MCP Weather Sample

Instructions

獲取美國特定州份的警報資料.

Args:
    state (str): 美國州份的縮寫 (e.g., "CA", "TX", "NY")
    
Returns:
    str: 警報資料的文字描述

Implementation Reference

• src/servers/weather/stdio/weather.py:43-64 (handler)

  get_alerts handler for stdio transport - fetches weather alerts from NOAA API for a given US state code. Uses @mcp.tool() decorator for registration.

  @mcp.tool()
  async def get_alerts(state: str) -> str:
      """
      獲取美國特定州份的警報資料.
  
      Args:
          state (str): 美國州份的縮寫 (e.g., "CA", "TX", "NY")
          
      Returns:
          str: 警報資料的文字描述
      """
      url = f"{NWS_API_BASE_URL}/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 found for the given state."
      
      alerts = [format_alert(feature) for feature in data["features"]]
      return "\n\n".join(alerts)

• src/servers/weather/streamable-http/mcp-weather.py:106-126 (handler)

  get_alerts handler for streamable-http transport - similar logic with added Context parameter for logging via ctx.info(). Uses @mcp.tool() decorator.

  @mcp.tool()
  async def get_alerts(state: str, ctx: Context) -> str:
      """Get weather alerts for a US state.
  
      Args:
          state: Two-letter US state code (e.g. CA, NY)
      """
      await ctx.info(f"Fetching alerts for state: {state}")
      url = f"{NWS_API_BASE}/alerts/active/area/{state}"
      data = await make_nws_request(url)
  
      await ctx.info(f"Received data: {data}")
  
      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)

• src/servers/weather/sse/mcp-weather.py:106-126 (handler)

  get_alerts handler for SSE transport - identical to streamable-http version with Context parameter for logging. Uses @mcp.tool() decorator.

  @mcp.tool()
  async def get_alerts(state: str, ctx: Context) -> str:
      """Get weather alerts for a US state.
  
      Args:
          state: Two-letter US state code (e.g. CA, NY)
      """
      await ctx.info(f"Fetching alerts for state: {state}")
      url = f"{NWS_API_BASE}/alerts/active/area/{state}"
      data = await make_nws_request(url)
  
      await ctx.info(f"Received data: {data}")
  
      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)

• src/servers/weather/stdio/weather.py:12-28 (helper)

  Helper function make_nws_request - handles HTTP requests to NOAA API with proper headers and error handling.

  async def make_nws_request(url: str) -> dict[str, Any] | None:
      """
      發送 HTTP 請求到 NOAA 天氣 API 並返回 JSON 響應
      """
      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:
              print(f"HTTP error occurred: {e}")
              return None

• src/servers/weather/stdio/weather.py:30-41 (helper)

  Helper function format_alert - formats individual alert feature into readable string with event, area, severity, description, and instructions.

  def format_alert(feature: dict) -> str:
      """
      格式化 NOAA 警報資料
      """
      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")}
  """