[BUG] Every single attempt at reviewing my codebase triggers fall back to opus 4.8

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?

The preview is so restrictive it blocks code review of 3d image segmentation workflow app utilizing package deps such as cellpose and cupy. Need to relax the trigger that makes Fable 5 model fallback to Opus 4.8 or provide an exclude mechanism because your defaults are not working.

What Should Happen?

Claude code should not fall back to Opus 4.8 for every request.

Error Messages/Logs

❯ Review this entire codebase and flag every bug, security issue, and code quality problems you find. use workflow mode to investigate the whole repo and write code review analysis to md file in repo so I can review and create a plan to resolve any issues discovered.

● I'll start by mapping the codebase structure, then fan out a detailed review across the modules. Let me get the lay of the land first.

● Bash(ls -la && echo "---GIT---" && git rev-parse --is-inside-work-tree 2>/dev/null || echo "not a git repo")
  ⎿  total 0
     drwxrwxrwx 1 derekt derekt 4096 Jun  3 11:14 .
     drwxrwxrwx 1 derekt derekt 4096 Jun  6 13:33 ..
     … +6 lines (ctrl+o to expand)

● Fable 5's safety measures flagged this message for cybersecurity or biology topics. They may flag safe, normal content as well. These measures let us bring you
  Mythos-level capability in other areas sooner, and we're working to refine them. Switched to Opus 4.8. Send feedback with /feedback or learn more:
  https://support.claude.com/en/articles/15363606
  ⎿  Tip: You can configure model switch behavior in /config

Steps to Reproduce

Relax flags for code that is obviously not even remotely close to cybersecurity.

Claude Model

Other

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.170

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

WSL (Windows Subsystem for Linux)

Additional Information

_No response_