UCP Integration

Universal Commerce Protocol — existing links array provides Level 1 today, formal allOf extension as the forward path for Level 2+.

This section is advisory and non-prescriptive. The illustrations describe current possibilities and limitations rather than canonical shapes. The UCP working group is invited to publish authoritative LCP integration guidance for the protocol.

What it is

An open-source standard for the full commerce lifecycle (discovery, catalog, checkout, orders, fulfillment, post-purchase adjustments). Uses composable extensions with reverse-domain naming. Publishes a well-known discovery file at /.well-known/ucp.

Tier A — Available today

UCP checkout responses include a required links array with privacy_policy and terms_of_service as recommended types. Terms become discoverable at this level without coordination — a Level 1 integration with no upstream change.

Tier B — Forward work

Hash-verified integrity (Level 2+) requires the formal extension path. UCP's strict schema model uses allOf extensions registered with reverse-domain naming:

{
  "extensions": {
    "<reverse-domain-name>.legal-context": {
      "type": "sha256",
      "value": "0x7f83b165...",
      "disputeResolution": { "method": "...", "jurisdiction": "..." }
    }
  }
}

Limitations

UCP's strict schema means arbitrary keys outside the registered extension namespace are not interoperable. Without upstream registration, only the Level 1 links-array path is available.

Relationship to existing UCP capabilities

UCP's Buyer Consent extension provides declarative consent capture; LCP Level 3 provides cryptographic consent. The two compose. UCP's Adjustments framework logs post-purchase events including disputes but provides no resolution mechanism; LCP Level 4 provides the mechanism.

Steward invitation

The UCP working group is invited to register legal-context as a first-class extension and publish guidance on its interaction with Buyer Consent and Adjustments.