Which model answers your message, and how to set your default

Every pane has a model picker above the input area. If it says Claude Sonnet, the next turn runs on Claude Sonnet. Change it mid-conversation and the following turn uses the new one.

How the picker decides what to show

When a pane opens, GPTree fills the picker with the first of these that is available to you:

1. The model the parent used, when the pane is a branch. Branches inherit so a comparison stays fair.
2. The model last used in this conversation.
3. The project's default model, if the project sets one.
4. Your account default model.
5. The default GPTree ships for everyone.
6. Auto.

Auto is a real choice, not a fallback: it picks a model per message based on what you asked for. If you want one model for everything, set a default instead.

Setting your account default

Open the AI Providers page and use the default model selector, or just tell the assistant in chat ("make Claude Opus my default"). Both write the same account setting, and new conversations start there.

One rule worth knowing: the models GPTree hosts are included with your plan, so your plan decides which ones you can pick. If you choose one your plan does not include, GPTree says so and leaves your default alone rather than saving a setting it cannot honor. Models you connect with your own API key are billed to you, so they are not plan restricted.

If your plan changes later and your saved default is no longer included, GPTree keeps you on the same provider and picks a model on that connection that your plan does allow. You stay with the provider you chose instead of being moved somewhere else quietly.

When your account allows only some AI providers

In Settings, then Knowledge sources, the "AI providers" section can limit your account to the providers you tick. With a limit set, the picker only lists models from those providers, your own API keys included, and Auto only chooses among them. A conversation that was using a model from a provider you then remove moves to the next choice in the list above that is allowed, or to Auto. If a message still names a model from a provider that is not allowed, GPTree does not send it: it tells you which providers your account allows, so you can pick one of their models or change the setting.

Checking what actually answered

Each assistant reply records the model that produced it, so you can look back at any turn and see which one wrote it. This matters most when you are comparing: a branch is only worth reading against another if you know what produced each side.