Model Context Protocol
What is MCP?
An open standard for connecting AI apps to the tools and data they use. A server says what it can do, the app shows that to the model, and when the model wants something the app calls the server and hands the result back.
- Host
- the AI app you use: Claude, Cursor, ChatGPT, an agent
- Server
- a small program exposing tools, data or prompts
- Model
- decides what to use; never talks to a server directly
- Not REST
- JSON-RPC over stdin/stdout or one HTTP endpoint, and servers can talk back
- Not just JSON-RPC
- JSON-RPC is the envelope. MCP defines what goes in it: the methods, capability negotiation, transports and auth
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