Create Mastra

npm create mastra@latest

pnpm create mastra@latest
yarn create mastra@latest
bun create mastra@latest

npm create mastra@latest my-project --empty

npm create mastra@latest --no-example

npm create mastra@latest --template <template-name>

mkdir my-first-agent && cd my-first-agent
npm init -y

npm install -D typescript @types/node mastra@latest
npm install @mastra/core@latest zod@^4

{
  "scripts": {
    "dev": "mastra dev",
    "build": "mastra build"
  }
}

{
  "compilerOptions": {
    "target": "ES2022",
    "module": "ES2022",
    "moduleResolution": "bundler",
    "esModuleInterop": true,
    "forceConsistentCasingInFileNames": true,
    "strict": true,
    "skipLibCheck": true,
    "noEmit": true,
    "outDir": "dist"
  },
  "include": ["src/**/*"]
}

GOOGLE_GENERATIVE_AI_API_KEY=<your-api-key>

import { createTool } from "@mastra/core/tools";
import { z } from "zod";

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({
    output: z.string(),
  }),
  execute: async () => {
    return { output: "The weather is sunny" };
  },
});

import { Agent } from "@mastra/core/agent";
import { weatherTool } from "../tools/weather-tool";

export const weatherAgent = new Agent({
  id: "weather-agent",
  name: "Weather Agent",
  instructions: `
      You are a helpful weather assistant that provides accurate weather information.

      Your primary function is to help users get weather details for specific locations. When responding:
      - Always ask for a location if none is provided
      - If the location name isn't in English, please translate it
      - If giving a location with multiple parts (e.g. "New York, NY"), use the most relevant part (e.g. "New York")
      - Include relevant details like humidity, wind conditions, and precipitation
      - Keep responses concise but informative

      Use the weatherTool to fetch current weather data.
`,
  model: "google/gemini-2.5-pro",
  tools: { weatherTool },
});

import { Mastra } from "@mastra/core";
import { weatherAgent } from "./agents/weather-agent";

export const mastra = new Mastra({
  agents: { weatherAgent },
});

npm run dev