MCP-Demo

🧠 Model Context Protocol (MCP) Example – Python Implementation

This repository provides a minimal yet functional example of the Model Context Protocol (MCP) using Python. It demonstrates how a Large Language Model (LLM) agent can communicate with enterprise systems through a standardized client-server interface using JSON-RPC over HTTP, including support for Server-Sent Events (SSE).

You can read my blog to understand the subject better: https://srivatssan.medium.com/model-context-protocol-exhaustively-explained-f5a30a87a3ff?sk=1b971265640303c66b04377371c82102

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📦 Repository Structure

mcp-protocol-example/
├── client/
│   └── main.py       # Python MCP client using JSON-RPC
├── server/
│   └── main.py       # FastAPI-based MCP server with /rpc and /events endpoints

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🚀 How to Run This Example

1️⃣ Start the Server

Make sure you have FastAPI and Uvicorn installed:

pip install fastapi uvicorn

Then, start the MCP server:

cd server
uvicorn main:app --reload

This starts a FastAPI server with:

• POST /rpc: JSON-RPC handler for tool listing and invocation
• GET /events: Simulated SSE endpoint emitting heartbeat messages every 5 seconds

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2️⃣ Run the Client

Install the required Python requests package:

pip install requests

Then run the client to interact with the server:

cd client
python main.py

Output:

Tools: [{'name': 'greet', 'description': 'Greets the user', ...}]
Response: {'message': 'Hello, Sri!'}

You can run http://localhost:8000/events and you should see the heartbeat event being returned like the one shown below.

_data: {'event': 'heartbeat'}

data: {'event': 'heartbeat'} _ ...

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⚙️ What It Demonstrates

• A basic MCP server exposing tools via tools/list and tools/call
• A client sending JSON-RPC requests to list and call tools
• Simulated real-time connection using /events SSE endpoint
• Modular structure ready to extend for resources/ and prompts/ support

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🧩 Next Steps

You can expand this prototype by:

• Adding more tools with different schemas
• Supporting resources/list and resources/read
• Managing prompt templates with prompts/get
• Implementing authentication and access control
• Handling streaming responses from server to client

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📚 References

• Model Context Protocol (official site)
• JSON-RPC 2.0 Specification
• FastAPI Documentation
• Server-Sent Events (MDN)

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Created with ❤️ by Srivatssan Srinivasan