Weather Server

Instructions

Args:
    latitude: Latitude of the location (-90 to 90)
    longitude: Longitude of the location (-180 to 180)

Implementation Reference

• weather.py:230-290 (handler)

  The handler function for the 'get_current_conditions' tool. It validates coordinates, fetches weather points from NWS API, retrieves the nearest observation station, gets latest observations, and formats current conditions including temperature, humidity, wind, etc.

  @mcp.tool()
  async def get_current_conditions(latitude: float, longitude: float) -> str:
      """Get current weather conditions for a location.
  
      Args:
          latitude: Latitude of the location (-90 to 90)
          longitude: Longitude of the location (-180 to 180)
      """
      if not validate_coordinates(latitude, longitude):
          return "Error: Invalid coordinates. Latitude must be between -90 and 90, longitude between -180 and 180."
  
      points_url = f"{NWS_API_BASE}/points/{latitude},{longitude}"
      points_data = await make_nws_request(points_url)
  
      if not points_data or "properties" not in points_data:
          return f"Unable to fetch weather data for coordinates ({latitude}, {longitude})."
  
      observation_url = points_data["properties"].get("observationStations")
      if not observation_url:
          return "No observation stations available for this location."
  
      # Get the nearest observation station
      stations_data = await make_nws_request(observation_url)
      if not stations_data or not stations_data.get("features"):
          return "No observation stations found for this location."
  
      station_id = stations_data["features"][0]["properties"]["stationIdentifier"]
      observations_url = f"{NWS_API_BASE}/stations/{station_id}/observations/latest"
      observations_data = await make_nws_request(observations_url)
  
      if not observations_data or "properties" not in observations_data:
          return "Unable to fetch current observations."
  
      props = observations_data["properties"]
      location_info = points_data["properties"].get("relativeLocation", {})
      location_str = f"{location_info.get('properties', {}).get('city', 'Unknown')}, {location_info.get('properties', {}).get('state', 'Unknown')}"
  
      temp = props.get("temperature", {}).get("value")
      temp_unit = "°C"
      if temp is not None:
          temp_f = (temp * 9/5) + 32
          temp_unit = f"°F ({temp:.1f}°C)"
  
      dewpoint = props.get("dewpoint", {}).get("value")
      humidity = props.get("relativeHumidity", {}).get("value")
      wind_speed = props.get("windSpeed", {}).get("value")
      wind_direction = props.get("windDirection", {}).get("value")
      pressure = props.get("barometricPressure", {}).get("value")
      visibility = props.get("visibility", {}).get("value")
      text_description = props.get("textDescription", "N/A")
  
      result = f"Current Conditions for {location_str}:\n\n"
      result += f"Temperature: {temp_f:.1f}{temp_unit}\n" if temp is not None else "Temperature: N/A\n"
      result += f"Conditions: {text_description}\n"
      result += f"Humidity: {humidity:.1f}%\n" if humidity is not None else ""
      result += f"Dewpoint: {dewpoint * 9/5 + 32:.1f}°F\n" if dewpoint is not None else ""
      result += f"Wind: {wind_speed * 2.237:.1f} mph from {wind_direction}°\n" if wind_speed is not None and wind_direction is not None else ""
      result += f"Pressure: {pressure / 100:.2f} hPa\n" if pressure is not None else ""
      result += f"Visibility: {visibility / 1609.34:.2f} miles\n" if visibility is not None else ""
  
      return result

• weather.py:230-230 (registration)

  The @mcp.tool() decorator registers the get_current_conditions function as an MCP tool.

  @mcp.tool()

• weather.py:28-31 (helper)

  Helper function to validate input coordinates used by get_current_conditions.

  def validate_coordinates(latitude: float, longitude: float) -> bool:
      """Validate that coordinates are within valid ranges."""
      return -90 <= latitude <= 90 and -180 <= longitude <= 180

• weather.py:73-92 (helper)

  Helper function to make HTTP requests to NWS API endpoints, used multiple times in get_current_conditions.

  async def make_nws_request(url: str) -> dict[str, Any] | None:
      """Make a request to the NWS API with proper error handling."""
      headers = {
          "User-Agent": USER_AGENT,
          "Accept": "application/geo+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 httpx.HTTPStatusError as e:
              if e.response.status_code == 404:
                  return None
              return None
          except (httpx.RequestError, httpx.TimeoutException):
              return None
          except Exception:
              return None

• weather.py:232-237 (schema)

  Docstring providing input schema description for the tool parameters.

  """Get current weather conditions for a location.
  
  Args:
      latitude: Latitude of the location (-90 to 90)
      longitude: Longitude of the location (-180 to 180)
  """