What MCP is
One connection, every AI app
In the LangGraph course, Café Helper's tools were Python functions inside the agent's program. That works — but only for that one program. If the café also wanted its booking tool in a chat app, a coding assistant and a phone app, each would need its own copy. With 10 AI apps and 10 systems, that's 100 connections to build and keep working.
The Model Context Protocol (MCP), released as an open standard by Anthropic in late 2024 and now supported across the industry, turns that into 10 + 10. Each system gets one MCP server. Each AI app gets one MCP client. Any client can use any server — like USB-C for AI.
The three roles
| Role | What it is | Example |
|---|---|---|
| Host | The AI app a person uses | Claude Desktop, VS Code, your LangGraph agent |
| Client | The part of the host that talks to one server | One connection per server |
| Server | A program that offers capabilities to AI apps | Corner Café's server, a GitHub server, a files server |
What a server can offer
| What | Who decides to use it | Café examples | |
|---|---|---|---|
| Tools | Functions the AI can call | The model | Check free tables, request a booking, search the handbook |
| Resources | Information the app can read | The app (or the person) | The menu, opening hours, one day's bookings |
| Prompts | Ready-made instructions with blanks to fill | The person | "Reply to a customer", "Welcome a new staff member" |
Under the hood, client and server exchange JSON-RPC messages — small JSON requests and replies like "list your tools" and "call booking_times with these arguments". You'll see them in the Inspector. The SDK handles all of it, so you just write Python functions.
What you'll build
- A first server, tested in the MCP Inspector
- Corner Café's tools — and your own Python client
- Resources, prompts, and the handbook search from the RAG course
- A LangGraph agent that uses several MCP servers, and desktop AI apps
- The server over HTTP, with a token, security and tests
- Sharing servers, and the MCP ecosystem
Try it
- Which systems at a workplace you know would be useful to connect to AI? Which should never be connected?
- Download the course files from this lesson.
Downloads
1 file to download once you enrol.