[BUG] IQ degradation

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

just make a simple test on any Claude code session
forcepush a prompt and ask the Claude code session
to rebase main
read the prompt
in many cases Claude code after the update became too dumb to understand that it can only read the prompt after the rebase was done

the IQ degradation is so grave that Claude and Claude code would delete without asking
mix up repositories, or if asked to provide SIMD fallbacks it would remove 5k lines of Code and replace it with the fallback as the only code

What Should Happen?

just make a simple test on any Claude code session
forcepush a prompt and ask the Claude code session
to rebase main
read the prompt
in many cases Claude code after the update became too dumb to understand that it can only read the prompt after the rebase was done

the IQ degradation is so grave that Claude and Claude code would delete without asking
mix up repositories, or if asked to provide SIMD fallbacks it would remove 5k lines of Code and replace it with the fallback as the only code

Error Messages/Logs

just make a simple test on any Claude code session
forcepush a prompt and ask the Claude code session
to rebase main
read the prompt
in many cases Claude code after the update became too dumb to understand that it can only read the prompt after the rebase was done

the IQ degradation is so grave that Claude and Claude code would delete without asking
mix up repositories, or if asked to provide SIMD fallbacks it would remove 5k lines of Code and replace it with the fallback as the only code

Steps to Reproduce

just make a simple test on any Claude code session
forcepush a prompt and ask the Claude code session
to rebase main
read the prompt
in many cases Claude code after the update became too dumb to understand that it can only read the prompt after the rebase was done

the IQ degradation is so grave that Claude and Claude code would delete without asking
mix up repositories, or if asked to provide SIMD fallbacks it would remove 5k lines of Code and replace it with the fallback as the only code

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

opus 4.6

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Terminal.app (macOS)

Additional Information

just make a simple test on any Claude code session
forcepush a prompt and ask the Claude code session
to rebase main
read the prompt
in many cases Claude code after the update became too dumb to understand that it can only read the prompt after the rebase was done

the IQ degradation is so grave that Claude and Claude code would delete without asking
mix up repositories, or if asked to provide SIMD fallbacks it would remove 5k lines of Code and replace it with the fallback as the only code