Anthropic released Claude Fable 5, a Mythos-class model with conservative safeguards that excels at long-context reasoning, software engineering, vision, knowledge work, and life-science research. A restricted-lifted variant, Claude Mythos 5, is available to vetted cyberdefense partners under Project Glasswing. Both are priced at $10 per million input tokens and $50 per million output tokens and lead benchmarks across multiple domains.

• Stripe used Fable 5 to migrate a 50-million-line Ruby codebase in one day, a job that would've taken a team two months
• Fable 5 and Mythos 5 cost $10/million input and $50/million output tokens, under half the previous Mythos Preview price
• Mythos 5 matched or beat expert scientists across all protein-engineering steps in a blind test, yielding nine drug candidates now under investigation
• Cybersecurity safeguards on Fable 5 silently reroute sensitive queries to Opus 4.8 in under 5% of sessions, while Mythos 5 drops those restrictions for vetted cyberdefense partners under Project Glasswing

Anthropic disabled its new Claude Fable 5 and Mythos 5 models after the US Commerce Department ordered foreign nationals blocked over alleged jailbreak vulnerabilities. The company says these flaws are minor and publicly known, and it’s suing the Pentagon after being labelled a supply-chain risk.

• Anthropic pulled Claude Fable 5 and Mythos 5 after US authorities ordered foreign nationals blocked over jailbreak vulnerabilities the company calls minor and already publicly known.
• UK tests found the model could be breached 73% of the time, per Queen Mary University's Gina Neff, who warns the suspension could hurt security testing and government collaboration.
• Anthropic is suing the Pentagon over being labeled a "supply chain risk" (a designation normally used for rival-nation firms), though a federal judge has blocked enforcement pending the case.
• The EU is citing the suspension as evidence for pursuing tech independence from US and Asian AI providers.