OpenWeatherMap MCP Server

Instructions

Input Schema

Input Schema (JSON Schema)

Implementation Reference

• src/main.ts:700-867 (handler)

  The complete handler and registration for the 'get-onecall-weather' tool. It uses coordinates to fetch comprehensive OneCall weather data (current, minutely, hourly, daily forecasts, and alerts) via the OpenWeather client, formats it into a structured JSON response.
  server.addTool({ name: "get-onecall-weather", description: "Get comprehensive weather data (current + 7-day forecast)", parameters: getOneCallWeatherSchema, execute: async (args, { session, log }) => { try { log.info("Getting OneCall weather data", { latitude: args.latitude, longitude: args.longitude }); // Get OpenWeather client const client = getOpenWeatherClient(session as SessionData | undefined); // Set coordinates for OneCall API client.setLocationByCoordinates(args.latitude, args.longitude); // Set units if provided if (args.units) { client.setUnits(args.units); } // Fetch comprehensive weather data const weatherData = await client.getEverything(); log.info("Successfully retrieved OneCall weather data", { latitude: args.latitude, longitude: args.longitude, has_current: !!weatherData.current, daily_count: weatherData.daily?.length || 0, hourly_count: weatherData.hourly?.length || 0 }); // Format the comprehensive response const formattedData = { location: { latitude: args.latitude, longitude: args.longitude, timezone: weatherData.timezone, timezone_offset: weatherData.timezoneOffset }, current: weatherData.current ? { datetime: weatherData.current.dt.toISOString(), temperature: weatherData.current.weather.temp.cur, feels_like: weatherData.current.weather.feelsLike.cur, pressure: weatherData.current.weather.pressure, humidity: weatherData.current.weather.humidity, dew_point: weatherData.current.weather.dewPoint, uv_index: weatherData.current.weather.uvi, clouds: weatherData.current.weather.clouds, visibility: weatherData.current.weather.visibility, wind: { speed: weatherData.current.weather.wind.speed, direction: weatherData.current.weather.wind.deg, gust: weatherData.current.weather.wind.gust }, weather: { main: weatherData.current.weather.main, description: weatherData.current.weather.description, icon: weatherData.current.weather.icon }, rain: weatherData.current.weather.rain, snow: weatherData.current.weather.snow } : null, minutely: weatherData.minutely?.slice(0, 60).map((minute, index) => ({ minute_offset: index + 1, time: minute.dt.toISOString(), precipitation: minute.weather.rain })) || [], hourly: weatherData.hourly?.slice(0, 48).map(hour => ({ datetime: hour.dt.toISOString(), temperature: hour.weather.temp.cur, feels_like: hour.weather.feelsLike.cur, pressure: hour.weather.pressure, humidity: hour.weather.humidity, dew_point: hour.weather.dewPoint, uv_index: hour.weather.uvi, clouds: hour.weather.clouds, visibility: hour.weather.visibility, wind: { speed: hour.weather.wind.speed, direction: hour.weather.wind.deg, gust: hour.weather.wind.gust }, weather: { main: hour.weather.main, description: hour.weather.description, icon: hour.weather.icon }, precipitation_probability: hour.weather.pop, rain: hour.weather.rain, snow: hour.weather.snow })) || [], daily: weatherData.daily?.slice(0, 7).map(day => ({ date: day.dt.toISOString().split('T')[0], temperature: { min: day.weather.temp.min, max: day.weather.temp.max, morning: day.weather.temp.morn, day: day.weather.temp.day, evening: day.weather.temp.eve, night: day.weather.temp.night }, feels_like: { morning: day.weather.feelsLike.morn, day: day.weather.feelsLike.day, evening: day.weather.feelsLike.eve, night: day.weather.feelsLike.night }, pressure: day.weather.pressure, humidity: day.weather.humidity, dew_point: day.weather.dewPoint, wind: { speed: day.weather.wind.speed, direction: day.weather.wind.deg, gust: day.weather.wind.gust }, weather: { main: day.weather.main, description: day.weather.description, icon: day.weather.icon }, clouds: day.weather.clouds, precipitation_probability: day.weather.pop, rain: day.weather.rain, snow: day.weather.snow, uv_index: day.weather.uvi, moon_phase: day.astronomical.moonPhase, sunrise: day.astronomical.sunrise.toISOString(), sunset: day.astronomical.sunset.toISOString() })) || [], alerts: weatherData.alerts?.map(alert => ({ sender: alert.sender_name, event: alert.event, start_time: new Date(alert.start * 1000).toISOString(), end_time: new Date(alert.end * 1000).toISOString(), description: alert.description, tags: alert.tags })) || [] }; return { content: [ { type: "text", text: JSON.stringify(formattedData, null, 2) } ] }; } catch (error) { log.error("Failed to get OneCall weather", { error: error instanceof Error ? error.message : 'Unknown error' }); // Provide helpful error messages if (error instanceof Error) { if (error.message.includes('Invalid coordinates')) { throw new Error(`Invalid coordinates: latitude must be between -90 and 90, longitude must be between -180 and 180.`); } if (error.message.includes('Invalid API key')) { throw new Error('Invalid OpenWeatherMap API key. Please check your configuration.'); } } throw new Error(`Failed to get OneCall weather: ${error instanceof Error ? error.message : 'Unknown error'}`); } } });
• src/schemas.ts:71-76 (schema)

  Zod schema defining the input parameters for the get-onecall-weather tool: required latitude and longitude, optional units and exclude options.
  export const getOneCallWeatherSchema = z.object({ latitude: z.number().min(-90).max(90).describe("Latitude coordinate"), longitude: z.number().min(-180).max(180).describe("Longitude coordinate"), units: unitsSchema, exclude: oneCallExcludeSchema, });
• src/main.ts:700-703 (registration)

  Registration of the 'get-onecall-weather' tool using FastMCP server.addTool, specifying name, description, input schema, and execute handler.
  server.addTool({ name: "get-onecall-weather", description: "Get comprehensive weather data (current + 7-day forecast)", parameters: getOneCallWeatherSchema,