shareai-lab/learn-claude-code/mcp-builder

# Create project
mkdir my-mcp-server && cd my-mcp-server
python3 -m venv venv && source venv/bin/activate
 
# Install MCP SDK
pip install mcp

#!/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())

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

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

// src/index.ts
import { Server } from "@modelcontextprotocol/sdk/server/index.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
const server = new Server({
  name: "my-server",
  version: "1.0.0",
});
// Define tools
server.setRequestHandler("tools/list", async () => ({
  tools: [
    {
      name: "hello",
      description: "Say hello to someone",
      inputSchema: {
        type: "object",
        properties: {
          name: { type: "string", description: "Name to greet" },
        },
        required: ["name"],
      },
    },
  ],
}));
server.setRequestHandler("tools/call", async (request) => {
  if (request.params.name === "hello") {
    const name = request.params.arguments.name;
    return { content: [{ type: "text", text: `Hello, ${name}!` }] };
  }
  throw new Error("Unknown tool");
});
// Start server
const transport = new StdioServerTransport();
server.connect(transport);

import httpx
from mcp.server import Server
server = Server("weather-server")
@server.tool()
async def get_weather(city: str) -> str:
    """Get current weather for a city."""
    async with httpx.AsyncClient() as client:
        resp = await client.get(
            f"https://api.weatherapi.com/v1/current.json",
            params={"key": "YOUR_API_KEY", "q": city}
        )
        data = resp.json()
        return f"{city}: {data['current']['temp_c']}C, {data['current']['condition']['text']}"

import sqlite3
from mcp.server import Server
server = Server("db-server")
@server.tool()
async def query_db(sql: str) -> str:
    """Execute a read-only SQL query."""
    if not sql.strip().upper().startswith("SELECT"):
        return "Error: Only SELECT queries allowed"
    conn = sqlite3.connect("data.db")
    cursor = conn.execute(sql)
    rows = cursor.fetchall()
    conn.close()
    return str(rows)

@server.resource("config://settings")
async def get_settings() -> str:
    """Application settings."""
    return open("settings.json").read()
@server.resource("file://{path}")
async def read_file(path: str) -> str:
    """Read a file from the workspace."""
    return open(path).read()

# Test with MCP Inspector
npx @anthropics/mcp-inspector python3 my_server.py
 
# Or send test messages directly
echo '{"jsonrpc":"2.0","id":1,"method":"tools/list"}' | python3 my_server.py