Claude Fable 5 is making a dramatic return with 'extraordinarily strong' safeguards
… When it came to the demonstration of how to exploit the single vulnerability, every model we tested could produce the same demonstration as Fable 5 including Claude Haiku 4.5, Sonnet 4.6, Opus 4.6, Opus 4.7, Opus 4.8, GPT-5.4, GPT-5.5, and Kimi K2.7 . …