mcp-sse

This MCP Server implements a Bearer Token authenticated MCP over Server-Sent Events (SSE). It exposes a set of example tools that demonstrate the four basic arithmetic operations, registered as MCP tools and usable by clients over the /sse and /messages endpoints. Clients connect via SSE to establish a session, receive the list of available tools, and then send messages to invoke those tools. Authentication is performed by including an Authorization header with a Bearer token for the initial connection. The server is designed to be developer-friendly, using ts-node for development and a compiled dist/index.js for production deployments.

Prerequisites:

• Node.js 20 or newer
• npm
• TypeScript (for development)

Install and run in development:

git clone <REPO_URL>
cd mcp-sse
npm install

# Run in development (uses ts-node via npm scripts)
npm run dev

Run in production (after building):

npm run build
node dist/index.js

Configuration:

• Create a .env file at the project root and define your Bearer token and port:

BEARER_TOKEN=your-token-goes-here
PORT=3001

Notes:

• Ensure the PORT in your environment matches any reverse proxy or firewall rules.
• The server reads BEARER_TOKEN from environment variables for authentication.

Tips:

• If you encounter authentication issues, confirm that the Authorization header follows the format: Authorization: Bearer <token>.
• For local development, you can use the inspector tool via npm run dev:inspect to view tools in a web interface at http://127.0.0.1:6274.
• The server uses SSE for real-time communication; ensure your client supports EventSource and maintains the connection for ongoing messages.
• Common issue: forgetting to set BEARER_TOKEN in .env or mismatch between the token used by the client and the one configured on the server.