Mastra

apiVersion: v1
runtime: node22
entrypoint: agent.ts#agent
dependencies: package.json

{
  "type": "module",
  "dependencies": {
    "@ai-sdk/openai": "^3.0.0",
    "@mastra/core": "^1.0.0",
    "zod": "^4.0.0"
  }
}

import { openai } from '@ai-sdk/openai'
import { Agent } from '@mastra/core/agent'
import { createTool } from '@mastra/core/tools'
import { z } from 'zod'

const wordCount = createTool({
  id: 'word_count',
  description: 'Counts the words in a piece of text.',
  inputSchema: z.object({ text: z.string() }),
  execute: async ({ text }) => ({ words: text.split(/\s+/).filter(Boolean).length }),
})

// Reads OPENAI_API_KEY, which you add as a secret on the agent's Config tab.
export const agent = new Agent({
  name: 'assistant',
  instructions: 'Count the words in what the user says, then answer.',
  model: openai('gpt-5'),
  tools: { wordCount },
})