generated: '2026-09-02'
method: probed
source: >-
  https://urbanstems.com/agents.md (HTTP 200) for the stated policy; response headers observed on a
  live POST tools/list to https://274513-24.myshopify.com/api/ucp/mcp (HTTP 200) on 2026-09-02
name: UrbanStems rate limits
slug: urbanstems

limit_count: 0
limit_count_note: >-
  UrbanStems states that a limit exists but publishes no number. There is no rate-limit reference
  page, no quantified limit, no window and no burst anywhere on urbanstems.com. An honest zero: a
  qualitative rate-limit statement is present, a quantified limit is not.

documented_statement:
  quote: 'Respect rate limits. The MCP endpoint is rate-limited per IP. Back off on 429 responses.'
  source: https://urbanstems.com/agents.md
  scope: per-ip
  surface: https://274513-24.myshopify.com/api/ucp/mcp

limits: []

response_signalling:
  exhaustion_status: 429
  exhaustion_status_source: https://urbanstems.com/agents.md
  standard_headers_documented: []
  standard_headers_observed: []
  standard_headers_probed:
  - X-RateLimit-Limit
  - X-RateLimit-Remaining
  - X-RateLimit-Reset
  - RateLimit-Limit
  - RateLimit-Remaining
  - RateLimit-Reset
  - RateLimit-Policy
  - Retry-After
  observation:
    method: POST tools/list
    url: https://274513-24.myshopify.com/api/ucp/mcp
    http_status: 200
    date: '2026-09-02'
    result: >-
      No RateLimit-*, X-RateLimit-* or Retry-After header of any family was returned on a successful
      call. The agent has no remaining-budget signal and can only discover the ceiling by hitting it.

  non_standard_headers_observed:
  - name: shopify-complexity-score
    value_observed: '510'
    meaning: >-
      A per-request cost score, not a limit. It tells a client how expensive the call it just made
      was, but no budget, window or remaining balance is returned alongside it, so it cannot be used
      to pace requests without first learning the ceiling empirically.
  - name: shopify-complexity-score-v2
    value_observed: '51'
    meaning: A second-generation cost score on a different scale. Same limitation — cost without budget.
  - name: x-shopify-ucp-mcp-api-version
    value_observed: '2026-08-25'
    meaning: >-
      Echoes the UCP protocol version that served the request. Useful for version pinning; unrelated
      to rate limiting.
  - name: x-request-id
    value_observed: '<uuid>-<epoch>'
    meaning: Per-request trace identifier. Quote it when reporting a problem.
  - name: server-timing
    meaning: >-
      Carries processing/db durations plus edge, country, asn and requestID descriptors. Diagnostic,
      not budget.
  note: >-
    The substantive finding: this endpoint returns a COST signal and no BUDGET signal. An agent is
    told what it spent and never what it has left.

storefront_surface:
  scope: https://urbanstems.com read-only JSON routes (/products/*.json, /collections/*/products.json)
  documented: false
  note: >-
    UrbanStems documents these routes for agents in /llms.txt but states no limit for them; the
    rate-limit sentence is scoped to the MCP endpoint only.

gaps:
- No numeric limit, window or burst published.
- No RateLimit-* or X-RateLimit-* response headers emitted on success.
- No Retry-After documented for the 429 the provider tells agents to expect.
- A complexity/cost score is returned with no corresponding budget or remaining balance.