What this is
x402 is 100% of the design: settlement after the gate, and a per-resolve meter on the registry's truth tools. 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.
The meter prices a resolve of the registry's truth tools (substance record, pathway status, compounding eligibility) per call; the reads on the hub page and the kit stay open.
The door
- GET /api — the paid call: without payment a
402offer (x402 v2, scheme exact, USDC on Base); with a payment signature the settled answer and a signed receipt. Onkind=order_intentthe door verifies the payment, runs the gate and creates the intent, and settles only on allow or require_rx: a deny answers HTTP 403 with its reason code and the rule-set version and is not charged. Onkind=resolvethe door settles and answers the metered resolve. The receive address of record and the facilitator credentials are set on the door by the operator's hand. - GET /x402/receipt/{nonce} — resolve a receipt, forever.
- GET /x402/jwks.json — the receipt signing key.
- GET /x402/settled.json — this zone's register: the receipts issued on this zone, with
family_settledbeside it for the three-zone total. - Order intents — created by
create_order_intenton the door at mcp.a2a-peptides.ai/mcp; the intent carries decision_id, reason_code and rule_set_version.
Receipts
Every receipt is signed. Order-intent receipts carry decision_id and reason_code; every receipt carries the notice; resolve receipts carry jurisdiction and rule_set_version when the tool takes a jurisdiction. Beside those: the amount and asset, the settlement transaction, the payer, the presentation identifiers on an order intent, and bsfrdp_d. A receipt resolves at its nonce for as long as the door stands.
A refused order intent is not settled and not charged. The deny comes back with its reason code and the rule-set version; nothing settles and no receipt of payment exists.