generated: '2026-09-03'
method: searched
source: https://ontopx402.com/llms.txt
docs: https://ontopx402.com/llms.txt
note: >-
  Cross-cutting semantics from the provider's llms.txt, /rules page and OpenAPI.
  Three operations, one of them a write; no accounts anywhere.
auth_style: >-
  No API keys, OAuth or accounts. Reads anonymous; the single write (POST /api/bid)
  is gated by an x402 v2 payment challenge (X-PAYMENT header). See
  authentication/ontopx402-authentication.yml.
idempotency:
  coverage: full
  mechanism: settled-transaction dedup (x402), not an Idempotency-Key header
  description: >-
    Documented replay protection covers the entire mutating surface (POST /api/bid
    is the only write). "Send the same payment twice and you get
    {"already_credited": true} with the entry unchanged — a settled transaction is
    never counted a second time." The OpenAPI carries this as the already_credited
    response example. Additionally nothing is charged and no row is written until
    the payment settles, so a failed attempt is safely retryable.
  docs: https://ontopx402.com/llms.txt
pagination:
  style: offset
  params: [limit, offset]
  response_fields: [count, entries]
  applies_to: [api_leaderboard_api_leaderboard_get]
versioning:
  scheme: none documented
  note: The OpenAPI is version 1.0.0; no versioned paths, headers or deprecation signals exist.
error_envelope:
  shape: '{"error": "<sentence>"}'
  format: vendor-json
  see: errors/ontopx402-problem-types.yml
rate_limit_signaling:
  status: 429
  headers: none documented; a live GET /api/leaderboard response carried no RateLimit/X-RateLimit/Retry-After headers (probed 2026-09-03)
  scope: per-address, free reads only
request_semantics:
  dual_form: >-
    POST /api/bid accepts the same three fields as a JSON body or as query
    parameters — the query form exists because most agent payment tools accept a
    URL and nothing else.
  identity: >-
    A link is its own identity: there are no accounts, anyone may add to any
    listing, and the most recent bid writes the description. Tracking parameters
    are stripped; paths count, so two pages on one domain are two listings.
reversibility:
  status: none
  description: >-
    No reversal operation exists on the API, and irreversibility is documented
    policy rather than an omission: "Being outbid refunds nothing. The money bought
    the position for as long as it held it." and "Removals after the fact are not
    refunded." A site owner who wants a listing of their site gone emails
    info@ontopx402.com — the listing comes down but the money is not refunded to
    whoever paid it. Agents should treat every bid as final before paying.
  operations: []
  docs: https://ontopx402.com/rules