Claude Mythos 5

The restricted sibling of Claude Fable 5, sharing the same underlying Mythos-class model with fewer safeguards for vetted defensive-security and research use. Anthropic disclosed Mythos Preview on April 7, 2026, upgraded approved Project Glasswing users to Mythos 5 on June 9, suspended access under a U.S. export-control directive on June 12, and restored limited access for approved U.S. organizations on July 1 while it continues expanding the trusted-access program.