Anthropic Shuts Claude Fable 5 And Mythos 5 After US Government Order

Anthropic disabled its two most powerful AI models, Fable 5 and Mythos 5, for every customer after a federal export control order targeting foreign nationals.

Key Points:

Anthropic Halts Fable 5

The directive reached the company at 5:21 p.m. ET on Friday and cited national security powers it did not detail, the lab said. Officials wanted foreign nationals blocked, including its own overseas staff. To comply, Anthropic killed both models for everyone.

The company said it cannot separate foreign users from the rest of its base in real time, which made a worldwide shutoff the cleanest path. The order came from Commerce Secretary Howard Lutnick, drafted with input from other officials. Access to all other Anthropic models stayed intact.

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Fable 5 Jailbreak Disputed

The government's worry centers on a claimed way to slip past Fable 5's safeguards, according to the company. Anthropic said the technique amounts to asking the model to read a codebase and fix software flaws.

Engineers lean on that skill every day to defend live systems, the firm argued. It also noted that rival tools, including OpenAI's GPT-5.5, handle the same work without any bypass. Before launch, the lab said it had red-teamed Fable for thousands of hours and found no universal jailbreak.

Why The Order Matters

The move appears to be the first time a leading AI developer has taken a public model offline at federal request. That precedent could reshape how labs ship products and where they base their engineers.

Anthropic complied, then pushed back hard. Recalling a model used by hundreds of millions over one narrow flaw would, in its view, freeze new releases across the industry. The company apologized to customers and said it is working to restore access.

The shutdown lands days after a frantic stretch for the lab. Anthropic released Fable 5 on Jun. 9 as a guarded version of Mythos, which it previewed in April and kept inside a cybersecurity program called Project Glasswing. The rollout had already drawn complaints over token burn and a mandatory 30-day data retention rule before the order arrived.

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