Anthropic released Claude Fable 5, its most capable public model, on June 9. On June 12, the U.S. government issued an export control directive suspending access to Fable 5 and Mythos 5 by any foreign national, citing national security authorities. Unable to filter access by nationality, Anthropic disabled both models worldwide. Fable 5 had been engineered to refuse responses in high-risk domains including cybersecurity, biology, chemistry, and model distillation, falling back to Claude Opus 4.8; early data showed at least 95 percent of sessions running entirely on Fable's own responses. Anthropic received the directive at 5:21 p.m. ET on June 12 in a letter from Commerce Secretary Howard Lutnick to CEO Dario Amodei, which named no specific technical detail. Anthropic believes the government learned of a jailbreaking method from a third-party company, involving asking the model to read a codebase and fix software flaws, surfacing only previously known, minor vulnerabilities. Anthropic argues comparable capability is available from other models including OpenAI's GPT-5.5, maintains no universal jailbreak has been found, and states its safeguards remain substantially stronger than any previously deployed model. The company is complying while openly disagreeing.