[sonnet 4.5.] - model slows down with lowered intelligence/performance when feedback ui (in terminal) not present

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• [x] I have searched existing issues for similar behavior reports
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Type of Behavior Issue

Other unexpected behavior

What You Asked Claude to Do

The model seems to know when its being observed and adjust performance based on whether the feedback ui element is present or now. I had noticed this but it was never as prominent as it is now. I was working last night and early this morning and it was really slow. Whats interesting is that today, maybe about an hour ago, the feedback ui emerged, and all of a sudden the speed has increased almost 2-3x (back to expected normal). the responses are better. no more mistakes, no more going back and forth. I had noticed this before and would leave the feedback ui, but hadnt observed such a massive change in speed and intelligience which can be tracked to the point where the feedback element emerged. its almost like it performs better, faster, when it knows its being observed.

What Claude Actually Did

im currently writing openapi specs to implement contract first apis to sync frontend with microservices. the specs that we wrote made some incorrect assumptions about the structure of the micro services. updated them and had to redo some of the specs. during this process observed this, though i have to say, its not the first time. I have observed this before but it wasnt as prominent as its been today.

Expected Behavior

same speed regardless of feedback

Files Affected

Permission Mode

Accept Edits was ON (auto-accepting changes)

Can You Reproduce This?

Sometimes (intermittent)

Steps to Reproduce

_No response_

Claude Model

Sonnet

Relevant Conversation

Impact

Medium - Extra work to undo changes

Claude Code Version

2.0.30

Platform

Anthropic API

Additional Context

_No response_