Amazon Warning Triggered Anthropic’s Shutdown of Claude Fable and Mythos Models

Amazon Chief Executive Andy Jassy’s conversations with US officials prompted the government to issue an order that led Anthropic to disable its Fable 5 and Mythos 5 models.

This came after company researchers reported that Fable 5 had been pushed to supply restricted cyberattack information.

What Caused the Anthropic Fable 5 and Mythos 5 Shutdown

Amazon is one of Anthropic’s largest backers, having invested billions of dollars. The firm’s report showed Fable 5 surfaced security bugs in at least four software programs when fed a specific set of queries. 

Jassy raised the security concerns with senior Trump administration officials. According to the Wall Street Journal, White House officials soon convened to map out a response.

Meanwhile, security researchers began stress-testing Amazon’s findings. Officials then pressed Anthropic to patch the flaws or pull the model, administration sources said.

They settled on barring foreign governments, firms, and individuals from the tool as the cleanest fix. President Trump approved the step, though he worried it could slow innovation, a senior White House official said.

“Jassy’s calls to administration officials were viewed by some as a general warning that quickly escalated into a wide Commerce Department ban on foreign users’ accessing Mythos and Fable, the people said. National Cyber Director Sean Cairncross and Commerce Secretary Howard Lutnick were involved in the conversations. The Commerce Department is in charge of export controls on critical technology,” the report read.

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Anthropic Pushes Back on the Cyber Risk

Anthropic argued that the flagged vulnerabilities are basic and that rival models can find them without any bypass.

“We disagree that the finding of a narrow potential jailbreak should be cause for recalling a commercial model deployed to hundreds of millions of people. If this standard was applied across the industry, we believe it would essentially halt all new model deployments for all frontier model providers,” the team said.

Anthropic apologized to customers for the interruption. The company called the order a likely misunderstanding and said it is working to bring access back quickly.

Meanwhile, the shutdown lands as Anthropic prepares a possible initial public offering (IPO). A prolonged outage could send users toward competitors while the company works to lift the ban.

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