What
Choosing a model in the picker can now also set a per-session effort level and an "ultracode" flag, when the entry you pick carries a level. The switch runs through a hook-based confirmation that can block it or ask you to confirm first, and the picker no longer writes settings itself; the surrounding code does.
Details
- Effort and ultracode are only set for entries that come with a level; plain model entries behave as before.
Evidence
sessionEffort: IC(wr.level)
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
Names in the bundle/model
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Confirmed since
Anthropic's documentation has since written up /model, on All settings.
Cap the [effort level](/docs/en/model-config#adjust-effort-level) a session can use, leaving lower levels available. Any higher level runs at the cap instead, including one from `/effort`, the `/model` picker, `--effort`, [`CLAUDE_CODE_EFF…settings-reference see the edit
Added since
A small documentation edit on Agent SDK reference - TypeScript touched a line naming /model after this was published.
`effortLevel` accepts an [effort level](/docs/en/model-config#adjust-effort-level) name. It also accepts `"ultracode"`, which requests `xhigh` effort with [ultracode](/docs/en/workflows#let-claude-decide-with-ultracode) on. `applyFlagSetti…agent-sdk/typescript see the edit
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agrees
A small documentation edit on Agent SDK reference - TypeScript touched a line naming /model after this was published.