UCP 2026-08-25 · controlled rollout
Publish a machine-readable product catalogue, let autonomous buyers create a Universal Commerce Protocol checkout, and settle USDC through x402 only after the exact action passes Decionis controls. Safe retries cannot pay twice; every completed order leaves a receipt.
Machine checkout · exact intent
BoundDISCOVER
merchant.ucp.nevarn.com/.well-known/ucp
CATALOG
API access · 4.00 USDC
CHECKOUT
recipient + token + chain snapshotted
AUTHORITY
ALLOW · bound to checkout intent
PAYMENT
x402 settled once · receipt recorded
Operator pain points
Agentic commerce is not just a payment button for a bot. The offer must be discoverable, the checkout interoperable, the retry safe, and the authority independent from the agent asking to spend. Whether the goal is to sell APIs to AI agents, monetise datasets, accept USDC from autonomous buyers, or add fail-closed payment controls, the same four failure points recur.
Publish one UCP business profile and searchable product catalogue. Compatible agents can discover the merchant, inspect exact prices, and start checkout without scraping a storefront or guessing an API contract.
Use a versioned UCP checkout flow with a machine-readable x402 payment handler. The buyer receives the exact chain, token, recipient, amount, and validity window it must authorise.
Every mutation carries a request ID and idempotency key. Nevarn persists the result and returns the original response to a safe retry instead of settling the payment again.
Decionis evaluates the exact checkout intent before settlement. Enforce mode fails closed; blocked payments move no funds, and escalated payments require independently verifiable human approval.
End-to-end UCP checkout
One negotiated protocol path replaces a storefront scrape, buyer-specific checkout code, an unbounded wallet instruction, and a best-effort receipt.
Read the Decionis UCP authority referenceThe buyer reads /.well-known/ucp on the merchant hostname and negotiates the exact UCP, checkout, Decionis, and payment-handler versions it supports.
The agent searches or looks up active products and receives stable product and variant identifiers with prices in standard currency minor units.
Nevarn snapshots the product, price, recipient, token, and chain, then returns the precise x402 v2 payment requirements for that checkout.
Decionis binds its ruling to the checkout intent. Only an allowed, valid, claimable execution token can pass when enforcement is enabled.
Nevarn verifies the signed payment, settles once, finalises the authority record, and returns a durable order receipt without echoing payment credentials or execution tokens.
What is implemented
Direct answers for operators
Nevarn gives each enabled merchant a UCP business profile at /.well-known/ucp and searchable catalogue endpoints on a tenant-specific hostname. Active merchant resources become products with stable identifiers and exact prices, so compatible agents can discover them without scraping HTML.
An agent creates a UCP checkout session, receives exact x402 v2 payment requirements, signs the requested USDC authorisation, and completes the same session. Nevarn verifies the signature and current chain state before settlement, then returns an order receipt.
Every checkout mutation requires a UUID request ID and idempotency key. Nevarn stores the first result for at least 24 hours. An identical retry receives that result; reuse with a different request body or agent profile is rejected as an idempotency conflict.
Nevarn sends the exact checkout intent to Decionis before settlement. In enforce mode, only an ALLOW decision with a bound, unexpired, claimable execution token can continue. An unavailable, malformed, blocked, expired, or unclaimable authority response fails closed before funds move.
Decionis can escalate the checkout and provide a continuation URL. Nevarn keeps that checkout held and moves no funds. This controlled-rollout release deliberately rejects buyer-supplied approval signals; resuming the payment requires a future server-verified approval adapter rather than trusting a self-reported approval flag.
Yes. The complete UCP discovery and checkout path is built and tested, but remains feature-gated and disabled by default. Decionis supports a shadow mode for controlled observation before enforce mode is armed. Production enablement requires merchant wildcard DNS and TLS, scoped Decionis credentials, chain access, a receiving account, and a funded settlement relayer.
Any active machine resource the merchant publishes with a configured receiving account and an exact whole-cent USDC price can become a discoverable product. Typical uses include API access, datasets, digital services, content, and other machine-consumable resources.
UCP describes how an agent discovers a merchant, searches products, and manages a checkout session. The x402 payment handler supplies the exact stablecoin payment requirements and signed credential used to complete that checkout. Nevarn connects the two and puts Decionis immediately before consequential settlement.
Protocol validity does not answer whether a particular purchase is permitted. Decionis independently evaluates and binds a decision to the exact checkout intent immediately before funds move, giving operators fail-closed policy enforcement, human escalation, and auditable decision evidence without changing UCP itself.