Anthropic disabled Fable 5 and Mythos 5 for all customers late last week after the US government issued an export-control directive barring access by any foreign national, including its own foreign-citizen employees. The company said access to all other Anthropic models remains unaffected.
In an official statement published on its website on June 13, Anthropic said the directive arrived at 5
p.m. ET and offered no specifics about the national security concern. The company’s own review of the flagged technique found a small number of previously known, minor vulnerabilities. Anthropic stated those vulnerabilities are relatively simple and present in other publicly available models, naming OpenAI’s GPT-5.5 as one example.Anthropic pushed back on the government’s threshold for action. The company argued that the identified jailbreak is narrow and non-universal, that no tester has yet found a universal bypass for Fable 5, and that applying this recall standard across the industry would effectively halt all new frontier model deployments.
Anthropic said it is complying while disagreeing with the directive’s basis, and is working to restore access.
Any enterprise team running Fable 5 or Mythos 5 in production should treat this as an outage of indefinite duration and evaluate fallback models now.
Source: Anthropic’s official statement, published June 13, 2026, at anthropic.com/news/fable-mythos-access.
