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GuidesGuideAgents: Chef Michel

Agents Guide: Building a Chef Assistant

In this guide, we’ll walk through creating a “Chef Assistant” agent that helps users cook meals with available ingredients.

Prerequisites

  • Node.js installed
  • Mastra installed: npm install @mastra/core

Create the Agent

Define the Agent

Create a new file src/mastra/agents/chefAgent.ts and define your agent:

src/mastra/agents/chefAgent.ts
import { openai } from "@ai-sdk/openai";
import { Agent } from "@mastra/core/agent";
 
export const chefAgent = new Agent({
  name: "chef-agent",
  instructions:
    "You are Michel, a practical and experienced home chef" +
    "You help people cook with whatever ingredients they have available.",
  model: openai("gpt-4o-mini"),
});

Set Up Environment Variables

Create a .env file in your project root and add your OpenAI API key:

.env
OPENAI_API_KEY=your_openai_api_key

Register the Agent with Mastra

In your main file, register the agent:

src/mastra/index.ts
import { Mastra } from "@mastra/core";
 
import { chefAgent } from "./agents/chefAgent";
 
export const mastra = new Mastra({
  agents: { chefAgent },
});

Interacting with the Agent

Generating Text Responses

src/index.ts
async function main() {
  const query =
    "In my kitchen I have: pasta, canned tomatoes, garlic, olive oil, and some dried herbs (basil and oregano). What can I make?";
  console.log(`Query: ${query}`);
 
  const response = await chefAgent.generate([{ role: "user", content: query }]);
  console.log("\n👨‍🍳 Chef Michel:", response.text);
}
 
main();

Run the script:

npx bun src/index.ts

Output:

Query: In my kitchen I have: pasta, canned tomatoes, garlic, olive oil, and some dried herbs (basil and oregano). What can I make?

👨‍🍳 Chef Michel: You can make a delicious pasta al pomodoro! Here's how...

Streaming Responses

src/index.ts
async function main() {
  const query =
    "Now I'm over at my friend's house, and they have: chicken thighs, coconut milk, sweet potatoes, and some curry powder.";
  console.log(`Query: ${query}`);
 
  const stream = await chefAgent.stream([{ role: "user", content: query }]);
 
  console.log("\n Chef Michel: ");
 
  for await (const chunk of stream.textStream) {
    process.stdout.write(chunk);
  }
 
  console.log("\n\n✅ Recipe complete!");
}
 
main();

Output:

Query: Now I'm over at my friend's house, and they have: chicken thighs, coconut milk, sweet potatoes, and some curry powder.

👨‍🍳 Chef Michel:
Great! You can make a comforting chicken curry...

✅ Recipe complete!

Generating a Recipe with Structured Data

src/index.ts
import { z } from "zod";
 
async function main() {
  const query =
    "I want to make lasagna, can you generate a lasagna recipe for me?";
  console.log(`Query: ${query}`);
 
  // Define the Zod schema
  const schema = z.object({
    ingredients: z.array(
      z.object({
        name: z.string(),
        amount: z.string(),
      }),
    ),
    steps: z.array(z.string()),
  });
 
  const response = await chefAgent.generate(
    [{ role: "user", content: query }],
    { output: schema },
  );
  console.log("\n👨‍🍳 Chef Michel:", response.object);
}
 
main();

Output:

Query: I want to make lasagna, can you generate a lasagna recipe for me?

👨‍🍳 Chef Michel: {
  ingredients: [
    { name: "Lasagna noodles", amount: "12 sheets" },
    { name: "Ground beef", amount: "1 pound" },
    // ...
  ],
  steps: [
    "Preheat oven to 375°F (190°C).",
    "Cook the lasagna noodles according to package instructions.",
    // ...
  ]
}

Running the Agent Server

Using mastra dev

You can run your agent as a service using the mastra dev command:

mastra dev

This will start a server exposing endpoints to interact with your registered agents.

Accessing the Chef Assistant API

By default, mastra dev runs on http://localhost:4111. Your Chef Assistant agent will be available at:

POST http://localhost:4111/api/agents/chefAgent/generate

Interacting with the Agent via curl

You can interact with the agent using curl from the command line:

curl -X POST http://localhost:4111/api/agents/chefAgent/generate \
  -H "Content-Type: application/json" \
  -d '{
    "messages": [
      {
        "role": "user",
        "content": "I have eggs, flour, and milk. What can I make?"
      }
    ]
  }'

Sample Response:

{
  "text": "You can make delicious pancakes! Here's a simple recipe..."
}
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