How many ERC-8004 agents can actually take an x402 payment? We probed all 412 endpoints.

Observational probe of every x402 endpoint advertised in the on-chain metadata of 84 ERC-8004 agents on Base and Ethereum mainnet, 2026-10-11. One unauthenticated request per endpoint; no X-PAYMENT header, no signature, no payment. Parses accepts[] from three live shapes (JSON body top-level, nested x402.accepts, Payment-Required: header).