@thuyphuocthinh/mcp-auth-proxy 🔐

Zero-config Stdio to Streamable HTTP MCP runtime proxy with automatic OAuth 2.0 PKCE discovery & silent token refresh.

mcp-auth-proxy acts as a zero-config bridge between your AI Client (Google Antigravity, Cursor, Windsurf, Claude Code, VS Code Copilot) and any remote Model Context Protocol (MCP) server protected by OAuth 2.0 (e.g., 200Lab AI Tutor, Notion, Linear, GitHub).

🌟 Highlights

• 🚀 Zero Runtime Dependencies: Pure Node.js (node:http, node:crypto, node:net), lightweight, launches immediately via npx.

• 🔍 Automated OAuth Discovery: Intercepts 401 Unauthorized, parses WWW-Authenticate: Bearer resource_metadata="..." and resolves .well-known endpoints automatically.

• 🔑 Dynamic Client Registration (RFC 7591) & PKCE (RFC 7636): Automatically registers client IDs on the fly with S256 challenge, eliminating the need for hardcoded client secrets.

• 🌐 Cross-Platform Auto Browser Launch: Automatically opens default browser on Windows (start), macOS (open), and Linux (xdg-open).

• 🔄 Silent Background Refresh: Automatically renews expiring tokens in the background via grant_type=refresh_token before the 5-minute expiry threshold.

• 🛡️ Static Header Bypass: Support for --header flag to pass static API keys or personal access tokens directly.

• 🚦 Dynamic Port Selection: Automatically scans for free local ports starting from 8080 (8081, 8082...), eliminating EADDRINUSE port collision errors.

Related MCP server: Cartena MCP Server

📦 Usage

1. Antigravity / Cursor Configuration

Add this entry to your mcp_config.json or claude_desktop_config.json:

{
  "mcpServers": {
    "200lab-ai-tutor": {
      "command": "npx",
      "args": [
        "-y",
        "@thuyphuocthinh/mcp-auth-proxy",
        "https://mcp.200lab.io/mcp/learner"
      ]
    }
  }
}

On first launch, your browser will automatically pop up to approve authorization. Subsequent launches will run silently forever with automatic token refresh!

2. CLI Options

npx @thuyphuocthinh/mcp-auth-proxy <remote-url> [options]

🧪 Testing

npm run build
npm test

49 unit tests covering all core modules with 100% pass rate.

📄 License

MIT © Thuy Phuoc Thinh