The Nvidia-led coalition aims to give defenders more open tools for testing, auditing and protecting AI models and agents.

Twenty-five companies signed a letter defending open models days after a Chinese AI helped Hugging Face survive a hack triggered by OpenAI.

Nvidia, Microsoft, Meta and 22 others signed an open letter defending open-weight AI, led by Jensen Huang's first tweet. OpenAI, Anthropic and Google didn't.

Letter explaining support comes amid rift over AI development philosophies and governance