> ## Documentation Index
> Fetch the complete documentation index at: https://lab.pollack.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Lesson 1: Your First Agent Task

> Create a file using an agent — set up, run, and verify

<Card title="Source Code" icon="github" href="https://github.com/markpollack/agent-client-tutorial/tree/main/01-create-file">
  `agent-client-tutorial/01-create-file`
</Card>

## What You'll Build

A Java program that asks an agent to create a file, then verifies the file was created. No Spring Boot required — just plain Java with the AgentClient API.

## Step 1: Set Up the Project

Create a Maven project with the Claude agent dependency:

```xml theme={null}
<dependencies>
    <dependency>
        <groupId>io.github.markpollack</groupId>
        <artifactId>agent-claude</artifactId>
        <version>0.25.0</version>
    </dependency>
</dependencies>
```

Or clone the tutorial repo:

```bash theme={null}
git clone https://github.com/markpollack/agent-client-tutorial.git
cd agent-client-tutorial/01-create-file
```

## Step 2: Understand the Code

Three lines do the real work:

```java theme={null}
// 1. Build the model — this is the provider-specific part
ClaudeAgentModel model = ClaudeAgentModel.builder()
    .defaultOptions(ClaudeAgentOptions.builder()
        .model("claude-sonnet-4-5")
        .yolo(true)
        .build())
    .build();

// 2. Create the client — this is the portable part
AgentClient client = AgentClient.create(model);

// 3. Run a goal
AgentClientResponse response = client.run(
    "Create a file named hello.txt with the content 'Hello from Agent Client!'"
);
```

Notice the separation:

* **Model construction** is provider-specific (you import `ClaudeAgentModel`)
* **Client usage** is portable (`AgentClient.create()` and `.run()` work with any model)
* **The goal** is a plain English string — describe *what*, not *how*

## Step 3: Run It

```bash theme={null}
./mvnw compile exec:java -Dexec.mainClass="HelloAgent"
```

## Step 4: Verify

Check that `hello.txt` was created:

```bash theme={null}
cat hello.txt
# Output: Hello from Agent Client!
```

## What Just Happened

1. `ClaudeAgentModel` found the Claude CLI on your system
2. `AgentClient.create(model)` wrapped it in the portable client API
3. `.run(goal)` sent your English instruction to the Claude CLI
4. The CLI created the file, and the response told you it succeeded

The agent did the same thing a developer would do — it created a file. The difference is you described *what* to do, not *how*.

## Next

[Lesson 2: Multi-Provider →](/docs/agent-client/tutorial/02-multi-provider) — Run this same task with Codex and Gemini without changing the client code.