Tip: Know Fable 5's Safety Fallback Before Pinning It for Security/Bio Work

Anthropic·medium signal

Fable 5 routes flagged cyber, bio-chem, and model-distillation prompts to Opus 4.8 via built-in safety classifiers, so a session pinned to Fable 5 may silently downgrade on those topics. For legitimate security-research or red-team tasks, expect the fallback and validate which model actually answered rather than assuming top-tier capability throughout. Budget accordingly when benchmarking Fable 5 on security-adjacent agentic tasks.