Browser Control

Open Firefox and navigate to the Browser Control MCP add-on page on addons.mozilla.org. Click 'Add to Firefox' and confirm the permissions. Alternatively, for development, go to about:debugging > This Firefox > Load Temporary Add-on and select the manifest.json from the firefox-extension folder of the cloned repository.

https://addons.mozilla.org/en-US/firefox/addon/browser-control-mcp/

After installing the extension, open the Firefox add-on preferences (or the extension's popup) to find the generated EXTENSION_SECRET value. Copy this string — you will need it in your MCP client configuration to authenticate the server.

Add the server to your Claude Desktop (or other MCP client) configuration file, passing the EXTENSION_SECRET and optional port via environment variables. The default port is 8089.

{
  "mcpServers": {
    "browser-control": {
      "command": "npx",
      "args": ["browser-control-mcp"],
      "env": {
        "EXTENSION_SECRET": "<your-secret-from-extension-prefs>",
        "EXTENSION_PORT": "8089"
      }
    }
  }
}

Restart your MCP client application. The server will start automatically and attempt to connect to the Firefox extension on the configured port. Open Firefox with at least one tab loaded, then ask Claude to list your open tabs to confirm the integration is working.

Tools that read webpage text content or highlight text require explicit user consent each time. When you ask Claude to read a page, Firefox will prompt you to allow the extension to access that page's content. Approve to let the tool proceed.