Claude Mythos 5 and Fable 5 are built on the same foundation as Anthropic’s Mythos Preview, which Anthropic dubbed too dangerous to publicly release. (The company’s warnings could be seen as genuine concern or more hype for their own model — or both.) Mythos 5 was made available to a select group of government agencies and companies, while Fable 5, which featured additional safeguards, was deemed “safe for general use.” But when a report indicated those guardrails may have failed, Anthropic’s dire warnings about Mythos falling into the wrong hands came back to haunt it.

A source familiar with the situation, who participated in the negotiations between Anthropic and the Trump administration, said the administration called the AI lab on Friday around 1pm ET and gave the company a 90-minute ultimatum to shut down access to Mythos 5 and Fable 5. If it didn’t, then the government would impose export controls on Anthropic by authority of the US Commerce Department.

The source said that Anthropic executives were talking to the White House within 15 minutes of that first call, confirming that CEO Dario Amodei joined the discussions about an hour and 15 minutes after that initial call. Amodei directly spoke with US Treasury Secretary Scott Bessent, Commerce Secretary Howard Lutnick, and National Cyber Director Sean Cairncross, in some cases more than once, the source confirmed.

Anthropic wrote in a release on Friday that the company believed that the government “believes it has become aware of a method of bypassing, or ‘jailbreaking’ Fable 5.” Rather than an existential threat, though, Anthropic said that the jailbreak in question was a “potential narrow, non-universal” one that was “shared with the government” by an entity the company declined to name. Moreover, Anthropic said the behavior wasn’t unique to Fable 5. “We have reviewed a report that we believe is the basis of the government’s directive and validated that the level of capability displayed there is widely available from other models (including OpenAI’s GPT-5.5),” Anthropic wrote.