Anthropic pauses Fable 5 and Mythos 5 after export order

Anthropic suspended access to its Fable 5 and Mythos 5 models after receiving a U.S. export-control directive on Friday that ordered removal of access by any foreign national, whether inside or outside the United States.

The company received the directive at 5:21 p.m. ET and, to ensure compliance, disabled the two models for all users. Anthropic said other models, including Opus 4.8, are not affected.

Anthropic said the government did not provide written details and has expressed concern about a possible “jailbreak” method that could bypass Fable 5’s safety controls. The company wrote, “To date, the government has only given us verbal evidence of a potential narrow, non-universal jailbreak, which essentially consists of asking the model to read a specific codebase and fix any software flaws.”

The company described the reported issue as limited in scope and different from a “universal jailbreak” that would broadly defeat safeguards. The statement added, “We disagree that the finding of a narrow potential jailbreak should be cause for recalling a commercial model deployed to hundreds of millions of people. If this standard was applied across the industry, we believe it would essentially halt all new model deployments for all frontier model providers.”

Fable 5 and Mythos 5 were released several days before the directive and are built on top of Mythos Preview, a foundation model Anthropic said had identified thousands of software vulnerabilities.

Because the directive restricts access by foreign nationals regardless of location, Anthropic disabled the models entirely to avoid accidental noncompliance. The company did not disclose whether it received written mitigation instructions or a timeline for restoring access and said it is working to restore availability as soon as possible.

The firm reiterated in its statement, “We are complying with the government’s legal directive and are removing access to Fable 5 and Mythos 5 for all users.”