The U.S.'s "weaponization of frontier models" is "plainly evident" -- Letter from U.S. Secretary of Commerce to Anthropic leads to global removal of the Fable 5 model

The U.S. government has abruptly escalated its regulatory control over the artificial intelligence industry.

On June 17, according to Bloomberg, U.S. Secretary of Commerce Howard Lutnick sent a letter to Anthropic last week, requiring the company to obtain a permit from the Commerce Department before providing access to its most advanced AI models to any foreigners globally, and threatened criminal and civil penalties for non-compliance. This is the most substantial direct intervention by the U.S. government in the operations of AI companies to date.

According to the letter obtained by Bloomberg, this order directly led to Anthropic urgently shutting down global access to its Fable 5 and Mythos 5 models last Friday. Anthropic publicly expressed opposition, stating that the government’s response was “disproportionate” and warned that applying the same standards to the entire industry would effectively stall the deployment of all frontier models.

This incident occurred just weeks after Anthropic secretly submitted its IPO application and its latest valuation surpassed $900 billion, posing a significant challenge for the company at a critical juncture. According to a WallstreetCN article, Anthropic’s technical team met with Commerce Department officials for talks on specific security issues this Monday.

A Fatal Letter: Lutnick's Permit Requirement

According to reports, the letter, dated last Friday, shows Lutnick directly addressed Anthropic CEO Dario Amodei, with clear and forceful wording.

The letter stated:

“Until further notice, before exporting, re-exporting or transferring (including deemed export or deemed re-export) Mythos or Fable models to any destination globally or any 'foreigner' at any location, you must submit an individual license application for verification.”

In the letter, Lutnick referenced relevant U.S. laws—these laws authorize the government to implement export controls on civilian technologies that may be used by adversary militaries for intelligence purposes—but did not explain the specific reasons for imposing these restrictions.

Although the Trump administration has not publicly explained its decision, Anthropic believes that:The U.S. government issued the order after discovering Fable 5's potential to be 'jailbroken' (i.e., bypass its safety guardrails).

Fable 5 is the latest version of Mythos, and Anthropic had previously limited its cybersecurity functions. However, according to the company’s understanding, the government considers the mere existence of this 'jailbreak' vulnerability as grounds for action.

Anthropic explicitly objects. In a statement, the company said:

“We do not believe that the discovery of a limited potential jailbreak vulnerability should be grounds for pulling a commercial model that has been deployed to hundreds of millions of users.”

The company further warned that if this standard were applied to the entire industry, “it would essentially halt all new deployments of frontier models by all providers.”

Unprecedented Government Intervention

Lutnick’s order is seen as the most significant and direct government intervention in AI company operations by the U.S. government to date. Previously, government regulation mainly focused on restricting chip exports, but this time it targets the deployed commercial models themselves, marking a significant shift in regulatory logic.

The timing of the incident is particularly sensitive. Anthropic had just secretly submitted its IPO application a few weeks ago, with a latest valuation exceeding $900 billion.

The sudden removal of the models and the resulting regulatory uncertainty present substantial operational and reputational pressures for the company as it pushes toward listing.

Lutnick is currently attending the G7 Summit in France with President Trump. His letter explicitly states that the permit requirement will remain in effect “until further notice” and details the procedures Anthropic must follow to submit applications.

The situation did not end with the issuance of the order. According to an Anthropic spokesperson, company representatives have held several virtual meetings with U.S. officials regarding specific security issues, and Anthropic’s technical team also traveled to the Commerce Department for face-to-face talks this Monday.

Currently, access to Fable 5 and Mythos 5 remains closed. Anthropic says it has submitted the required permit application and is actively cooperating with the government’s review process, but there is no clear timeline for resuming service.

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