[BUG] Fable 5 → Opus 4.8 fallback misfires on hobby-OS kernel
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?
Fable 5 → Opus 4.8 fallback misfires on hobby-OS kernel development. I’m developing my own operating system (QzOS/TOS, my own repo). Requests to audit my own VFS/filesystem code — plain defensive code review of code I wrote — triggered the Fable 5 safety fallback to Opus 4.8. The likely triggers are the words “kernel” (this is OS-kernel work, not ML-accelerator kernel work) and “security review” (reviewing my own code for bugs, not building exploits). Neither of the published fallback categories actually applies.
What Should Happen?
Claude should not trigged by simple word as “security review”. Request: tighten the classifier to distinguish OS-kernel development from ML-accelerator kernel development, and defensive code audit of one’s own repository from offensive tooling.
Error Messages/Logs
Steps to Reproduce
create new umbrella repo issue.
issue goal to analyze:
usr/src/sys/fs/vfs/vfs.c
usr/src/sys/fs/vfs/vnode_cache.c
issue approach
A scoped workflow audit, not an open-ended task: sweep the vfs and produce a ranked list of concrete findings — each then either fixed in a focused PR or filed as a specific sub-issue.
Claude Model
None
Is this a regression?
Yes, this worked in a previous version
Last Working Version
_No response_
Claude Code Version
Platform
Anthropic API
Operating System
Ubuntu/Debian Linux
Terminal/Shell
Other
Additional Information
_No response_