Jun 9, 2026
Anthropic Releases Claude Fable 5, Expands Mythos Access In an announcement on June 9, 2026, Anthropic published a blog post introducing Claude Fable 5 and Claude Mythos 5. The company released Claude Fable 5 as a generally available, Mythos-class model with guardrails for public use, while Claude Mythos 5 remains restricted to Anthropic-approved cyber defenders and critical infrastructure providers via Project Glasswing, according to VentureBeat and Anthropic's announcement. Anthropic's materials and reporting highlight that Fable 5 outperforms prior publicly available Claude models across software engineering, knowledge work, vision, and long-running tasks, and that more than 95% of Fable 5 sessions run without fallback to older models (VentureBeat; Anthropic blog). The company demonstrated Claude Fable 5 completing vision-only tasks such as beating Pokemon FireRed, per Engadget and Tom's Hardware. Anthropic routes prompts on cybersecurity, biology, chemistry, and distillation to Claude Opus 4.8 as a safety measure, per the announcement and coverage in CNET and VentureBeat. From today through June 22, Fable 5 is included on Pro, Max, Team, and Enterprise subscription plans at no extra cost, per Anthropic's announcement.