Anthropic · 2026-06-12 · major
Anthropic Suspends Claude Fable 5 and Mythos 5 — US national-security order
The US government issued a national-security export-control directive on June 12 ordering Anthropic to block access to Claude Fable 5 and Mythos 5 for every customer. Anthropic complied while disagreeing with the order.
Anthropic must disable both flagship models after a US export-control order tied to a narrow jailbreak finding.
What is it?
On June 12 at 5:21 pm ET, Anthropic received a US government directive ordering it to suspend access to Claude Fable 5 and Claude Mythos 5 for any foreign national, including its own foreign employees. To comply, Anthropic disabled both models for every customer worldwide. Its other Claude models, including Claude Opus 4.8, stay available.
How does it work?
The order cites national security with no public detail. Anthropic says it understands the trigger was a narrow potential jailbreak in Fable 5 — specifically when the model is asked to review a codebase for software vulnerabilities. Anthropic argues that a single narrow jailbreak should not force the recall of a model used by hundreds of millions of people, and says the process did not follow the kind of transparent, fair review it called for.
Why does it matter?
Every customer calling the Fable 5 or Mythos 5 API IDs sees requests fail. Teams need to roll back to Claude Opus 4.8 or an earlier model while Anthropic works to restore access. The directive also sets a precedent for how US export controls can be applied to a live commercial AI product over a single capability concern.
Who is it for?
Anthropic API customers, Claude developers