JMA Data MCP

Instructions

Implementation Reference

• jma_data_mcp/server.py:183-205 (handler)

  The get_forecast tool handler function, registered via @mcp.tool(). It validates the prefecture against AREA_CODES, fetches the forecast data using fetch_forecast, and returns formatted results or an error.

  @mcp.tool()
  async def get_forecast(prefecture: str) -> dict:
      """Get weather forecast for a prefecture.
  
      Args:
          prefecture: Prefecture name in English (e.g., 'tokyo', 'osaka', 'hokkaido_sapporo')
  
      Returns:
          Weather forecast data
      """
      area_code = AREA_CODES.get(prefecture)
      if not area_code:
          return {
              "error": f"Unknown prefecture: {prefecture}",
              "available": list(AREA_CODES.keys()),
          }
  
      forecast_data = await fetch_forecast(area_code)
      return {
          "prefecture": prefecture,
          "area_code": area_code,
          "forecast": forecast_data,
      }