Summary
- Anthropic is restoring access to its Claude Fable 5 and Claude Mythos 5 AI models after U.S. export controls that forced a June suspension were lifted at the end of the month.
- Fable 5 is returning globally on July 1, while Mythos 5, a less restricted variant of the same underlying model, is being reintroduced only to approved U.S. organizations following government review.
- The episode, triggered by an Amazon-discovered jailbreak that let Fable 5 generate exploit code, has spurred closer collaboration between Anthropic and U.S. agencies on model testing, threat sharing and standards for rating jailbreak risks.
Anthropic is restoring access to its two most advanced AI models after the U.S. government lifted the export controls that forced it to pull them last month.
The controls on Claude Fable 5 and Claude Mythos 5 were removed on June 30, the company said. Fable 5 returns globally on July 1 across Anthropic's platforms, while Mythos 5, which shares the same underlying model but carries fewer safety restrictions, is being restored to a set of U.S. organizations after government approval on June 26.
The freeze dated to June 12, when the government applied export controls, rules that limit which foreign nationals can access a technology, to both models.
Because the order took effect immediately and Anthropic could not verify users' nationality in real time, it suspended access for everyone rather than risk breaching the rule.
The trigger was a cybersecurity finding after Amazon researchers reported a way to bypass Fable 5's safeguards, a technique known as a jailbreak, prompting the model to identify software vulnerabilities and, in one case, produce code showing how one could be exploited.