MCP Servers: Connecting AI to Real-Time Data

# Create project directory
mkdir mcp-server-weather
cd mcp-server-weather

# Initialize uv project
uv init

# Create and activate virtual environment
uv venv
source .venv/bin/activate

# Install dependencies
uv add "mcp[cli]" httpx

from typing import Any
import httpx
from mcp.server.fastmcp import FastMCP

# Initialize FastMCP server
mcp = FastMCP("weather")

# Constants
OPENMETEO_API_BASE = "https://api.open-meteo.com/v1"
USER_AGENT = "weather-app/1.0"

# Helper function for API requests
async def make_openmeteo_request(url: str) -> dict[str, Any] | None:
    """Make a request to the Open-Meteo API with proper error handling."""
    headers = {
        "User-Agent": USER_AGENT,
        "Accept": "application/json"
    }
    async with httpx.AsyncClient() as client:
        try:
            response = await client.get(url, headers=headers, timeout=30.0)
            response.raise_for_status()
            return response.json()
        except Exception:
            return None

if __name__ == "__main__":
    mcp.run(transport='stdio')

@mcp.tool()
async def get_current_weather(latitude: float, longitude: float) -> str:
    """Get current weather for a location.

    Args:
        latitude: Latitude of the location
        longitude: Longitude of the location
    """
    
    url = f"{OPENMETEO_API_BASE}/forecast?latitude={latitude}&longitude={longitude}&current=temperature_2m,is_day,showers,cloud_cover,wind_speed_10m,wind_direction_10m,pressure_msl,snowfall,precipitation,relative_humidity_2m,apparent_temperature,rain,weather_code,surface_pressure,wind_gusts_10m"
    
    data = await make_openmeteo_request(url)

    if not data:
        return "Unable to fetch current weather data for this location."

    return data

@mcp.tool()
async def get_forecast(latitude: float, longitude: float, days: int = 7) -> str:
    """Get weather forecast for a location.

    Args:
        latitude: Latitude of the location
        longitude: Longitude of the location  
        days: Number of days to forecast (1-16)
    """
    
    url = f"{OPENMETEO_API_BASE}/forecast?latitude={latitude}&longitude={longitude}&daily=temperature_2m_max,temperature_2m_min,precipitation_sum,wind_speed_10m_max,weather_code&forecast_days={days}"
    
    data = await make_openmeteo_request(url)
    
    if not data:
        return "Unable to fetch forecast data for this location."
    
    return data

# Start MCP server in development mode
mcp dev server.py

# Open browser to http://localhost:5173
# Connect to the server
# Navigate to Tools tab
# Test get_current_weather with coordinates
# Example: latitude=63.4463991, longitude=10.8127596

@mcp.tool()
async def get_location(city: str, country: str = "") -> str:
    """Get coordinates for a city using geocoding.
    
    Args:
        city: Name of the city
        country: Optional country name for disambiguation
    """
    
    query = f"{city},{country}" if country else city
    url = f"https://geocoding-api.open-meteo.com/v1/search?name={query}&count=1&language=en&format=json"
    
    data = await make_openmeteo_request(url)
    
    if not data or not data.get('results'):
        return "Location not found."
    
    return data['results'][0]

{
  "mcpServers": {
    "weather": {
      "command": "uv",
      "args": ["run", "python", "server.py"],
      "cwd": "/path/to/your/mcp-server-weather"
    }
  }
}