A2A X402 · SETTLEMENT AFTER THE GATE · 2026-09-20

A2A x402

Agent-to-Agent (A2A) + Model Context Protocol (MCP) hub for cosmetics.

AI agents for brands, manufacturers, retailers and distributors. Business to business.

The family rail of the a2a hubs: x402 settlement after the gate, and the receipts. An order intent settles in USDC on Base; the receipt is signed and carries the reason code and the rule-set version the gate returned.

x402
PROTOCOL · VERSION 2 · SCHEME EXACT
USDC
ASSET · BASE MAINNET (EIP155:8453)
1
GATE DECISION ON EVERY ORDER-INTENT RECEIPT · REASON CODE + RULE-SET VERSION
§01 · WHAT THIS IS

What this is

Settlement after the gate: an order intent created by the door settles here in USDC on Base; the receipt is signed and carries the reason code and the rule-set version the gate returned, so a settlement without a gate decision cannot exist. A refused order intent is not settled and not charged.

One rail serves every a2a hub; the register is per zone, with the family total beside it.

§02 · THE DOOR

The door

  • GET /api — the paid call: without payment a 402 offer (x402 v2, scheme exact, USDC on Base); with a payment signature the settled answer and a signed receipt. On kind=order_intent the door verifies the payment, runs the gate and creates the intent, and settles only on allow; a deny answers HTTP 403 with its reason code and the rule-set version and is not charged. On kind=resolve the door settles and answers the metered resolve.
  • GET /x402/receipt/{nonce} — resolve a receipt, forever.
  • GET /x402/jwks.json — the receipt signing key (EdDSA, kid a2ac-x402-receipts-2026-09).
  • GET /x402/settled.json — this zone's register, family total beside it.
  • Order intents — created by create_order_intent on the door at mcp.a2a-cosmetics.ai/mcp.
§03 · THE OTHER RAILS

The other rails

The four rail doors — agent-x402.ai · agent-mpp.ai · agent-ucp.ai · agent-acp.ai — and the front door a2a-pay.ai are GreenCore's. x402 is live; the Machine Payments Protocol (MPP), the Universal Commerce Protocol (UCP) and the Agentic Commerce Protocol (ACP) are built and dark until they can settle; nothing is advertised that cannot settle.

§04 · CONTACT

Contact

A person reads the form.

The form is the only human door on this surface.