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

# Agents

> Which agent runs a web, API, or mobile test, and how that choice is resolved.

Each test runs on one agent. Web tests default to **Fast-v2**. Mobile and API tests use **Intelligent**.

## How the agent is chosen

The run uses the first compatible agent in this order:

1. The per-test **Advanced** setting, when you set one while creating or editing the test.
2. The application's **Default Test Agent**.
3. The QA.tech default for that application type.

An agent stored on the test is skipped when it does not support the application type. The next candidate is used, or the default when none of the candidates fit.

## Web

| Agent                 | Model           | When to use                                      |
| :-------------------- | :-------------- | :----------------------------------------------- |
| **Fast-v2** (default) | GPT-5.6 Luna    | Quick and efficient. Recommended for most tests. |
| **Intelligent-v2**    | Claude Sonnet 5 | More capable. Recommended for complex tests.     |
| Fast                  |                 | Deprecated. Prefer Fast-v2 for new tests.        |
| Intelligent           |                 | Deprecated. Prefer Intelligent-v2 for new tests. |

Fast-v2 is the default for new web tests. Switch one test to Intelligent-v2 when it needs deeper reasoning. Most tests should stay on Fast-v2.

## Mobile

Mobile tests use **Intelligent**. The model routed for that agent depends on configuration, so this page names the agent only.

## API

API tests use **Intelligent**. That agent writes and runs validation code in a sandbox. It does not open a browser.

<CardGroup cols={3}>
  <Card title="Web" icon="globe" href="/build-tests/web">
    Suggested tests, email flows, and multi-user browser sessions.
  </Card>

  <Card title="API" icon="code" href="/core-concepts/api-testing">
    HTTP requests and assertions against an HTTPS API.
  </Card>

  <Card title="Mobile" icon="mobile" href="/test-features/mobile-app-testing">
    A cloud simulator or emulator runs your iOS or Android build.
  </Card>
</CardGroup>