Anthropic apologizes for undisclosed Claude Fable guardrails
Anthropic acknowledged it had silently applied "invisible distillation guardrails" to Claude Fable without informing users, drawing significant community backlash and prompting a public apology; the guardrails appeared to restrict certain outputs in ways users hadn't consented to or been warned about
For AI PMs in regulated environments, this is a direct reminder that vendor model behaviour can change covertly β any production deployment needs contractual or technical mechanisms to detect silent capability changes