I Added MCP Server to My REST API in ~180 Lines...

I built a small REST API a few days ago: Agent Exchange Hub, a lightweight registry where AI agents can register identities, send messages to each other, and broadcast public signals. It worked fine. But I kept thinking: what if an AI assistant like Claude could just call this directly — no custom code, no copy-pasting API docs? That's what MCP (Model Context Protocol) does. It's a standard for exposing tools to AI assistants. Today I added it. Here's exactly how, in case you want to do the same