Mythos 5: The USA Partially Reopens to Anthropic, but Fable 5 Remains Unavailable

In recent days, the U.S. government has partially lifted the ban on Anthropic models, allowing the release of Claude Mythos 5 to over 100 American institutions among large companies and federal agencies. The public version, Fable 5, remains blocked with no restoration date.

This change comes from a letter by Commerce Secretary Howard Lutnick dated June 26, stating that "adequate safeguards are in place to allow certain trusted partners access to the Claude Mythos 5 model," justifying the decision with "significant progress" in discussions over the preceding two weeks.

The ban came into effect on June 12, when some export controls forced Anthropic to disable access to Mythos 5 and Fable 5 for all users, including the company’s non-U.S. employees. This was triggered by warnings from Amazon and other companies to the government (notably from Amazon CEO Andy Jassy to the Treasury) regarding the potential for jailbreak of models, along with fears of access to Mythos 5 by actors linked to China.

What Changes with the New Letter

Under the new agreement, no license is required to export, re-export, or transfer Mythos 5 to the entities listed in Annex A of the letter and their foreign employees, as well as to non-American employees of Anthropic. The company stated that the model "can be redeployed to a limited group of U.S. organizations that operate and defend critical infrastructure," adding that it is working to quickly restore access.

However, the letter never mentions Fable 5: Anthropic's more capable public version remains blocked to hundreds of millions of users. Sources close to the negotiations have reported that discussions aim to restore that access as well, with talks expected over the weekend, but without firm dates. Lutnick clarifies that "all other conditions of the June 12 letter remain in effect" and reserves "the right to reassess and modify the scope of licensing requirements" should circumstances change.

Before the ban, about 200 companies had access to Mythos through Project Glasswing, Anthropic's invitation-only cybersecurity program, including Apple, Google, Cisco, Nvidia, Microsoft, and JPMorgan Chase. On the same June 26, OpenAI also released GPT-5.6 in a limited mode, only to approved partners on a case-by-case basis: a parallel that seems to outline a new practice of the Trump administration for frontier models. During negotiations, CEO Dario Amodei has taken a backseat role to reduce friction with the government, following earlier direct contacts with Chief of Staff Susie Wiles and Treasury Secretary Bessent. Anthropic, which has privately filed for an IPO with a valuation over $900 billion, is also engaged with the government in developing a regulatory framework to handle similar cases in the future.