Inside the fight over Claude Mythos 5

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On Friday, the US Commerce Department gave Anthropic a 90-minute ultimatum: suspend all access to Mythos 5 and Fable 5 for any foreign national worldwide — including its own employees — or face formal export controls. Anthropic had spent the past week publicly promoting these models and had no practical option but to disable them entirely. Mythos 5 and Fable 5 share the foundation of Anthropic's Mythos Preview, which the company itself labeled too dangerous for public release. Mythos 5 was restricted to vetted government agencies and approved companies; Fable 5 had extra safeguards and was cleared for general use. A report suggesting those safeguards had failed gave the administration grounds to act. Anthropic executives reached the White House within 15 minutes of the initial 1pm ET government call. CEO Dario Amodei joined about 75 minutes later, speaking directly with Treasury Secretary Scott Bessent and Commerce Secretary Howard Lutnick, then traveled to Washington DC to push back on the directive. This sets a precedent for US government authority over frontier AI. If Commerce Department export controls can force AI companies to cut off all foreign nationals — including their own employees — the implications for international AI talent pipelines and global AI product access are severe.