Configuration
Models & thinking
Choose which Claude model your agents use and how hard they think before answering. Both are set in the composer and in Settings → Models.
Models#
Models are grouped by family — Opus (most capable), Sonnet (balanced speed and quality), and Haiku (fastest). Pick the newest in a family, or an older version for reproducibility.
| Family | Versions | Best for |
|---|---|---|
| Opus | 4.8, 4.7, 4.6, 4.5, 4.1 | The hardest tasks — deep refactors, tricky bugs, ambiguous specs. |
| Sonnet | 4.6, 4.5, 4.0 | Everyday work — a strong balance of speed, quality and cost. |
| Haiku | 4.5, 3.5 | Fast, cheap, routine edits and quick iterations. |
The selected model applies to new runs. You can switch models per message right from the composer.
Extended thinking#
Extended thinking gives the model more room to reason before it answers — deeper, but slower and slightly more expensive. Choose a budget:
| Level | When to use |
|---|---|
| Off | Routine work where speed matters most (default). |
| High | Non-trivial changes that benefit from planning. |
| XHigh | Complex, multi-file work or subtle logic. |
| Max | The gnarliest problems — maximum reasoning depth. |
Cost control
Lowering thinking and using a cheaper model for routine tasks are two of the built-in tips on the Usage screen — both can be applied in a click.