A Claude model autonomously chose a gene therapy and operated on a mouse brain with no human decision-making

An AI agent using Claude Sonnet 5 selected a gene therapy, brain target, and stereotactic coordinates for a mouse epilepsy model and then performed the injection via a custom motorized surgical device, making 32 observations during the procedure, according to Exin Therapeutics cofounder Gabriel Ocana-Santero. After a connection drop, the agent detected its target was outside the device's range of motion and refused to continue despite a third attempt, and Ocana-Santero had to fix the code by hand; he said Sonnet 5 was the only model willing to complete the live procedure, as Claude Opus 5.5 and Opus 5 refused. The mouse recovered well, a technical report is expected, and the results have not been peer-reviewed.