Top AI models can disappear fast, not just get expensive

Anthropic launched Fable 5, its new top Mythos-class model, on June 9. On June 12, the U.S. government issued an export control directive for national security reasons, and Anthropic removed Fable 5 and Mythos 5 for all customers to comply.

Other Anthropic models still worked. The stated concern was a narrow jailbreak that lets the model read a codebase and fix software flaws. Anthropic argued that other public models, including GPT-5.5, can do the same kind of work, and that defenders use this ability in normal security work every day.

For AI agent builders, the risk is not only token cost or rate limits; a key model can become unavailable with little warning because of regulation or geopolitics.