generated: '2026-08-06'
method: probed
source: https://athleticbrewing.com/api/ucp/mcp
docs: https://athleticbrewing.com/agents.md
description: >-
  Cross-cutting runtime semantics for the Athletic Brewing UCP/MCP commerce surface, read
  from the live tool schemas the endpoint returned and from the store's own published agent
  instructions. There is no hand-written developer guide behind this — every rule below is
  either a field in a fetched JSON Schema or a sentence in the store's /llms.txt,
  /agents.md or /robots.txt.
authentication:
  style: >-
    Two layers. Agent identity via a required meta.ucp-agent.profile URI on every
    tools/call. Buyer authorization via Shopify customer-account OpenID Connect with PKCE
    S256. tools/list and initialize are anonymous.
  see: authentication/athletic-brewing-authentication.yml
idempotency:
  supported: true
  mechanism: request-body metadata key
  parameter: meta.idempotency-key
  scope: complete_checkout
  required: true
  retention: not published
  evidence: >-
    "idempotency-key" appears in the required[] array of the meta object on the
    complete_checkout tool's inputSchema, described as "An idempotency key for completing
    the checkout." It is the only tool of the thirteen that requires one — the money-moving
    one. No other tool declares an idempotency parameter.
  gaps:
  - No published retention window or replay semantics.
  - create_cart and create_checkout accept no idempotency key, so a retried create can duplicate.
pagination:
  style: cursor
  applies_to: [search_catalog]
  parameters:
    cursor: catalog.pagination.cursor
    limit: catalog.pagination.limit
  limit_default: 10
  limit_minimum: 1
  limit_maximum: not published
  response_fields: not published in the input schema
field_expansion:
  supported: false
  note: >-
    No expand/fields/sparse-fieldset parameter in any tool schema. get_product exists as a
    separate deeper read instead of an expansion on search_catalog.
metadata:
  supported: true
  note: >-
    Every tool takes a top-level `meta` object (UCP agent profile, and the idempotency key
    on complete_checkout). Buyer context travels in catalog.context / cart.context and
    platform data in catalog.signals (dev.ucp.buyer_ip, dev.ucp.user_agent), both
    additionalProperties:true.
request_id_tracing:
  supported: true
  header: x-request-id
  example_shape: 'e1753002-5140-4a17-885c-758c066f04de-1786062897'
  note: Returned by the MCP endpoint on every response, alongside x-shopify-ucp-mcp-api-version.
versioning:
  style: dated protocol versions, negotiated at discovery
  current: '2026-04-08'
  also_supported: ['2026-01-23']
  advertised_at: https://athleticbrewing.com/.well-known/ucp
  response_header: 'x-shopify-ucp-mcp-api-version: 2026-04-08'
  mcp_protocol_version: '2025-06-18'
  see: lifecycle/athletic-brewing-lifecycle.yml
errors:
  envelope: JSON-RPC 2.0 error object
  shape: 'error: {code, message, data: {code, content, continue_url}}'
  rfc9457: false
  http_mapping: >-
    Protocol-level failures return a non-2xx HTTP status carrying a JSON-RPC error body —
    an unresolvable agent profile returns HTTP 422 with error.code -32001.
  see: errors/athletic-brewing-problem-types.yml
rate_limits:
  signalled: true
  published_numbers: false
  policy: The MCP endpoint is rate-limited per IP; agents must back off on 429.
  see: rate-limits/athletic-brewing-rate-limits.yml
currency_and_money:
  representation: minor currency units (integers)
  evidence: catalog.filters.price.min / .max described as "in minor currency units".
  currency_code: ISO 4217, passed as catalog.context.currency
  locale_fields:
    country: ISO 3166-1 alpha-2 (catalog.context.address_country)
    language: IETF BCP 47 (catalog.context.language)
human_in_the_loop:
  required_for: payment completion
  statement: >-
    Agents must not complete checkout, payment, or order placement without an explicit,
    contemporaneous human approval step. Stated in /llms.txt, /agents.md and /robots.txt.
x-evidence:
  fetched: '2026-08-06'
  probes:
  - url: https://athleticbrewing.com/api/ucp/mcp
    method: POST tools/list
    http_status: 200
  - url: https://athleticbrewing.com/llms.txt
    http_status: 200
  - url: https://athleticbrewing.com/robots.txt
    http_status: 200
  - url: https://athleticbrewing.com/.well-known/ucp
    http_status: 200