Models
Use any model with Letta Code
Letta Code is model-agnostic - you can use Claude, GPT, Gemini, or other supported models, and switch between them 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. Your agent’s memory and context are preserved - only the underlying model changes.
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