Claude Browser MCP

Connects your Chrome browser to Claude (Cowork / Claude Code) via the MCP protocol. Claude can navigate, click, type, take screenshots, read pages, monitor network traffic, and control tabs — all from a conversation.

Claude ←── stdio MCP ──→ server.py ←── WebSocket :9009 ──→ Chrome Extension
                                                              └── browser APIs

Quick start

1 · Install Python dependencies

cd browser-mcp/server
pip install -r requirements.txt

2 · Load the Chrome extension

Open Chrome and go to chrome://extensions
Enable Developer mode (top-right toggle)
Click Load unpacked
Select the browser-mcp/extension folder
You'll see the ⚡ Claude Browser MCP icon in your toolbar

3 · Register the MCP server with Claude

Claude Code (CLI)

claude mcp add browser python3 /absolute/path/to/browser-mcp/server/server.py

Or add manually to ~/.claude.json (or your project's .claude/mcp_servers.json):

{
  "mcpServers": {
    "browser": {
      "command": "python3",
      "args": ["/absolute/path/to/browser-mcp/server/server.py"]
    }
  }
}

Claude Desktop

Edit ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "browser": {
      "command": "python3",
      "args": ["/absolute/path/to/browser-mcp/server/server.py"]
    }
  }
}

Then restart Claude Desktop.

4 · Start a session

Claude starts server.py automatically when you open a chat. Click the ⚡ extension icon — it should show Connected (green).

Available MCP tools

| Tool | What it does | |---|---| | navigate(url) | Go to a URL, waits for load | | go_back / go_forward | Browser history navigation | | reload_page | Reload current tab | | get_page_info | URL + title of current tab | | get_page_text | Visible text of the page (clean) | | get_page_html | Full HTML source (truncated at 50 k) | | take_screenshot | PNG screenshot Claude can see | | find_elements(selector) | Find DOM elements by CSS selector | | get_element_text(selector) | Read an element's text | | get_element_attribute(selector, attr) | Read an HTML attribute | | click_element(selector) | Click an element | | type_text(selector, text) | Type into an input / textarea | | wait_for_element(selector) | Wait for dynamic content | | scroll_page(direction) | up / down / top / bottom | | execute_javascript(code) | Run JS on the page | | list_tabs | All open tabs with IDs | | switch_tab(tab_id) | Focus a tab | | new_tab(url?) | Open a new tab | | close_tab(tab_id) | Close a tab | | duplicate_tab | Duplicate current or given tab | | get_network_requests | Recent XHR / fetch / resources | | get_console_logs | console.log / warn / error messages | | clear_network_requests | Clear captured requests | | clear_console_logs | Clear captured logs |

Example prompts

Go to github.com, find the search box, type "MCP server", and press enter.

Take a screenshot of the current page and tell me what you see.

Open a new tab, navigate to news.ycombinator.com, and summarise the top 5 stories.

Click the "Sign in" button and fill in the email field with test@example.com.

Check the browser console for any JavaScript errors on this page.

Notes

Debugger banner — Chrome shows "DevTools is debugging Chrome" while the extension is attached. This is required for network and console monitoring. It disappears when you close all Chrome windows.
Port — The WebSocket bridge uses localhost:9009. Change WS_PORT in both background.js and server.py if you need a different port.
Service worker lifetime — Chrome MV3 service workers can sleep after ~30 s of inactivity. The extension uses chrome.alarms to wake itself every ~24 s and reconnect automatically.
Security — The server only accepts connections from localhost. Do not expose port 9009 to the network.

Project layout

browser-mcp/
├── extension/
│   ├── manifest.json     Chrome extension manifest (MV3)
│   ├── background.js     Service worker — WebSocket bridge + all commands
│   ├── popup.html        Status UI shown when clicking the toolbar icon
│   └── popup.js          Reads connection state from chrome.storage
└── server/
    ├── server.py         Python MCP server (FastMCP + WebSocket bridge)
    └── requirements.txt  mcp[cli], websockets

MCP Servers