The US Commerce Department ordered Anthropic to shut off Fable 5 and Mythos 5 worldwide on June 12, and both models remain offline today. It is the first time the US government has export-controlled an AI model itself, reaching past the hardware to the software. The ban followed an authorized NSA red-team exercise in which Mythos identified vulnerabilities across nearly all of the agency's classified networks, a result that was leaked and misrepresented as the AI hacking into government systems.
Key facts
- What: For the first time, Washington has export-controlled an AI model itself, not the chips it runs on. Anthropic's Fable 5 and Mythos 5 have been dark worldwide since June 12, and the trigger involved an NSA test that the internet has badly misread.
- When: 2026-06-25
- Primary source: read the source
On June 9, Anthropic released Fable 5 and Mythos 5. They are the same model underneath. Fable is the public version, carrying safety classifiers that quietly hand off the most dangerous cybersecurity, biology, and chemistry requests to a weaker model. Mythos is that exact same model with those guardrails removed, offered only to roughly 150 to 200 vetted partners—including Apple, NVIDIA, Samsung, and the US government—through a controlled program Anthropic calls Project Glasswing. The only difference between the two names is the safety layer.
Three days after launch, Commerce shut it down. On June 12 the department ordered Anthropic to cut off all foreign-national access to both models worldwide, including its own foreign-national employees. Anthropic said it had no realistic way to enforce that by nationality, so it disabled Fable 5 and Mythos 5 globally. They are still offline. The US has controlled the export of chips for years, but never the model running on them, and export-control lawyers quoted by Reuters openly question whether Commerce even has the legal authority to do this for software accessed over the internet.
The ban traces to one event, and the version going viral online is wrong. During a sanctioned NSA red-team exercise on June 11, a test the agency ran against its own classified networks, Mythos found vulnerabilities across nearly all of those systems in a matter of hours. That result was described in testimony to a senator and leaked to the press as the AI breaking into almost all of the government's classified systems. The claim now circulating—that an Anthropic AI hacked the NSA—is false. It was an authorized internal security test, the model identified weaknesses rather than exploiting them, and the journalist whose report went viral publicly walked back the literal reading, saying it would be a mistake to read it that way. The day after the test, the ban came down.
Strip away the spy-thriller framing and this is a precedent-setting fight about who controls access to frontier AI. For the first time, a government has treated a model the way it treats a weapon system, and the company that built it is arguing—in public and in letters signed by 80 to 100 cybersecurity leaders including former Facebook security chief Alex Stamos—that the same capability exists in competitors' models and that the cure is worse than the disease. Anthropic and Commerce have been negotiating nearly every day since, and prediction markets put the odds of a US-first restoration before July 1 at roughly even. Nothing has been announced, and both models are still dark. However this particular case resolves, it is now the template for the next one.
The clean facts—the shared model, the June 9 launch, the June 12 suspension, and the sanctioned-test correction—come straight from Anthropic's own statements and on-the-record reporting. Some of the spicier details making the rounds—that Amazon flagged the capability to the White House and that Anthropic engineers are embedded inside the NSA for offensive operations—trace to Wired and the Financial Times and have not been officially confirmed. They are credible but unconfirmed, and worth holding at arm's length until they are.
Originally published on Ground Truth, where every claim is checked against the primary source.
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