This project provides a framework for integrating AI agents with web applications by exposing website functionality as callable "tools" via the Model Context Protocol (MCP). It targets website owners who want to make their sites AI-ready and users who want to interact with websites using natural language through a browser extension. The primary benefit is enabling deterministic, secure AI interactions that leverage existing browser authentication and UI.

How It Works

MCP-B acts as an MCP server within the browser, using TabServerTransport for intra-tab communication and Chrome's runtime messaging for extension interaction. Website owners register tools (functions wrapping existing logic) with an McpServer instance. The MCP-B Chrome extension discovers these tools across open tabs and routes AI-generated requests to the appropriate website, executing the tool within the user's browser session. This approach leverages the browser's security model, avoiding the need for separate API keys or complex authentication setups for AI agents.

Quick Start & Requirements

• Install: Use the MCP-B Chrome Extension from the Chrome Web Store. For local development or integration, install @mcp-b/transports, @modelcontextprotocol/sdk, and zod via npm/pnpm.
• Prerequisites: Node.js 22.12+, pnpm 10+.
• Setup: Minimal setup for users via the extension. Local development requires cloning the repo and running pnpm install and pnpm dev.
• Links: Quick Start, Live Demo, Documentation

Highlighted Details

• Enables AI to call website functions directly using browser authentication.
• Tools can be dynamically registered and scoped to specific pages or user states.
• Supports a native server for bridging browser extensions to local AI clients (e.g., Claude Desktop).
• Examples include vanilla TypeScript and script tag integrations.

Maintenance & Community

The project is maintained by @miguelsPizza. Community contributions are welcome, focusing on transports, examples, or documentation. Contact: alexnahasdev@gmail.com.

Licensing & Compatibility

Licensed under the MIT license, permitting commercial use and integration with closed-source applications.

Limitations & Caveats

Currently, the browser extension is limited to Chrome. Firefox and Safari support are planned for future releases. Support for elicitation for sensitive operations is also noted as coming soon.