TypeScript MCP Server Boilerplate

Instructions

Implementation Reference

• src/index.ts:220-315 (handler)

  The implementation of the 'get-weather' tool, including tool registration, input/output schemas using Zod, and the handler function that fetches and processes data from the Open-Meteo API.

  server.registerTool(
      'get-weather',
      {
          description:
              '위도·경도 좌표와 예보 기간을 입력받아 현재 날씨와 일별 예보를 반환합니다. (Open-Meteo)',
          inputSchema: z.object({
              latitude: z.number().describe('WGS84 위도'),
              longitude: z.number().describe('WGS84 경도'),
              forecast_days: z
                  .number()
                  .int()
                  .min(1)
                  .max(7)
                  .optional()
                  .default(3)
                  .describe('예보 일수 (기본값: 3, 최대: 7)')
          }),
          outputSchema: z.object({
              content: z
                  .array(
                      z.object({
                          type: z.literal('text'),
                          text: z.string().describe('날씨 정보')
                      })
                  )
                  .describe('날씨 정보')
          })
      },
      async ({ latitude, longitude, forecast_days }) => {
          type WeatherResponse =
              | {
                    timezone: string
                    current: {
                        temperature_2m: number
                        relative_humidity_2m: number
                        weather_code: number
                        wind_speed_10m: number
                        precipitation: number
                    }
                    daily: {
                        time: string[]
                        temperature_2m_max: number[]
                        temperature_2m_min: number[]
                        precipitation_sum: number[]
                        weather_code: number[]
                    }
                }
              | { error: true; reason: string }
  
          const url = new URL('https://api.open-meteo.com/v1/forecast')
          url.searchParams.set('latitude', String(latitude))
          url.searchParams.set('longitude', String(longitude))
          url.searchParams.set(
              'current',
              'temperature_2m,relative_humidity_2m,weather_code,wind_speed_10m,precipitation'
          )
          url.searchParams.set(
              'daily',
              'temperature_2m_max,temperature_2m_min,precipitation_sum,weather_code'
          )
          url.searchParams.set('forecast_days', String(forecast_days))
          url.searchParams.set('timezone', 'auto')
  
          const res = await fetch(url.toString())
          const data = (await res.json()) as WeatherResponse
  
          if ('error' in data) throw new Error(data.reason)
  
          const DAY_NAMES = ['일', '월', '화', '수', '목', '금', '토']
          const { current, daily, timezone } = data
  
          const currentLines = [
              `현재 날씨 (${timezone})`,
              `  기온: ${current.temperature_2m}°C | 습도: ${current.relative_humidity_2m}% | 풍속: ${current.wind_speed_10m} km/h | 강수: ${current.precipitation}mm`
          ]
  
          const dailyLines = daily.time.map((date, i) => {
              const dayName = DAY_NAMES[new Date(date).getDay()]
              return `  ${date} (${dayName}): 최고 ${daily.temperature_2m_max[i]}°C / 최저 ${daily.temperature_2m_min[i]}°C, 강수 ${daily.precipitation_sum[i]}mm`
          })
  
          const text = [
              ...currentLines,
              '',
              '일별 예보:',
              ...dailyLines
          ].join('\n')
  
          return {
              content: [{ type: 'text' as const, text }],
              structuredContent: {
                  content: [{ type: 'text' as const, text }]
              }
          }
      }
  )