ACP Integration

Agentic Commerce Protocol — freeform session metadata today, formal extension registration as the forward path.

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

What it is

An open-source specification for agent-driven commerce checkout, with a formal extensions mechanism. Supports session metadata that accepts arbitrary keys.

Tier A — Available today

ACP session metadata and checkout response links arrays accept arbitrary keys. A legalContext entry in session metadata, or alongside the existing terms_of_use / privacy_policy / return_policy entries in links, can be published today without coordination:

{
  "links": [
    { "type": "terms_of_use", "url": "https://example.com/terms.md" },
    { "type": "legal_context", "url": "https://example.com/.well-known/legal-context.json" }
  ],
  "legalContext": {
    "type": "sha256",
    "value": "0x7f83b165..."
  }
}

Tier B — Forward work

A formal Specification Enhancement Proposal registering legalContext as a first-class extension would give parsers a standardized handling across implementations.

Limitations

Without upstream registration, parsers must fall back to per-implementation conventions. The links array does not carry hash-verified integrity guarantees inherently — Level 2+ provability requires the structured legalContext entry alongside the link.

Relationship to existing ACP capabilities

The links array continues to serve as the Level 1 (informational) integration point — the terms are discoverable. The legalContext extension upgrades from informational URLs to hash-verified, integrity-protected references; the two compose.

Steward invitation

The ACP working group is invited to register legalContext as a first-class extension and publish guidance on integrity-bearing fields in checkout responses.