A blogpost from Hugging Face, a company that hosts open source AI models and leaderboards, has stirred up the AI world for two reasons.

First, the company said it had come under a cyber attack from a fully autonomous AI agent that swarmed its system with “tens of thousands of automated actions.” Experts have been warning that AI agents are quickly becoming capable enough to carry these sorts of autonomous attacks—but the Hugging Face hack appears to be among the first real world examples.

That disclosure would normally be news-worthy in and of itself. But what Hugging Face said it did next has received even more attention: the company fought AI with AI, using a Chinese-built open-source model to detect the attack and understand its scope.