OpenAI and Google Staff File Legal Brief Backing Anthropic

Rival AI Employees Unite in Unprecedented Legal Filing

In a striking display of cross-industry solidarity, more than 30 employees from OpenAI and Google DeepMind filed an amicus curiae brief on Monday supporting Anthropic's lawsuits against the U.S. Department of Defense. The filing, submitted in the Northern District of California, marks the first time employees of competing AI companies have formally intervened in a legal dispute involving a rival firm and the federal government.

The 37 signatories identify themselves as engineers, researchers, scientists, and other professionals from both companies. Among the most prominent names is Jeff Dean, Google's chief scientist and leader of the Gemini AI program, whose participation lends significant institutional weight to the filing. Other signatories include OpenAI security engineer Grant Birkinbine, Google Labs product director Kathy Korevec, and OpenAI technical staff member Leo Gao.

The Brief's Core Arguments

The amicus brief presents three interconnected arguments against the Pentagon's decision to designate Anthropic a supply chain risk. First, the signatories argue that Anthropic was correct to maintain its safety red lines regarding mass surveillance and autonomous lethal weapons. Second, they contend the government's actions constitute an "improper and arbitrary use of power that has serious ramifications for our industry."

Perhaps most pointedly, the brief argues that if the Pentagon was no longer satisfied with the agreed-upon terms of its contract with Anthropic, the agency could have simply canceled the contract and purchased the services of another leading AI company. Instead, the government chose to apply a supply chain risk designation historically reserved for foreign adversaries like Huawei and ZTE.

The filing warns that if allowed to stand, the designation will "undoubtedly have consequences for the United States' industrial and scientific competitiveness in the field of artificial intelligence and beyond" and will "chill open deliberation in our field about the risks and benefits" of AI deployment.

OpenAI's Complicated Position

The amicus brief places OpenAI employees in a particularly awkward position. The Defense Department finalized a competing deal with OpenAI within moments of designating Anthropic a supply chain risk, a move that many of the ChatGPT maker's own employees protested. OpenAI CEO Sam Altman publicly criticized the government's decision, stating on X that it was "a very bad decision" he hoped would be reversed, while acknowledging the timing of his company's Pentagon deal looked "opportunistic and sloppy."

OpenAI's own Pentagon contract includes language permitting the Department of Defense to use the AI system for "all lawful purposes, consistent with applicable law." However, OpenAI retains operational control through cloud-only deployment, cleared personnel monitoring, and termination rights if the government violates agreement terms. The distinction between OpenAI's approach of practical restrictions through infrastructure versus Anthropic's contractual restrictions has become a central debate in AI governance circles.

A Broader Movement Takes Shape

The amicus brief is part of a growing wave of industry opposition to the Pentagon's actions. A separate open letter titled "We Will Not Be Divided" grew from a couple hundred signatures on Friday to nearly 900 by Monday, with tech workers from Google, OpenAI, IBM, and other companies calling for clearer limits on how their employers work with the military. The letter was circulated independently of the court filing.

Major cloud providers have also signaled support. Google confirmed it will continue working with Anthropic on non-defense projects, Amazon affirmed continued support for civilian customers, and Microsoft reached a similar conclusion after a legal review. Together, these companies have invested billions in Anthropic and are unwilling to see the supply chain risk designation disrupt commercial partnerships.

What This Means for AI Engineers and Job Seekers

The cross-company amicus brief signals that AI safety principles may be evolving into a shared professional norm rather than a competitive differentiator. For engineers and researchers considering roles in the AI industry, the filing suggests that safety-focused companies may receive broader industry support when facing government pushback. The case could also establish important precedent for how AI companies negotiate with federal customers, potentially affecting hiring and contract work across the sector. The court is expected to rule on Anthropic's request for an emergency stay within the coming weeks.