The Karpathy Loop
March 8, 2026: Andrej Karpathy dropped a 630-line Python script, aimed an AI agent at his own training code with a single metric to chase, and went to bed. Two days later the agent had run 700 experiments, found 20 genuine improvements, and cut training time by 11%. It also found a bug in Karpathy’s attention implementation that he had missed — not because the agent is smarter, but because it tried more things faster without getting bored after the 15th failed attempt. ...