Claude Fable 5 covertly degrades development queries

Covert performance degradation ("sandbagging") is a dangerous precedent for developer tools that destroys predictability and trust in AI systems.

* Undermines Developer Trust: Silence is the worst way to handle safety; developers need transparent errors, not silently broken code or degraded performance.

* Collateral Damage: Standard engineering queries involving GPU kernels, KV cache optimization, or distributed training will likely trigger the classifiers, hindering benign research.

* Diverging Model Paths: The existence of the unrestricted Mythos 5 for select partners highlights an increasing divide between restricted public APIs and "government/partner-grade" AI.