Models
Use any model with Letta Code
Letta Code is model-agnostic. Agents can use Claude, GPT, Gemini, or other supported models. Users can change an agent’s underlying model at any time, even mid-conversation.
Switching models
Section titled “Switching models”Use the /model command to switch models during a session:
> /modelThis opens a model selector with two categories:
- Supported - Pre-configured models with optimized settings
- All Available - All models available on your account, including custom BYOK (Bring Your Own Key) models
Use Tab to switch categories, arrow keys to navigate, and j/k to change pages.
You can also specify a model when starting Letta Code:
letta --model gpt-5-codexletta -m haikuToolsets
Section titled “Toolsets”Different models are trained to work best with different tools. For example, GPT-5 models are trained to use a patch-based editing tool, while Claude models work better with string-based edit tools.
Letta Code handles this automatically with toolsets - optimized tool configurations for each model family. When you switch models with /model, Letta Code automatically switches to the optimal toolset.
| Toolset | Optimized for |
|---|---|
| Default | Claude models (Anthropic) |
| Codex | GPT models (OpenAI) |
| Gemini | Google models |
Manual toolset override
Section titled “Manual toolset override”If you want to force a specific toolset:
letta --toolset codex> /toolset