x402 — a paid call with a signed receipt

x402 — the office door. Every door in the portfolio answers a request for payment the same way: HTTP 402, the x402 standard, settled in USDC on Base, receipt signed and served forever. This is the office's own door, so a counterparty can prove the loop end to end with the principal's signature on the receipt. One resource: /api returns a signed statement of the office's current holdings summary. Price $0.01. Receipts at /x402/receipt/{nonce}, verified against /x402/jwks.json (kid mk-office-x402-2026-09). Settlement address and amount live in the 402 payload only. The office holds no cryptocurrency: the address is the rail's, the receipt is the office's. Facilitator: Coinbase Developer Platform. Network: Base mainnet.