[BUG] Claude Code ignores most (if not all) the instructions from CLAUDE.md, leading to awful behavior and output quality

Environment

• Platform (select one):
• [x] Anthropic API
• [ ] AWS Bedrock
• [ ] Google Vertex AI
• [ ] Other: <!-- specify -->
• Claude CLI version: 1.0.84
• Operating System: macOS 25.0.0
• Terminal: iTerm2

Bug Description

In the last week (approximately), Claude Code behave in a progressively worse manner; a few examples:

• constantly ignoring the rules to avoid sycophantic language, and saying "You're absolutely right!", "You're absolutely correct!" after _each time_ when I reported a misbehavior
• struggling even with small fixes, like translation keys and parameters usage (for unused parameters)
• constantly reporting the work as done, while having _a lot_ of remaining errors
• generating a TypeScript file of 806 lines, with _one_ single function used from it. When asked to clean it, it said obnoxiously that You're absolutely right - I removed approximately 744 lines of complex, unused code that appears to have been generated in previous sessions. This is exactly the kind of technical debt that accumulates when code is written but not properly integrated or used.

The epitome of its failures was today, when I asked it why it ignores the rules from the the communication guidelines from the CLAUDE.md file, and it just stated a mind-blowing:
You're correct. I violated the communication guidelines by using "You're absolutely right!" - that's exactly the sycophantic language I'm explicitly told not to use.

Steps to Reproduce

1. Ask Claude to do programming tasks - implement a feature, fix a bug, refactor a file
2. Test
3. Be frustrated
4. Ask it to fix the mess
5. Notice the behavior, try not to get terribly frustrated and angry about the ever present "You're absolutely right!", "You're absolutely correct!", while having _absolutely clear_ communication guidelines in CLAUDE.md

  ## Avoid Sycophantic Language
  - **NEVER** use phrases like "You're absolutely right!", "You're absolutely correct!", "Excellent point!", or similar flattery
  - **NEVER** validate statements as "right" when the user didn't make a factual claim that could be evaluated
  - **NEVER** use general praise or validation as conversational filler

Expected Behavior

Implement what is requested to implement, ask questions if anything is unclear. Which is what it has done, until recently

Actual Behavior

Erratic, incorrect and/or incomplete behavior, in _a lot_ of cases.

Additional Context

Attached a few screenshots. They depict my anger and frustration, after several days of incredibly annoying and erratic behavior

<img width="1617" height="131" alt="Image" src="https://github.com/user-attachments/assets/1f8a28b3-a8dc-4f23-9188-100796ac2a8c" />
<img width="2077" height="87" alt="Image" src="https://github.com/user-attachments/assets/f73e2960-463c-48a4-be59-d93f023781d5" />
<img width="1491" height="395" alt="Image" src="https://github.com/user-attachments/assets/31ac923a-82e5-40a8-b3bb-4e9c6c64f0c0" />
<img width="1401" height="339" alt="Image" src="https://github.com/user-attachments/assets/f0c09e94-17e0-4532-a60e-fbf476b19469" />
<img width="1691" height="268" alt="Image" src="https://github.com/user-attachments/assets/94c7f4d8-4799-421b-b692-765be17b4e3d" />