Chrome Extension Bridge MCP

What is Chrome Extension Bridge MCP?

A Chrome extension that creates a WebSocket connection between web pages and a local MCP server, enabling interaction with browser resources and execution of JavaScript functions from the server.

How to use Chrome Extension Bridge MCP?

Install dependencies with npm install, build with npm run debug, load the unpacked extension from the extension folder in Chrome’s developer mode. The extension automatically connects to ws://localhost:54319. On the server side, use the Client class to call tools and resources via the extension.

Key features of Chrome Extension Bridge MCP

• WebSocket bridge between pages and a local MCP server
• Access browser APIs, DOM, and global objects
• Execute JavaScript functions in the context of any web page
• Retrieve resources like user agent from the browser
• Simple JSON‑RPC‑like protocol for requests and responses
• Supports custom tools and resources defined on the server

Use cases of Chrome Extension Bridge MCP

• Control a web‑based editor (e.g., Three.js Editor) via window.editor
• Automate browser testing by calling native APIs from an MCP server
• Extract page content or metadata using resource endpoints
• Integrate web‑page interactions into AI‑powered workflows

FAQ from Chrome Extension Bridge MCP

What does this extension do differently from a standard MCP server?

It enables an MCP server to directly interact with live web pages by injecting a client script that communicates over WebSocket with the server.

What are the runtime requirements?

Node.js, the MCP SDK, and a Chrome browser (with developer mode enabled for the extension).

How do I change the WebSocket port?

Modify the port in extension/content.js and ensure it matches the port used by the Client instance on the server side.

Can I access any JavaScript object on a page?

Yes, the extension can execute arbitrary JavaScript in the context of the page, so any object accessible via window or the global scope can be reached.

Is authentication or encryption supported?

No authentication or encryption is mentioned. Connections are plain WebSocket to localhost and are intended for local development use only.