Weather MCP Server

Instructions

Implementation Reference

• server.py:177-184 (handler)

  Handler logic for the 'weather_current' tool: parses arguments, validates location query, fetches current weather data using the shared 'fetch' helper, and formats the JSON response.

  if tool_name == "weather_current":
      q = arguments.get("q")
      aqi = arguments.get("aqi", "no")
      if not q:
          raise ValueError("Location (q) is required")
      result = await fetch("current.json", {"q": q, "aqi": aqi})
      content = json.dumps(result, indent=2)

• server.py:112-126 (schema)

  Input schema defining the parameters for the 'weather_current' tool: required 'q' for location and optional 'aqi'.

  "inputSchema": {
      "type": "object",
      "properties": {
          "q": {
              "type": "string",
              "description": "Location query (city name, lat/lon, postal code, etc)"
          },
          "aqi": {
              "type": "string",
              "description": "Include air quality data ('yes' or 'no')",
              "default": "no"
          }
      },
      "required": ["q"]
  }

• server.py:109-127 (registration)

  Registration of the 'weather_current' tool in the tools/list response, including name, description, and schema.

  {
      "name": "weather_current",
      "description": "Get current weather for a location",
      "inputSchema": {
          "type": "object",
          "properties": {
              "q": {
                  "type": "string",
                  "description": "Location query (city name, lat/lon, postal code, etc)"
              },
              "aqi": {
                  "type": "string",
                  "description": "Include air quality data ('yes' or 'no')",
                  "default": "no"
              }
          },
          "required": ["q"]
      }
  },

• server.py:42-79 (helper)

  Shared 'fetch' utility function that performs HTTP requests to the WeatherAPI for all tools, including 'weather_current', handling API key, errors, and JSON parsing.

  async def fetch(endpoint: str, params: dict) -> dict:
      """Perform async GET to WeatherAPI and return JSON."""
      logger.debug(f"fetch() called with endpoint: {endpoint}, params: {params}")
      
      if not WEATHER_API_KEY:
          logger.error("Weather API key not set.")
          raise Exception("Weather API key not set.")
  
      params["key"] = WEATHER_API_KEY
      url = f"https://api.weatherapi.com/v1/{endpoint}"
      logger.info(f"Requesting {url}")
      
      async with httpx.AsyncClient() as client:
          logger.debug("HTTPx client created")
          try:
              resp = await client.get(url, params=params)
              logger.debug(f"HTTP response received: status={resp.status_code}")
              
              if resp.status_code != 200:
                  try:
                      error_data = resp.json()
                      detail = error_data.get("error", {}).get("message", resp.text)
                  except:
                      detail = resp.text
                  logger.error(f"WeatherAPI error {resp.status_code}: {detail}")
                  raise Exception(f"WeatherAPI error {resp.status_code}: {detail}")
                  
              data = resp.json()
              logger.debug(f"JSON parsing successful")
              logger.info(f"WeatherAPI success: {url}")
              return data
              
          except httpx.RequestError as e:
              logger.error(f"HTTPX request error: {e}")
              raise Exception(f"Request error: {e}")
          except Exception as e:
              logger.error(f"Unexpected error: {e}")
              raise Exception(f"Unexpected error: {e}")