mcp-web-url-reader

An MCP server that exposes a single tool, read_web_url, which fetches absolute URLs with curl -sL after prepending a configurable CUSTOM_PREFIX on the server side. This server uses the MCP TypeScript/JavaScript SDK and serves a Streamable HTTP endpoint at /mcp for compatibility across many AI applications.

Features

• Streamable HTTP transport with session management on /mcp (POST for JSON-RPC requests, GET for SSE notifications, DELETE to end sessions).

• CORS enabled with Mcp-Session-Id exposed for browser-based clients, as recommended.

• Tool: read_web_url with input { url: string }, which runs curl -sL CUSTOM_PREFIX/<url> and returns the response text.

• Tiny Docker image based on node:20-alpine with curl installed via apk add --no-cache curl.

Environment Variables

• INTERNAL_PORT (default: 8080): Port the HTTP server listens on inside the container. [web:1]

• CUSTOM_PREFIX (required for prefixing): The string to prepend before the requested absolute URL, e.g., https://your-proxy/forward.

Run

• Open http://localhost:8080/ for a basic health probe and connect your MCP client to http://localhost:8080/mcp.

• The MCP endpoint is on http://localhost:8080/mcp with Streamable HTTP semantics for POST/GET/DELETE and CORS exposure for Mcp-Session-Id.

Docker Compose

See docker-compose.yml for a working example service mapping 8080:8080 and injecting both environment variables.

MCP Client Integration

The server exposes tools over Streamable HTTP: initialize a session with a POST to /mcp, reuse Mcp-Session-Id from the response, then call tools/call with { name: "read_web_url", arguments: { url: "https://example.com" } }. The server will run curl -sL CUSTOM_PREFIX/https://example.com and return text content. Ensure the Mcp-Session-Id header is included in subsequent requests and allowed via CORS.