Anthropic says the US government issued an export control directive citing national security, ordering the company to suspend all access to its Fable 5 and Mythos 5 models for any foreign national, forcing it to disable the models for all customers. The directive reportedly stems from concerns about a "jailbreak" of Fable 5, though Anthropic maintains the technique only surfaced minor, previously known vulnerabilities that other publicly available models can also find. Access to the models was cut off the evening of June 12, 2026, with users redirected to use Opus 4.8 instead.

The US government has ordered Anthropic to suspend access to its Fable 5 and Mythos 5 AI models for all foreign nationals, citing unspecified national security concerns. The directive, received on June 12, 2026, requires immediate compliance, though the company disputes the uniqueness of the alleged vulnerabilities. Access to other Anthropic models remains unaffected.