Simple-MCP-Server-with-Python

The Model Context Protocol (MCP) standardizes the interface between applications and LLMs, allowing for the separation of concerns in providing context, executing code, and managing user interactions. The MCP Python SDK implements the full MCP specification, enabling developers to expose resources, define tools, and create prompts for LLM applications. This tutorial guides you through building a simple MCP server in Python, which exposes data, functionality, and interaction templates to LLMs in a secure and modular fashion. The server can advertise its capabilities, allowing clients to adapt dynamically. The tutorial covers setting up the environment, creating the server, and testing it using the MCP Inspector.

Features

• Expose Resources: Deliver data to LLMs similar to GET endpoints.
• Define Tools: Provide functionality that performs actions or computations like POST endpoints.
• Create Prompts: Offer reusable, templated interactions.
• Dynamic Capability Advertisement: Clients can adapt based on server's advertised features.
• MCP Inspector: A web-based UI for testing and interacting with MCP servers.

MCP Tools

• {'add': 'A tool that adds two numbers together.'}

MCP Resources

• {'greeting': 'A resource that returns a personalized greeting.'}

Usage with Different Platforms

Ubuntu 22.04

bash
sudo add-apt-repository ppa:deadsnakes/ppa -y
sudo apt update
sudo apt install -y python3.11 python3.11-venv python3.11-distutils python3-apt
sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.10 1
sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.11 2
sudo update-alternatives --config python3
curl -sS https://bootstrap.pypa.io/get-pip.py | sudo python3.11
curl -fsSL https://deb.nodesource.com/setup_18.x | sudo -E bash -
sudo apt-get update
sudo apt-get install -y nodejs
python3 -m venv .venv
source .venv/bin/activate
pip install --upgrade pip
pip install -r requirements.txt

Python Script

python
# client.py
import asyncio
from mcp import ClientSession, StdioServerParameters
from mcp.client.stdio import stdio_client

async def main():
    server_params = StdioServerParameters(
        command="python",
        args=["server.py"],
    )

    async with stdio_client(server_params) as (reader, writer):
        async with ClientSession(reader, writer) as session:
            await session.initialize()

            result = await session.call_tool("add", arguments={"a": 3, "b": 4})
            print(f"Result of add tool: {result}")

if __name__ == "__main__":
    asyncio.run(main())