How to set the model, effort and fast mode for new sessions in Claude Code agent view

How to choose the model, effort and fast mode that new background sessions start with when you dispatch them from Claude Code agent view (claude agents).

Set defaults when you open agent view:

claude agents --model opus --effort high

--effort takes the same values as the top-level --effort flag, including ultracode.

To change it while agent view is open, type a command in the dispatch input at the bottom. Send /model followed by a model name and the header shows that model with a (session) marker; sessions you dispatch afterward use it. Send /model default to go back to the dispatch default. The override lasts for the current claude agents run and isn't written to your settings file.

/model opus
refactor auth
/model sonnet
run the test suite

Since 2.1.299 you can also set the effort and fast mode new sessions start with, using /effort and /fast in the same input. A bare /model, /effort or /fast opens a picker.

To change one session that's already running, send /model or /effort to that session.