On June 9, 2026, Anthropic released Claude Fable 5, which was described as the most capable AI model...

A paragraph buried in Fable 5’s 319-page system card revealed the model would silently downgrade its responses for certain AI development work—without telling users.

A paragraph buried in Fable 5's 319-page system card revealed the model would silently downgrade its responses for certain AI development work — without telling users.