KNMI Weather MCP

Instructions

Get and interpret weather data for a location in the Netherlands

Args:
    location: City or place name in the Netherlands
Returns:
    A natural language interpretation of the current weather conditions

Implementation Reference

• src/knmi_weather_mcp/server.py:159-190 (handler)

  The core handler function for the 'what_is_the_weather_like_in' MCP tool. It is registered via @mcp.tool() decorator, fetches coordinates and weather data, and generates a natural language summary using a helper prompt.

  @mcp.tool()
  async def what_is_the_weather_like_in(location: str, ctx: Context) -> str:
      """
      Get and interpret weather data for a location in the Netherlands
  
      Args:
          location: City or place name in the Netherlands
      Returns:
          A natural language interpretation of the current weather conditions
      """
      try:
          # Get the coordinates for the location
          coords = await get_coordinates(location)
  
          # Get the weather data
          weather_data = await weather_service.get_weather_by_location(location, ctx)
  
          # Convert to dict and ensure all fields are present
          data_dict = weather_data.dict()
  
          # Add location information
          data_dict["requested_location"] = location
          data_dict["location_coordinates"] = {
              "latitude": coords.latitude,
              "longitude": coords.longitude,
          }
  
          # Use the interpretation prompt to analyze it
          return weather_interpretation(data_dict)
      except Exception as e:
          logger.error(f"Error getting weather for {location}: {str(e)}")
          return f"Error: Unable to get weather data for {location}. {str(e)}"

• src/knmi_weather_mcp/server.py:194-227 (helper)

  Supporting prompt function invoked by the tool handler to format raw weather data into a structured prompt for natural language interpretation.

  @mcp.prompt()
  def weather_interpretation(raw_data: Dict[str, Any]) -> str:
      """Help Claude interpret raw weather data"""
      try:
          location = raw_data.get("requested_location", "Unknown location")
          coords = raw_data.get("location_coordinates", {})
          lat = coords.get("latitude", 0.0)
          lon = coords.get("longitude", 0.0)
          station_name = raw_data.get("station_name", "Unknown station")
          station_id = raw_data.get("station_id", "Unknown ID")
          timestamp = raw_data.get("timestamp", "Unknown time")
  
          return f"""Please analyze this weather data from KNMI and provide:
          1. A clear summary of current conditions
          2. Important weather measurements and their values
          3. Any notable patterns or extreme values
          4. Relevant clothing advice based on the conditions
          
          Location: {location} ({lat:.3f}°N, {lon:.3f}°E)
          Weather station: {station_name} ({station_id}) at {timestamp}
          
          Current measurements:
          - Temperature: {raw_data.get("temperature", "N/A")}°C
          - Humidity: {raw_data.get("humidity", "N/A")}%
          - Wind Speed: {raw_data.get("wind_speed", "N/A")} m/s
          - Wind Direction: {raw_data.get("wind_direction", "N/A")} degrees
          - Precipitation: {raw_data.get("precipitation", "N/A")} mm
          - Visibility: {raw_data.get("visibility", "N/A")} meters
          - Pressure: {raw_data.get("pressure", "N/A")} hPa
          """
      except Exception as e:
          logger.error(f"Error formatting weather interpretation: {str(e)}")
          return "Error: Unable to interpret weather data due to missing or invalid data."