AI API Cost Control: How x402 Prevents $47K Budget Overruns

A multi-agent system mistakenly burned $47,000+ in API costs. No hacker. No breach. Just bad infrastructure controls. Two AI agents were stuck in a recursive loop for 11 days, each one asking the other for clarification, each one convinced it was making progress. Nobody noticed until the invoice arrived. If you're building with LLMs today, this is not an edge case. It's a problem many teams will eventually face. This is what's referred to as an agent loop problem, and it exposes a deeper issue with AI infrastructure. These agents were handed API keys — the equivalent of giving them corporate credit cards — with no real-time spending governance. When the loop started, nothing existed at the infrastructure layer to stop it. The good news: Edge & Node has built an open-source system called ampersend that makes this type of failure impossible. With ampersend, every LLM call becomes a real USDC payment with spending limits enforced at the wallet level instead of application code. When the a