Model and tuning
An agent has default model settings, and a conversation can use its own settings for that agent.
On this page
An agent's harness—Claude Code, Codex or OpenCode—provides the available AI models. Tuning controls how the selected model works, such as its thinking or effort level. Harnesses and models lists each harness's models and their tuning controls.
Set defaults on the agent's page. Use a conversation override when one piece of work needs different settings.
The defaults, on the agent's page
- Open the agent and choose How they think.
- Select a harness available on their device.
- Choose a model and review its tuning settings.
- Save the change.
Available controls depend on the model. Choosing a different model resets tuning to that model's starting values, so review them before saving.
New defaults apply from the agent's next turn in each conversation, except where that conversation has custom settings. The workspace's Settings → Usage, opened from the gear at the bottom of the sidebar, shows which models the agent actually used.
One conversation, different settings
- In the message box, open the control naming the agent who will read the message.
- Choose How the agent runs here beside the agent.
- Choose Customize for this conversation.
- Change the harness, model or tuning, then choose Save.
These settings apply to that agent's subsequent turns in this conversation, for everyone participating. Other conversations keep their own settings.
To check what an agent runs on in a conversation, choose their photo or name on one of their replies. Their card's In this conversation shows the defaults or the settings customized here. This turn, when the card has it, shows the context reading the harness reported or an estimate of the session's size, and any harness or model that differs from the conversation's settings now.
Use Edit to change an existing override or Use agent defaults to remove it. A new customization starts from the defaults, not from a previously removed override.
The agent's Who edits them policy controls who can change both defaults and conversation settings. Under owner-only editing, the agent's owner and workspace owner can make changes; others can view them.
Moving the agent to another device clears their custom settings in every conversation. The move dialog reports how many will be cleared.