Claude Fable 5 is Anthropic’s newest general‑use Mythos‑class model, offering state of the art performance across software engineering, analysis, vision, and scientific research while using strict safeguards to prevent misuse. Claude Mythos 5 is the same underlying model but with certain restrictions lifted for vetted cybersecurity and life‑science partners, enabling advanced defensive and research applications. Both models aim to expand access to powerful AI capabilities while maintaining strong safety controls.