x402 Payment Flow

1. Agent makes a request → server responds 402 Payment Required with a payment payload

2. Agent pays via one of:

   • USDC on Base (chain ID 8453) via api.cdp.coinbase.com

   • USDT0 on Plasma (chain ID 9745) via Semantic facilitator

3. Agent retries with the X-Payment header → receives structured data

Payment options:

• USDC on Base (eip155:8453) — CDP facilitator

• USDT0 on Plasma (eip155:9745) — Semantic facilitator

Integration guide: https://github.com/rigoblock/agentic-operator/blob/main/AGENTS.md