AI Agent Performs Brain Surgery on a Mouse

Biotech startup Exin Therapeutics says an AI agent has performed brain surgery on a mouse with epilepsy, and the mouse recovered well. The company's co-founder and CEO shared the whole process online.

The team used Anthropic's Sonnet model and gave it a list of 19 gene therapy carriers, the mouse model, and a robotic arm with a camera. The goal was to reduce seizures. The AI picked the drug and the brain region, worked out coordinates from three papers, and injected 250 nanoliters of drug into the mouse's brain.

A vet watched the whole surgery. Every irreversible step needed human approval, and there was an emergency stop button. Human doctors opened the skull and stitched it up. The AI only handled the drug injection.

The company first wanted to use Anthropic's Opus 5.5, but that model refused once it saw biology-related content. It reasoned that being cut off mid-surgery with a needle left in the brain would be worse than never starting.