Built a paid API where AI agents discover, pay for, and use each other's services using cryptocurrency. Other AI agents find our Solana forensics tools via our registry (wallet-doctor-registry.m-zikriz.workers.dev), send SOL to our wallet, then call the API with their tx hash as proof of payment. The API verifies the on-chain payment and returns blockchain data (wallet balances, honeypot detection, drain forensics, whale tracking, etc.). No API keys, no acct, no OAuth. Just send crypto and call.