A customer of Anthropic, Legion, is suing the United States after it says it loses access to the company’s “Fable” AI model. Legion alleges that its access to the latest tool used for its development disappears immediately. According to Legion’s co-founder and CEO Arthur Rothrock, he decides to file the lawsuit because he believes the US government’s action creates a dangerous precedent. The reports describe Legion’s claim that the loss of access occurs suddenly, impairing its ability to continue work that relies on the Fable model. The sources also indicate that the lawsuit is framed as a challenge to the government’s role in restricting access rather than a dispute with Anthropic alone. The outlets do not provide additional details on the specific government measures involved, the timeline of events, or the legal arguments beyond Rothrock’s stated concerns. The case is presented as ongoing, with the focus on whether government actions affecting access to an AI model are lawful and what they mean for customers relying on such tools for development.