[BUG] Opus 4.1 is a BUG

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?

Same code, let Sonnet 4.5 and Opus 4.1 fix the bug or create a new feature. Opus 4.1 will definitely fail! It will find the BEST way to fail you! and Generate a lot of hidden bugs which takes you hours to debug and fix!

What Should Happen?

Just use Opus 4.1 (regardless of the software or Terminal - anything). It will definitely fail you.

Error Messages/Logs

Totally not work.

Steps to Reproduce

1. Use a same project (My case, Java based Document Management System)
2. One for Opus 4.1, another for Sonnet 4.5
3. Ask for a new feature (ex. Let's create a page to show all the rejected invoices based on the existing invoices page)
4. Opus 4.1, create a rejected invoices page which cannot be compiled or generate something totally different from GUI, controller, services and repository and even MODAL to make the code can't even fit properly.
5. Sonnet 4.5, the right code with the right thing created in under 5 minutes.
6. Tata!

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.0.22

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

Please remove Opus 4.1 completely.