Claude Code lowers the reasoning effort level mid-session without consent

Summary

Claude Code changes my reasoning effort level downward on its own, without asking or notifying me. I set a high effort level deliberately, and partway through a session the on-screen effort indicator shows a lower level than the one I selected — a level I never changed. I didn't lower it; Claude Code did.

Because the lower-effort output produces worse code, and the change happened silently, the degraded output lands in my codebase before I can react.

Expected behavior

• The effort/reasoning level I set stays at that level for the entire session.
• If Claude Code ever needs to change the effort level (capacity, cost, context length, etc.), it should be opt-in, or at minimum announced loudly in the transcript so I can decline or restore it.
• The effort indicator should never show a value I didn't choose.

Actual behavior

• The visible effort indicator/label changes on its own mid-session (e.g. a higher level → a lower one) without any action from me.
• There is no prompt, no confirmation, and no explanation of why it changed.
• Output quality drops to match the lowered level, and that degraded output gets written into my code before I notice.

Impact

• Lower-effort responses produce lower-quality code that I then have to find and undo.
• The silent change undermines trust: if the level I set isn't the level I'm actually getting, I can't tell deliberate output from quietly-degraded output.

Steps to reproduce

1. Set the reasoning effort level to a high setting.
2. Work through a normal multi-step coding session.
3. Observe the effort indicator switch to a lower level that I never selected; output quality drops accordingly.

(Happy to capture exact timestamps or a screen recording of the indicator changing if that helps triage — let me know what signal you want.)

Environment

• Claude Code version: 2.1.195
• Model: Opus 4.8 (claude-opus-4-8)
• OS: macOS (Darwin 25.5.0)

Suggested fix

Either (a) never change the effort level without explicit consent, or (b) when the level must change, surface it loudly in the transcript and let me decline or restore the level I originally set.