ワークフローステップとしてのツール/エージェント

npm install @ai-sdk/openai @mastra/core 

import { openai } from '@ai-sdk/openai'
import { Agent } from '@mastra/core/agent'
 
// Create an agent that explains weather reports in a conversational style
export const weatherReporterAgent = new Agent({
  name: 'weatherExplainerAgent',
  model: openai('gpt-4o'),
  instructions: `
  You are a weather explainer. You have access to input that will help you get weather-specific activities for any city. 
  The tool uses agents to plan the activities, you just need to provide the city. Explain the weather report like a weather reporter.
  `,
})

import { createTool } from '@mastra/core/tools'
import { z } from 'zod'
 
interface GeocodingResponse {
  results: {
    latitude: number
    longitude: number
    name: string
  }[]
}
interface WeatherResponse {
  current: {
    time: string
    temperature_2m: number
    apparent_temperature: number
    relative_humidity_2m: number
    wind_speed_10m: number
    wind_gusts_10m: number
    weather_code: number
  }
}
 
// Create a tool to fetch weather data
export const weatherTool = createTool({
  id: 'get-weather',
  description: 'Get current weather for a location',
  inputSchema: z.object({
    location: z.string().describe('City name'),
  }),
  outputSchema: z.object({
    temperature: z.number(),
    feelsLike: z.number(),
    humidity: z.number(),
    windSpeed: z.number(),
    windGust: z.number(),
    conditions: z.string(),
    location: z.string(),
  }),
  execute: async ({ context }) => {
    return await getWeather(context.location)
  },
})
 
// Helper function to fetch weather data from external APIs
const getWeather = async (location: string) => {
  const geocodingUrl = `https://geocoding-api.open-meteo.com/v1/search?name=${encodeURIComponent(location)}&count=1`
  const geocodingResponse = await fetch(geocodingUrl)
  const geocodingData = (await geocodingResponse.json()) as GeocodingResponse
 
  if (!geocodingData.results?.[0]) {
    throw new Error(`Location '${location}' not found`)
  }
 
  const { latitude, longitude, name } = geocodingData.results[0]
 
  const weatherUrl = `https://api.open-meteo.com/v1/forecast?latitude=${latitude}&longitude=${longitude}&current=temperature_2m,apparent_temperature,relative_humidity_2m,wind_speed_10m,wind_gusts_10m,weather_code`
 
  const response = await fetch(weatherUrl)
  const data = (await response.json()) as WeatherResponse
 
  return {
    temperature: data.current.temperature_2m,
    feelsLike: data.current.apparent_temperature,
    humidity: data.current.relative_humidity_2m,
    windSpeed: data.current.wind_speed_10m,
    windGust: data.current.wind_gusts_10m,
    conditions: getWeatherCondition(data.current.weather_code),
    location: name,
  }
}
 
// Helper function to convert numeric weather codes to human-readable descriptions
function getWeatherCondition(code: number): string {
  const conditions: Record<number, string> = {
    0: 'Clear sky',
    1: 'Mainly clear',
    2: 'Partly cloudy',
    3: 'Overcast',
    45: 'Foggy',
    48: 'Depositing rime fog',
    51: 'Light drizzle',
    53: 'Moderate drizzle',
    55: 'Dense drizzle',
    56: 'Light freezing drizzle',
    57: 'Dense freezing drizzle',
    61: 'Slight rain',
    63: 'Moderate rain',
    65: 'Heavy rain',
    66: 'Light freezing rain',
    67: 'Heavy freezing rain',
    71: 'Slight snow fall',
    73: 'Moderate snow fall',
    75: 'Heavy snow fall',
    77: 'Snow grains',
    80: 'Slight rain showers',
    81: 'Moderate rain showers',
    82: 'Violent rain showers',
    85: 'Slight snow showers',
    86: 'Heavy snow showers',
    95: 'Thunderstorm',
    96: 'Thunderstorm with slight hail',
    99: 'Thunderstorm with heavy hail',
  }
  return conditions[code] || 'Unknown'
}

import { createWorkflow, createStep } from '@mastra/core/workflows/vNext'
import { weatherTool } from '../tools/weather-tool'
import { weatherReporterAgent } from '../agents/weather-reporter-agent'
import { z } from 'zod'
 
// Create workflow steps from existing tool and agent
const fetchWeather = createStep(weatherTool)
const reportWeather = createStep(weatherReporterAgent)
 
const weatherWorkflow = createWorkflow({
  steps: [fetchWeather, reportWeather],
  id: 'weather-workflow-step1-single-day',
  inputSchema: z.object({
    location: z.string().describe("The city to get the weather for"),
  }),
  outputSchema: z.object({
    text: z.string(),
  }),
})
  .then(fetchWeather)
  .then(
    createStep({
      id: "report-weather",
      inputSchema: fetchWeather.outputSchema,
      outputSchema: z.object({
        text: z.string(),
      }),
      execute: async ({ inputData, mastra }) => {
        // Create a prompt with the weather data
        const prompt = 'Forecast data: ' + JSON.stringify(inputData)
        const agent = mastra.getAgent('weatherReporterAgent')
        
        // Generate a weather report using the agent
        const result = await agent.generate([
          {
            role: "user",
            content: prompt,
          },
        ]);
        return { text: result.text };
      },
    }),
  );
 
weatherWorkflow.commit();
 
export { weatherWorkflow };

import { Mastra } from '@mastra/core/mastra'
import { createLogger } from '@mastra/core/logger'
import { weatherWorkflow } from './workflows/interop-workflow'
import { weatherReporterAgent } from './agents/weather-reporter-agent'
 
// Create a new Mastra instance with our components
const mastra = new Mastra({
  vnext_workflows: {
    weatherWorkflow,
  },
  agents: {
    weatherReporterAgent,
  },
  logger: createLogger({
    name: "Mastra",
    level: "info",
  }),
})
 
export { mastra }

import { mastra } from "./";
 
const workflow = mastra.vnext_getWorkflow('weatherWorkflow')
const run = workflow.createRun()
 
// Start the workflow with Lagos as the location
const result = await run.start({ inputData: { location: "Lagos" } })
console.dir(result, { depth: null })