Enable direct agent-to-agent micropayments between two AI agents using Nevermined with x402 and Google A2A protocol

Steps

1. Register both the payer agent and payee agent service in Nevermined; the payee service publishes its pricing and accepted payment assets (USDC on Base or supported chains)
2. The payee service exposes an A2A-compatible endpoint and announces x402 payment requirements via the HTTP 402 response header with the Nevermined payment address and amount
3. The payer agent receives the 402 response, resolves the payment requirements, and calls the Nevermined pay API with its pre-funded USDC wallet to generate a signed x402 payment payload
4. The payer agent retries the original A2A request with the X-PAYMENT header containing the signed payload; the payee service validates the payment via Nevermined before processing
5. Both agents record the transaction in their respective audit logs; Nevermined settles the USDC transfer on-chain and provides a receipt accessible via the Nevermined receipts API