AP2 Integration

This section is advisory and non-prescriptive. The illustrations describe current possibilities and limitations rather than canonical shapes. The AP2 working group is invited to publish authoritative LCP integration guidance for the protocol.

What it is

An open protocol for AI-agent-driven payments. Uses Verifiable Digital Credentials implemented as SD-JWT with Key Binding. Defines two mandate types, each with Open and Closed stages: Checkout Mandates (Open captures the user's authorization constraints before cart finalization; Closed captures authorization for a specific, finalized cart) and Payment Mandates (authorize a payment against a specific instrument, shared with the credential provider, networks, and merchant payment processor).

Tier A — Available today

LCP references travel alongside AP2 mandates in the transport-layer metadata of the protocol carrying the mandate (typically the agent-to-agent or agent-to-service transport). The transport metadata accepts arbitrary keys.

Tier B — Forward work

Embedding LCP inside the AP2 mandate itself — so the legal context travels through the mandate chain alongside the consumer's authorization — requires an upstream extension to the mandate schema.

Conceptual relationship

AP2 mandates capture what was authorized — the user approved this cart or delegated authorization for a yet-to-be-finalized one. LCP captures what terms govern the authorization — what the merchant offered, what dispute resolution applies, what obligations extend beyond payment. The two are complementary and travel together in a complete record:

AP2 Checkout Mandate (Closed): "User approved purchase of items X, Y, Z for $500"
LCP reference:                 "Terms governing this purchase are at hash 0x7f83...,
                                jurisdiction NY, AAA arbitration, 30-day return policy"

For Checkout Mandates in their Open stage (delegated authorization before cart finalization), the natural-language intent can be paired with machine-readable LCP constraints describing the legal framework within which the agent may act — extending the agent's authorization scope from financial constraints (spending caps, merchant categories) to legal constraints (acceptable jurisdictions, required dispute methods, contract duration).

Steward invitation

The AP2 working group is invited to publish guidance on LCP placement in transport-layer metadata and to consider an extension that allows LCP references to travel inside mandates themselves.