NSA Confirms Mythos AI Use Despite Pentagon Blacklist

The National Security Agency (NSA) is reportedly deploying Anthropic’s advanced AI model, Mythos Preview, even as the Department of Defense (DoD) has labeled the company a “supply chain risk.” This situation highlights a significant internal contradiction. The conflict between Anthropic and the Pentagon dates back to early 2026.

In July 2025, Anthropic had signed a $200 million contract with the Department of Defense with explicit contractual restrictions prohibiting the use of its Claude AI for mass domestic surveillance and fully autonomous weapons systems.

The Pentagon-Anthropic Rift

The arrangement worked smoothly until January 2026, when Defense Secretary Hegseth issued a memo requiring “any lawful use” language across all DoD AI contracts,  effectively demanding Anthropic remove those safety guardrails.

Anthropic refused. In response, the Pentagon designated the company a “Supply-Chain Risk to National Security” in late February 2026, directing all contractors and suppliers doing business with the U.S. military to immediately cease commercial activity with Anthropic.

President Trump separately ordered all federal agencies to halt the use of Anthropic’s technology, with a 6-month phase-out window for systems already integrated.

Despite this sweeping ban, a new Axios report published April 19, 2026, revealed a striking contradiction.

The NSA, which itself operates under the Department of Defense, has been actively using Mythos Preview, Anthropic’s newest and most powerful AI model.

According to two sources cited by Axios, Mythos Preview is being used “more widely” within the NSA, with usage extending across other parts of the department.

Anthropic has tightly restricted access to Mythos, limiting availability to approximately 40 organizations due to concerns over its offensive cybersecurity capabilities.

Of those, only 12 have been publicly acknowledged, and the NSA is reportedly among the unnamed organizations granted access.

A central concern driving both the secrecy and controversy around Mythos is its advanced offensive cyber potential.

Anthropic itself has acknowledged fears that the model could supercharge cyberattacks if misused, a key reason why access has been so tightly controlled.

This makes the NSA’s deployment particularly significant: the agency is the nation’s premier signals intelligence and cybersecurity body, operating under U.S. Cyber Command.

In the U.K., the NSA’s counterparts reportedly access Mythos through the AI Security Institute, suggesting that allied intelligence communities are also quietly integrating the model.

Legal Battle Continues

Anthropic filed a lawsuit in March 2026 in San Francisco, characterizing the Pentagon’s supply-chain designation as “unprecedented and unlawful” and alleging violations of free speech and due process rights.

The case is ongoing, even as the military simultaneously argues in court that using Anthropic tools poses a national security threat while internally deploying those very tools.

On April 17, Anthropic CEO Dario Amodei met with White House Chief of Staff Susie Wiles and Treasury Secretary Scott Bessent to discuss the government’s use of Mythos, security protocols, and a potential roadmap for broader adoption by other federal departments.

The NSA’s quiet use of Mythos while the Pentagon battles Anthropic in court signals that operational necessity is overriding official policy within the U.S. intelligence community.

As AI capabilities advance, the gap between institutional bans and ground-level adoption is widening, raising serious questions about governance, oversight, and accountability in the deployment of advanced AI within national security agencies.

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