mcp_browser_kit_m2-5.0.0.zip)
  • Firefox: mcp_browser_kit_m2-<version>.xpi (e.g., mcp_browser_kit_m2-5.0.0.xpi)
• M3 build: mcp_browser_kit_m3-<version>.zip (e.g., mcp_browser_kit_m3-5.0.0.zip)

Load Extension

• Chromium-based browsers (Chrome, Brave, Edge)
  1. Unzip the downloaded .zip file
  2. Open chrome://extensions/
  3. Enable Developer mode
  4. Click Load unpacked
  5. Select the unpacked extension folder
• Firefox
  1. Open about:addons
  2. Click the gear icon and select Install Add-on From File
  3. Select the downloaded .xpi file
• Safari
  1. Unzip the downloaded .zip file
  2. Open Develop > Show Extension Builder
  3. Click + and select Add Extension
  4. Select the unpacked extension folder
  5. Click Install to install the extension

User Notes

Note for Alpha stage: Consider using a separate browser profile or dedicated browser instance with this MCP to prevent sensitive data from being unintentionally exposed to AI model providers.

Security: BrowserKit currently lacks authentication for incoming requests. Keep ports 21082 and 2769-2799 on your device network only.

Hosted deployment

A hosted deployment is available on Fronteir AI.