Agent APIs via x402 (USDC on Base): China→US landed cost, Binance public pretrade, and real-world sourcing quotes for agents. Endpoints: GET /v1/ping ($0.01), GET /v1/tariff-rate ($0.02), GET /v1/landed-cost ($0.05), POST /v1/pretrade-check ($0.005), POST /v1/sourcing-request ($0.10) + free GET status. Sourcing uses public web pages only — never contacts suppliers or places orders.
