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

# Models

> Choose which model each Platform Agent tier uses for your organization.

In a [Platform Agent](/build/platform-agent) chat, people choose a tier, not a model. Admins decide which model each tier runs on in **Settings > Models**.

| Tier | Default model | Use it for |
| - | - | - |
| **Smartest** | Opus | Deepest reasoning. |
| **Balanced** | Sonnet | The best everyday default. |
| **Fastest** | Haiku | Quick, inexpensive tasks. |

## Change a tier's model

1. Open **Settings > Models**.
2. Next to a tier, open the model picker and choose any model from the [catalog](/learn/agents/models#available-models).

The change applies to your whole organization. A tier you haven't changed keeps using its default. People in chat see only the tier names, never the model behind them.

<Note>
  Tiers apply to Platform Agent chats. [Agents](/learn/agents/models) each use the model set on the agent.
</Note>