MCP Server Building Skill

You now have expertise in building MCP (Model Context Protocol) servers. MCP enables Claude to interact with external services through a standardized protocol.

What is MCP?

MCP servers expose:

• Tools: Functions Claude can call (like API endpoints)
• Resources: Data Claude can read (like files or database records)
• Prompts: Pre-built prompt templates

Quick Start: Python MCP Server

1. Project Setup

# Create project
mkdir my-mcp-server && cd my-mcp-server
python3 -m venv venv && source venv/bin/activate

# Install MCP SDK
pip install mcp

2. Basic Server Template

#!/usr/bin/env python3
"""my_server.py - A simple MCP server"""

from mcp.server import Server
from mcp.server.stdio import stdio_server
from mcp.types import Tool, TextContent

# Create server instance
server = Server("my-server")

# Define a tool
@server.tool()
async def hello(name: str) -> str:
    """Say hello to someone.

    Args:
        name: The name to greet
    """
    return f"Hello, {name}!"

@server.tool()
async def add_numbers(a: int, b: int) -> str:
    """Add two numbers together.

    Args:
        a: First number
        b: Second number
    """
    return str(a + b)

# Run server
async def main():
    async with stdio_server() as (read, write):
        await server.run(read, write)

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

3. Register with Claude

Add to ~/.claude/mcp.json:

{
  "mcpServers": {
    "my-server": {
      "command": "python3",
      "args": ["/path/to/my_server.py"]
    }
  }
}

TypeScript MCP Server

1. Setup

mkdir my-mcp-server && cd my-mcp-server
npm init -y
npm install @modelcontextprotocol/sdk

2. Template

// src/index.ts
import { Server } from "@modelcontextprotocol/sdk/server/index.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";