I’m pretty sure that switch has always been there, but turning it off doesn’t do what you want. It disables thinking entirely.
Opus 4.7 does not support disabling adaptive thinking (web, Claude Code). [1] Like the OP, I experienced similar issues and I'm glad that they brought back the ability to disable adaptive thinking in Opus 4.8.
[1] https://code.claude.com/docs/en/model-config#adaptive-reason...
> Opus 4.7 and later always use adaptive reasoning. The fixed thinking budget mode and `CLAUDE_CODE_DISABLE_ADAPTIVE_THINKING` do not apply to them.
> Opus 4.7 and later
The source of truth should be the API docs which make it clear 4.8 didn't bring back extended thinking: https://platform.claude.com/docs/en/about-claude/models/over...
Any UI settings probably just map to changing the effort nudge on adaptive thinking
Adaptive thinking supports effort, but it's a nudge instead of an actual token budget.
Why not use the pages that plainly state they don't support extended thinking: https://platform.claude.com/docs/en/build-with-claude/extend...
Thank you for pointing this out.