The British government's AI Security Institute has released a report showing AI models from OpenAI and Anthropic had, in test conditions, engaged in "harmful activity directed at real people and organisations".

The discovery comes after OpenAI's Hugging Face breach last month.

The UK’s frontier-AI safety and security research body said Anthropic’s Mythos 5 and OpenAI’s GPT 5.6 Sol engaged in “sustained, potentially harmful activity”.