OpenWeatherMap MCP Server

Instructions

Implementation Reference

• src/main.ts:385-446 (handler)

  The execute handler function implementing the core logic for the get-minutely-forecast tool: resolves location, fetches minutely precipitation forecast from OpenWeatherMap API, formats the response as JSON with precipitation amounts and descriptions.

  execute: async (args, { session, log }) => {
    try {
      log.info("Getting minutely weather forecast", { 
        location: args.location,
        limit: args.limit
      });
      
      // Get OpenWeather client
      const client = getOpenWeatherClient(session as SessionData | undefined);
      
      // Configure client for this request
      configureClientForLocation(client, args.location);
      
      // Fetch minutely forecast data
      const requestedMinutes = args.limit || 60;
      const minutelyData = await client.getMinutelyForecast(requestedMinutes);
      
      log.info("Successfully retrieved minutely weather forecast", { 
        location: args.location,
        minutes: minutelyData.length
      });
      
      // Format the response
      const formattedForecast = JSON.stringify({
        location: args.location,
        minutes_requested: requestedMinutes,
        forecast: minutelyData.map((minute, index) => ({
          minute_offset: index + 1,
          time: minute.dt.toISOString(),
          precipitation: minute.weather.rain,
          precipitation_description: minute.weather.rain > 0 ? 
            (minute.weather.rain < 0.1 ? 'Light rain' : 
             minute.weather.rain < 0.5 ? 'Moderate rain' : 'Heavy rain') : 'No precipitation'
        }))
      }, null, 2);
      
      return {
        content: [
          {
            type: "text",
            text: formattedForecast
          }
        ]
      };
    } catch (error) {
      log.error("Failed to get minutely weather forecast", { 
        error: error instanceof Error ? error.message : 'Unknown error' 
      });
      
      // Provide helpful error messages
      if (error instanceof Error) {
        if (error.message.includes('city not found')) {
          throw new Error(`Location "${args.location}" not found. Please check the spelling or try using coordinates.`);
        }
        if (error.message.includes('Invalid API key')) {
          throw new Error('Invalid OpenWeatherMap API key. Please check your configuration.');
        }
      }
      
      throw new Error(`Failed to get minutely weather forecast: ${error instanceof Error ? error.message : 'Unknown error'}`);
    }
  }

• src/main.ts:381-447 (registration)

  Registration of the get-minutely-forecast tool using server.addTool, including name, description, input schema, and execute handler.

  server.addTool({
    name: "get-minutely-forecast",
    description: "Get minute-by-minute precipitation forecast for next hour",
    parameters: getMinutelyForecastSchema,
    execute: async (args, { session, log }) => {
      try {
        log.info("Getting minutely weather forecast", { 
          location: args.location,
          limit: args.limit
        });
        
        // Get OpenWeather client
        const client = getOpenWeatherClient(session as SessionData | undefined);
        
        // Configure client for this request
        configureClientForLocation(client, args.location);
        
        // Fetch minutely forecast data
        const requestedMinutes = args.limit || 60;
        const minutelyData = await client.getMinutelyForecast(requestedMinutes);
        
        log.info("Successfully retrieved minutely weather forecast", { 
          location: args.location,
          minutes: minutelyData.length
        });
        
        // Format the response
        const formattedForecast = JSON.stringify({
          location: args.location,
          minutes_requested: requestedMinutes,
          forecast: minutelyData.map((minute, index) => ({
            minute_offset: index + 1,
            time: minute.dt.toISOString(),
            precipitation: minute.weather.rain,
            precipitation_description: minute.weather.rain > 0 ? 
              (minute.weather.rain < 0.1 ? 'Light rain' : 
               minute.weather.rain < 0.5 ? 'Moderate rain' : 'Heavy rain') : 'No precipitation'
          }))
        }, null, 2);
        
        return {
          content: [
            {
              type: "text",
              text: formattedForecast
            }
          ]
        };
      } catch (error) {
        log.error("Failed to get minutely weather forecast", { 
          error: error instanceof Error ? error.message : 'Unknown error' 
        });
        
        // Provide helpful error messages
        if (error instanceof Error) {
          if (error.message.includes('city not found')) {
            throw new Error(`Location "${args.location}" not found. Please check the spelling or try using coordinates.`);
          }
          if (error.message.includes('Invalid API key')) {
            throw new Error('Invalid OpenWeatherMap API key. Please check your configuration.');
          }
        }
        
        throw new Error(`Failed to get minutely weather forecast: ${error instanceof Error ? error.message : 'Unknown error'}`);
      }
    }
  });

• src/schemas.ts:44-47 (schema)

  Zod schema defining the input parameters for the get-minutely-forecast tool: location (string) and optional limit (number 1-60).

  export const getMinutelyForecastSchema = z.object({
    location: z.string().describe("City name (e.g., 'New York') or coordinates (e.g., 'lat,lon')"),
    limit: z.number().min(1).max(60).optional().describe("Number of minutes to forecast (1-60, default: 60)"),
  });