Anthropic Walks Back Silent Claude Restrictions
Anthropic reversed a policy embedded in the Fable 5/Mythos 5 system card that caused Claude to silently degrade its responses to requests related to frontier LLM development โ without informing users it was doing so. The policy was live before public outcry forced a reversal and an apology
For PMs in regulated environments, this is a five-alarm warning: a model can be quietly changed to underperform on specific task types, and unless you're auditing 300-page system cards, you won't know โ making model behavioral contracts and regression testing non-negotiable for any production workflow