A warning from Amazon led the White House to shut down Anthropic’s Mythos model

Amazon's CEO raised the alarm about a jailbreak in Anthropic's Fable 5 model, triggering an unprecedented export control order and a fresh clash with the White House.

A warning from Amazon chief executive Andy Jassy, concerns about unauthorized Chinese access, and cybersecurity fears all reportedly led the Trump administration to cut off foreign access to Anthropic’s powerful new AI model, Fable 5.

According to multiple media reports, Jassy first raised concerns about the model with senior administration officials on Thursday after Amazon researchers used a series of prompts to get the Mythos-class model to provide information about cyberattacks that was supposed to be restricted.

It is unclear if Amazon was testing Fable for vulnerabilities in response to a White House request or if the company conducted the tests completely of its own accord. Politico quoted an unnamed source familiar with Amazon’s discussions as saying the government asked Amazon for feedback on the new Anthropic model.

An Amazonspokesperson previously told Fortune: “As a leading cloud provider that serves a large number of private and public sector customers, it’s not uncommon for governments to seek our counsel on potential security risks. When they occur, we don’t share the details of these discussions.”

Semafor also reported, citing unnamed sources, that the U.S. government suspected that a Chinese-linked group had already used the jailbreak Amazon discovered. But the publication said it was unclear how the government had arrived at this suspicion or what evidence they had to support it. And an Anthropic spokesperson told the publication that the White House did not raise Chinese access to Mythos in its conversations with the company, and that Anthropic prohibits access to its products from within China.

What followed were several calls between Anthropic CEO Dario Amodei and senior administration officials, according to Politico, during which Amodei argued the security bypass found by Amazon was narrow rather than a full jailbreak of the model’s safeguards.

A source familiar with Anthropic told Fortune the company was given 90 minutes to pull its newest model and was given no previous communication of a national security threat. 

Still, by Friday evening, the Commerce Department had stepped in to use national security export controls to bar Anthropic from distributing Fable 5 and its underlying model, Mythos 5, to foreign nationals, a category that includes people outside the U.S. as well as non-citizens working inside the country, including employees within Anthropic. Given the scope, the AI lab said it had no option but to disable both models for all users.

Now, according to the person familiar with Anthropic, senior technical staff are in DC to meet with White House officials. 

The move marks the first time the U.S. government has used export controls to halt access to a commercial AI model already widely used by the public. The unprecedented step has sparked concern from politicians around the world and intensified calls for sovereign AI, the idea that countries should control the AI models, infrastructure, and data that underpin critical technology, rather than depend on systems that can be restricted or withdrawn by a foreign government.

Critics have described the export controls as government overreach. AI policy expert Dean Ball, who briefly served in the Trump administration, said on X that he could not tell whether the move amounted to “lawfare against Anthropic in particular or extreme national-security hawkery,” adding that it was “simply cartoonish.” Ben Murphy, a non-resident fellow at the Institute for Progress, said the directive marked “another step on the balkanization of technology,” warning it could discourage AI labs from being transparent with the government about AI models in the future.

The decision to use export controls could also reshape how the government treats future AI releases more broadly, potentially signaling more government oversight into how powerful new AI models are rolled out. An administration official told Axios that the government does not view other models on the market as posing the same national security risk because they do not exceed the capability level Mythos has reached, and that any future model crossing that threshold would need to go through the government before release.

The episode also escalates a months-long standoff between Anthropic and the Trump administration, which earlier this year designated the company a “supply chain risk” for Pentagon contractors after Anthropic declined to accept contract terms allowing its models to be used for “all lawful purposes.” Anthropic cited concerns over autonomous weapons and mass domestic surveillance and is contesting that designation in court.

An escalating standoff

On Friday, Anthropic said in a blog post that US national security authorities had not identified specific concerns, but that the company understood the government believed it had become aware of a method of bypassing, or jailbreaking, Fable 5.

However, over the weekend, White House AI adviser David Sacks offered his own account of the standoff. In a post on X, Sacks said a highly credible, trusted partner of both Anthropic and the government had identified a jailbreak in Fable 5’s guardrails and that the administration asked Amodei to fix the issue or withdraw the model. According to Sacks, Amodei refused, leading the administration to issue the export control reluctantly. Sacks added that the administration hopes Anthropic will remediate the issue so that Fable can return to general release as soon as possible, and pushed back on suggestions that the move was connected to the earlier Pentagon dispute.

Sacks previously served as the administration’s AI and crypto czar and has repeatedly clashed with Anthropic, accusing the company of regulatory capture tactics rooted in what he has called fear-mongering about AI risk.

Senior White House officials also told Politico that the export controls were a last resort after officials spent hours asking Anthropic to work with them. The publication also reported that Treasury Secretary Scott Bessent told Amodei directly during one call that he was making a bad decision.

‘A wake-up call’ for Europe

The fallout of the decision has reverberated beyond Washington, sparking reactions from politicians around the world. In Europe, the shutdown has reignited calls for what officials describe as sovereign AI, the idea that countries should control the AI models, computing infrastructure, and data that underpin critical technology, rather than depending on systems that can be restricted or withdrawn by foreign governments.

Former French prime minister Édouard Philippe said the episode showed that AI is now critical infrastructure as essential as electricity or the internet, and that infrastructure controlled by others is infrastructure that others can unplug. Bruno Retailleau, a French 2027 presidential candidate, said the move should serve as a “wake-up call,” arguing that a nation that depends on others for its technology is a nation that can be unplugged overnight.

In the UK, MP Al Carns said British hospitals, companies, and researchers had been using Fable 5 before it was switched off, framing the episode as part of a broader pattern of lost technological leadership. Tom Tugendhat, a former UK security minister and MP, similarly argued that the incident shows sovereignty is now more about “code than cannons,” and criticized the UK’s regulatory approach for prioritizing safety over building competitive AI capacity.

For many politicians, the ban made clear how dependent European governments and companies have become on a small number of U.S. AI labs, and how quickly that dependence can become a political liability when access is disrupted, even temporarily.

This story was originally featured on Fortune.com