Minimal MCP Server (Python SDK)

# server.py
from mcp.server.fastmcp import FastMCP

app = FastMCP("hello-server")

@app.tool()
async def get_stock_price(symbol: str) -> str:
    """Get the current stock price for a ticker symbol (toy implementation)."""
    prices = {"AAPL": 198.50, "GOOGL": 178.25, "MSFT": 425.00}
    p = prices.get(symbol.upper())
    if p is None:
        return f"Unknown symbol: {symbol}"
    return f"{symbol.upper()}: ${p:.2f}"

@app.resource("greeting://hello")
def hello() -> str:
    return "Hello from a tiny MCP server."

if __name__ == "__main__":
    app.run()  # speaks stdio by default

$ python server.py
# Server is now listening on stdio. To exercise it from a client:
$ uvx mcp-cli connect "python server.py" tools/list