Lightning Labs has introduced pi402, an extension for the Pi coding agent that enables it to pay for AI inference with bitcoin over the Lightning Network. This payment method is final and irreversible, eliminating the need for accounts, buyer-side API keys, and cards. With pi402, coding agents can pay for AI inference on a pay-per-token basis, allowing for precise pricing and minimizing the risk of chargebacks. This approach matches the product's characteristics, as AI inference is an irreversible process that consumes energy and resources, making it more suitable for a payment rail like bitcoin that provides finality and certainty.