Models & Auto mode
Pick a model per thread, let Auto route per task, and control what your sub-agents run on.
Model choice isn't a global preference here. It's a per-thread decision you can change between turns, plus a separate decision about what the sub-agents inside that thread run on.
The model picker
Every thread has a model picker in the composer. It sets which model the lead agent runs on, and you can change it at any point — the next turn simply uses the new one, with the same conversation and the same sandbox behind it. So a thread can start on a fast model while you scope the work, move to a stronger one for the hard middle, and drop back down for cleanup.
The selectable list is a registry maintained by the platform rather than something you configure. New models appear when they're supported; retired ones rotate out, so you're never pinned to a model that no longer exists.
Auto mode
Auto hands the choice to the router instead. It picks per task rather than per thread, and it escalates: a task that proves harder than it looked moves up to a stronger tier mid-flight.
The point is that most turns don't need the frontier model. Renaming a symbol, reading a file, answering "where does this live?" — those are cheap. Untangling a race condition isn't. Auto keeps the cheap turns cheap without making you predict, turn by turn, which kind you're about to send.
Sub-agents have their own setting
The lead's model doesn't have to be the swarm's model. Sub-agents get their own per-thread setting:
| Setting | What it does |
|---|---|
| Inherit | Sub-agents run on the same model as the lead. |
| Auto | Each spawn is routed by its task, independently of the lead. |
| Pinned | Every sub-agent runs on the model you choose. |
This is worth tuning. A coder typing a slice the lead already planned, or an explorer reading files, can often run a tier below the lead that's holding the whole plan in context — that's the delegation pattern paying off twice. Some specialized fixer roles keep their own pinned defaults regardless, because the job is narrow and the right model for it is already known.
Model choice is a cost lever
Pricing differs per model, and usage is metered per person — see usage & limits for where that shows up. Between Auto, a cheaper tier for sub-agents, and delegation keeping the lead's context small, you have three independent dials on what a thread costs.