Weather MCP Server

Instructions

Implementation Reference

• weather.py:38-55 (handler)

  The main handler function for the 'get_alerts' tool. It fetches active weather alerts from the National Weather Service API for a given US state code, processes the data, and formats the results into a readable string.
  @mcp.tool() async def get_alerts(state: str) -> str: """Get weather alerts for a US state. Args: state: Two-letter US state code (e.g. CA, NY) """ url = f"{NWS_API_BASE}/alerts/active/area/{state}" data = await make_nws_request(url) if not data or "features" not in data: return "Unable to fetch alerts or no alerts found." if not data["features"]: return "No active alerts for this state." alerts = [format_alert(feature) for feature in data["features"]] return "\n---\n".join(alerts)
• weather.py:12-24 (helper)

  Helper function to make HTTP requests to the NWS API with proper headers, timeout, and error handling.
  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
• weather.py:26-35 (helper)

  Helper function to format a single weather alert feature into a human-readable string.
  def format_alert(feature: dict) -> str: """Format an alert feature into a readable string.""" props = feature["properties"] return f""" Event: {props.get('event', 'Unknown')} Area: {props.get('areaDesc', 'Unknown')} Severity: {props.get('severity', 'Unknown')} Description: {props.get('description', 'No description available')} Instructions: {props.get('instruction', 'No specific instructions provided')} """
• weather.py:38-38 (registration)

  The @mcp.tool() decorator registers the get_alerts function as an MCP tool.
  @mcp.tool()
• weather.py:40-44 (schema)

  The docstring provides the input schema description for the tool, specifying the 'state' parameter.
  """Get weather alerts for a US state. Args: state: Two-letter US state code (e.g. CA, NY) """