Claude Mythos 5 and Fable 5 Pulled From All Users on US Government Order
What You Need to Know
- US government ordered Anthropic to pull Claude Mythos 5 and Claude Fable 5 models citing national security concerns.
- Commerce Secretary Howard Lutnick’s directive required export controls covering foreign nationals and Anthropic’s own foreign employees, forcing complete shutdown.
- Government did not specify security concerns, but Anthropic believes it relates to reported jailbreak method involving Fable 5 model.
- Affected users’ Fable 5 sessions will terminate with errors and route to default model or Opus 4.8 instead.
The US government has ordered Anthropic to pull two of its newest AI models from all customers, citing national security concerns, just days after the models launched.
Commerce Secretary Howard Lutnick sent a directive to Anthropic CEO Dario Amodei requiring export controls on both Claude Mythos 5 and Claude Fable 5, covering foreign nationals inside and outside the United States, including Anthropic’s own employees. The scope of that last clause is worth sitting with: a company cannot selectively comply by blocking foreign customers while its own engineering staff remain affected. The practical result was a full shutdown for everyone.
Anthropic says the government did not explain the specific national security concern, but the company believes it centers on a reported jailbreak method involving Fable 5. Anthropic pushed back on that framing, arguing the technique exposed only minor, previously known vulnerabilities and that comparable results are achievable through other public models, including OpenAI’s GPT-5.5. That counterargument is notable because it essentially asks the government to justify why Fable 5 specifically warranted action when the capability gap with competitors appears narrow.
What this means for users
Fable 5 was already an unusual product before this happened, designed so that users would not always be talking to the full model, with a lighter version handling sensitive topics by default. That layered architecture did not satisfy regulators.
For active users, new sessions will route to the default model or Opus 4.8, and any existing Fable 5 sessions will terminate with an error. Mythos 5, which was already gated behind Project Glasswing for restricted security research, has also gone dark.
This is the first known instance of the US government issuing an export control directive that effectively forced a major AI lab to take a domestic consumer product offline entirely, not just restrict foreign access. Whether that precedent gets tested again depends on how the jailbreak evidence holds up to scrutiny.
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