Anthropic Claude Mythos 5
Announced alongside Fable 5 and built on the same underlying model, Mythos 5 lifts safeguards in cybersecurity and life sciences — vulnerability discovery, drug design, biodefense screening — for a small set of vetted partners. Priced the same as Fable 5 at $10 per million input tokens and $50 per million output; use requires accepting a 30-day data-retention policy for safety monitoring.
Live only in limited release through 'Project Glasswing' to vetted cyberdefenders and infrastructure providers; in late June Anthropic was reported cleared to extend access to over 100 US institutions. Not generally available — Fable 5 routes restricted queries to Opus 4.8 instead.
Reality review pending — we publish the executive verdict after the launch has had time to meet the real world.
The first mainstream case of a frontier lab shipping the same model twice: a public guarded version and a gated unguarded version for defenders. For enterprises in security, pharma, or critical infrastructure, access to Mythos-class capability — and whether competitors have it — is becoming a procurement and risk question, not a research curiosity.