generated: '2026-07-19'
method: searched
source: >-
  https://facerealityskincare.com/llms.txt + Storefront MCP tool schemas +
  /.well-known/ucp
description: >-
  Cross-cutting runtime semantics for the Shopify-hosted Face Reality Skincare
  agent-commerce surface, captured from the store's published llms.txt, the live
  Storefront MCP tool schemas, and the UCP merchant profile. This is a Shopify
  storefront, not a bespoke REST API, so conventions reflect the Shopify/UCP
  agent-commerce model.
auth:
  style: oauth2
  detail: >-
    Shop/read tools on the Storefront MCP require no auth. Customer-account and
    checkout-completion flows use the Shopify Customer Account API OAuth 2.0
    Authorization Code + PKCE flow (see authentication/facerealityskincare-authentication.yml).
    Checkout completion always requires explicit human buyer approval.
pagination:
  style: cursor
  detail: >-
    search_catalog results are paginated; the response returns a
    pagination.cursor which is passed back to fetch additional pages. Initial
    results are limited to improve experience.
buyer_context:
  detail: >-
    Agents pass context.address_country (ISO 3166-1 alpha-2) and
    context.currency for accurate pricing, localization, and availability.
rate_limits:
  signaling: http-429
  detail: >-
    The MCP endpoint is rate-limited per IP. Clients must back off on 429
    responses. (See rate-limits family; no numeric quota is published.)
read_only_surface:
  detail: >-
    Unauthenticated read access is documented for product/collection data via
    /products/{handle}.json, /collections/{handle}/products.json,
    /search?q={query}&type=product, and /sitemap.xml.
error_envelope:
  style: jsonrpc
  detail: >-
    MCP errors follow JSON-RPC 2.0 error objects (e.g. code -32001 "UCP discovery
    failed" observed from /api/ucp/mcp without an agent profile). No RFC 9457
    problem+json surface is published.
crosslinks:
  authentication: authentication/facerealityskincare-authentication.yml
  scopes: scopes/facerealityskincare-scopes.yml
  mcp: mcp/facerealityskincare-mcp.yml
  llms: llms/facerealityskincare-llms.txt