Slim MCP

Instructions

Implementation Reference

• src/claude_tools/weather.py:44-69 (handler)

  The core handler function implementing the get_forecast tool. It queries the National Weather Service API using provided latitude and longitude to retrieve and format the weather forecast for the next 5 periods.

  async def get_forecast(latitude: float, longitude: float) -> str:
      """Get weather forecast for a location."""
      # First get the forecast grid endpoint
      points_url = f"{NWS_API_BASE}/points/{latitude},{longitude}"
      points_data = await make_nws_request(points_url)
      if not points_data:
          return "Unable to fetch forecast data for this location."
      
      # Get the forecast URL from the points response
      forecast_url = points_data["properties"]["forecast"]
      forecast_data = await make_nws_request(forecast_url)
      if not forecast_data:
          return "Unable to fetch detailed forecast."
      
      # Format the periods into a readable forecast
      periods = forecast_data["properties"]["periods"]
      forecasts = []
      for period in periods[:5]:  # Only show next 5 periods
          forecast = f"""
  {period['name']}:
  Temperature: {period['temperature']}°{period['temperatureUnit']}
  Wind: {period['windSpeed']} {period['windDirection']}
  Forecast: {period['detailedForecast']}
  """
          forecasts.append(forecast)
      return "\n---\n".join(forecasts)

• src/claude_tools/weather.py:71-75 (registration)

  The registration function that uses mcp.tool() decorator to register the get_forecast tool (along with get_alerts) with the MCP server.

  def register_weather_tools(mcp):
      """Register all weather tools with the MCP server."""
      mcp.tool()(get_alerts)
      mcp.tool()(get_forecast)

• src/claude_tools/weather.py:8-20 (helper)

  Key helper utility function used by get_forecast to make HTTP requests to the NWS API endpoints.

  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 Exception:
              return None