Anthropic disables Fable 5 and Mythos 5 after US directive
Anthropic has removed access to Claude Fable 5 and Claude Mythos 5 after a US export-control directive targeting foreign-national access. The brief covers the shutdown scope, the government's stated jailbreak concern as described by Anthropic, Anthropic's objection, and what customers should watch next.
Anthropic has disabled Claude Fable 5 and Claude Mythos 5 for all customers after receiving a US government export-control directive that, according to the company, targeted access by foreign nationals to the two models. Anthropic said it received the directive at 5:21 p.m. ET on June 12 and that the order's practical effect was a full shutdown because it could not otherwise ensure compliance across users, regions, and employees. 1
The facts now
| Item | What Anthropic says |
|---|---|
| Event | US government issued an export-control directive to suspend access to Fable 5 and Mythos 5 by any foreign national, inside or outside the US. 1 |
| Timing | Anthropic says it received the directive on June 12 at 5:21 p.m. ET. 1 |
| Immediate customer effect | Anthropic says it is removing access to Fable 5 and Mythos 5 for all users, while other Anthropic models remain available. 1 |
| Stated government concern | Anthropic says the government has not given specific details, but the company understands the concern involves a method for bypassing, or jailbreaking, Fable 5. 1 |
| Anthropic's position | The company says the evidence it has seen points to a narrow, non-universal jailbreak and does not justify recalling a commercial model. 1 |
Why the shutdown is unusually disruptive
Fable 5 was only launched on June 9 as Anthropic's first Mythos-class model made available for general use. Anthropic described it as more capable than any model it had previously made generally available, with safeguards that routed certain cyber, biology, chemistry, and distillation-related requests to Claude Opus 4.8 instead. Mythos 5 used the same underlying model but had some safeguards lifted for a restricted group of cyber defenders and infrastructure providers. 2
That launch also changed Anthropic's data handling for this model class. For Mythos-class models, Anthropic required 30-day retention of prompts and outputs for trust and safety review, including on surfaces where some business customers previously used zero data retention. The company framed that policy as a way to detect jailbreak patterns and broader misuse that might not appear in a single request. 3
Reuters reported separately that a US official confirmed the Commerce Department had issued an export-control directive to suspend all access to Fable 5 and Mythos 5 by foreign nationals. Reuters also reported that AWS said Anthropic had asked it to revoke access to the models for "all users in all regions." 4
What Anthropic is disputing
Anthropic is not arguing that governments should have no power to block unsafe frontier-model deployments. Two days before the shutdown, it published a policy framework saying governments should have legal authority to block or deter deployments that pose catastrophic risk, provided the process is transparent, fair, clear, and grounded in technical facts. 5
Its objection is narrower: Anthropic says the government has provided only verbal evidence of a potential narrow jailbreak. The company says the demonstrated technique involved asking the model to read a codebase and fix software flaws, and that the resulting capability was already available from other public models. 1
The strongest line in the statement is this one: "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." Anthropic warned that applying the same standard across the industry could halt new frontier-model deployments. 1
What to watch next
The immediate question is whether Anthropic can restore access after giving the government more technical detail, or whether the directive becomes a precedent for restricting model access by nationality rather than by chip exports, cloud capacity, or end-use controls.
For customers, the practical answer is simpler: Fable 5 and Mythos 5 are unavailable for now. Anthropic says access to its other models is not affected, and it is working to restore the two suspended models as soon as possible. 1
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