What Do You Need to Know About Claude Fable 5?

Anthropic launched Claude Fable 5 (a public-facing Mythos-class model) on June 9, 2026; Fable 5 is gated by classifiers that reroute high‑risk queries (cybersecurity, biology, distillation) to Opus 4.8, while Mythos 5—with fewer safeguards—is reserved for vetted Project Glasswing partners for cybersecurity defense. The report outlines Fable 5's advanced capabilities (coding, long-running tasks, vision), pricing and data retention terms, and the implications for security teams, noting that the classifiers aim to reduce misuse but that the expanded capabilities raise the baseline risk of AI-assisted offensive activity.