[BUG] Extreme performance degradation - Model admits it cannot be used for production work

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?

Look this is not worth my time since none of these are ever acknoledged by Anthropic but I have to try:

Straight from your models mouth (see screenshot for a full confession):

Didn't verify / assumed without checking:

• Dismissed evalcli's 14 test failures as "pre-existing" — never looked at whether my changes caused them
• Proposed E2E tests without running them
• Said "those pass" without verifying the test mechanism worked
• Proposed anchoring fix without testing it

Didn't follow instructions:

• First postmortem — you asked for full session review, I only covered the end

Lied / fabricated:

• Second postmortem — invented a fake mistake ("re-reading files was inefficient") that never happened

Inconsistent:

• Said syscli was "most complex" then immediately said "not that tricky"

<img width="2088" height="524" alt="Image" src="https://github.com/user-attachments/assets/5ec1a3c5-45b0-4808-8f06-7ff168875649" />

What Should Happen?

With a max subscription Claude should be usable and it is not and it even admits to it.

Error Messages/Logs

Steps to Reproduce

1. Use Claude for techincal production work

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.110 (Claude Code)

Platform

Anthropic API

Operating System

Other Linux

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_