Nearly 40 employees from OpenAI and Google have submitted an amicus brief supporting Anthropic’s lawsuit against the US government. The lawsuit challenges the constitutionality of the government’s decision to designate the AI firm as a supply-chain risk. The legal fight highlights escalating tensions over the Pentagon’s use of AI in military technologies.

The list of employees included Jeff Dean, Google’s chief scientist and the lead for Gemini. On Tuesday, Microsoft also filed an amicus brief in support of Anthropic’s lawsuit.

Amicus briefs are legal submissions filed by parties not directly involved in a case but who possess relevant
expertise that may assist the court.

The “supply-chain risk” designation prevents military contractors from using Anthropic’s technologies, including its Claude model, which has reportedly already been integrated into some Pentagon workflows.

The tag is typically applied to foreign companies that the US government considers to be potential national security risks.

The AI start-up drew the label after maintaining two red lines around the acceptable military use of its technology — domestic mass surveillance and fully autonomous weapons systems.

In their filing, the engineers from OpenAI and Google argue that the Pentagon’s decision to blacklist Anthropic “introduces unpredictability in our industry that undermines American innovation and competitiveness”.

The engineers added that it could also “chill professional debate on the benefits and risks of frontier AI systems and the various ways those risks can be addressed to optimise the technology’s deployment”.

Microsoft backed Anthropic’s request for a temporary restraining order against the Pentagon order, arguing that its determination should be paused while the court ​considers the case.