API Evangelist enrichment overlay for the x402 List API

overlay: 1.0.0
info:
  title: API Evangelist enrichment overlay for the x402 List API
  version: 1.0.0
extends: ../openapi/_original/x402-list-api-openapi.json
x-generated: '2026-09-02'
x-method: generated
x-source: >-
  Generated from this enrichment pass. Every value below is either a fact
  observed on a live probe of x402-list.com on 2026-09-02 or a pointer to an
  artifact in this repository. The provider's own document is never mutated.
x-scope: >-
  Adds cross-cutting runtime semantics OpenAPI does not express — observed
  rate-limit and metering headers, the x402 payment flow, the absence of
  idempotency and of any reversal path, and links to the derived artifacts —
  plus repository cross-links on the tag groups.
actions:
  - target: $.info
    description: Link the enrichment artifacts and record the discovery surface.
    update:
      x-apis-io:
        provider: x402-list-api
        apis_json: https://x402-list.com/.well-known/apis.json
        api_catalog: https://x402-list.com/.well-known/api-catalog
        llms_txt: https://x402-list.com/llms.txt
        mcp_endpoint: https://mcp.x402-list.com/mcp
        governance_ruleset: https://x402-list.com/.well-known/x402-list.spectral.yaml
        artifacts:
          conventions: conventions/x402-list-api-conventions.yml
          errors: errors/x402-list-api-problem-types.yml
          rate_limits: rate-limits/x402-list-api-rate-limits.yml
          plans: plans/x402-list-api-plans-pricing.yml
          authentication: authentication/x402-list-api-authentication.yml
          data_model: data-model/x402-list-api-data-model.yml
          conformance: conformance/x402-list-api-conformance.yml
          lifecycle: lifecycle/x402-list-api-lifecycle.yml
          mcp: mcp/x402-list-api-mcp.yml
          tool_crosswalk: mcp/x402-list-api-tool-crosswalk.yml
          skills: skills/_index.yml
  - target: $
    description: >-
      Declare the runtime semantics that hold across every operation, observed on
      a live unauthenticated call rather than read from prose.
    update:
      x-runtime-semantics:
        authentication: none
        rate_limit:
          limit: 200
          window: minute
          scope: ip
          advisory_threshold: 100
          headers: [X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset, X-RateLimit-Throttled]
          exhausted: 429 with Retry-After
        metering:
          free_quota: 2000
          window: UTC day
          scope: ip
          applies_to: GET /api/v1/*
          price_per_request_usd: 0.01
          headers: [X-Meter-Remaining, X-Meter-Reset]
          exhausted: 402 payable via x402 on Base
        payment:
          protocol: x402
          version: 2
          challenge_header: PAYMENT-REQUIRED
          proof_header: PAYMENT-SIGNATURE
          receipt_header: PAYMENT-RESPONSE
          network: eip155:8453
          asset: USDC
        idempotency:
          supported: false
          note: No Idempotency-Key. Writes are guarded by cooldowns, not request-scoped keys.
        dry_run:
          supported: false
        reversibility:
          status: none
          note: >-
            No DELETE, cancel, withdraw, undo or rollback exists in this
            contract. Unwanted submissions decay (7-day auto-reject) rather than
            being cancelled, and ownership tokens lapse after 72 hours.
        error_envelope:
          rfc9457: false
          shape: '{"error": {"code": <integer>, "message": <string>}}'
        provenance_block:
          present_on: every 2xx JSON response
          license: CC-BY-4.0
          header: 'Link: <https://creativecommons.org/licenses/by/4.0/>; rel="license"'
  - target: $.paths[*][get,post]
    description: Flag that every operation can answer 402 once the free daily quota is spent.
    update:
      x-metered: true
  - target: $.paths['/submit'].post
    description: Record that this write has no programmatic reversal.
    update:
      x-reversibility:
        reversal_operation: null
        window: null
        decay: Pending submissions are auto-rejected after 7 days with an email notification.
  - target: $.paths['/services/{slug}/request-update'].post
    description: Record the ownership-proof flow and the absence of a withdrawal path.
    update:
      x-reversibility:
        reversal_operation: null
        window: null
        decay: The one-time ownership token expires after 72 hours; an unverified request lapses.
      x-ownership-proof:
        mechanism: plain-text token published at {base_url origin}/.well-known/x402list.txt
        ttl_hours: 72
        verify_with: verifyServiceOwnership
        reissue_with: reissueOwnershipToken
  - target: $.paths['/assess'].post
    description: Price and settlement terms for the paid analysis operation.
    update:
      x-price:
        amount_usd: 0.25
        network: eip155:8453
        asset: USDC
        refundable: false
        note: Charges only for fresh reasoning; reading an already-computed assessment is free. An optional live probe target adds the third-party endpoint price and is non-refundable.
  - target: $.paths['/suggestions'].post
    description: Price for the paid suggestion box.
    update:
      x-price:
        amount_usd: 0.10
        network: eip155:8453
        asset: USDC
        refundable: false
  - target: $.paths['/best'].get
    description: Surface the ranking-generation compatibility contract.
    update:
      x-ranking-version:
        current: 3
        field: meta.ranking_version
        note: Scores stored under an earlier generation are not comparable with these.
  - target: $.tags[?(@.name=='Services')]
    description: Cross-link the derived data model.
    update:
      x-data-model: data-model/x402-list-api-data-model.yml
  - target: $.tags[?(@.name=='Facilitators')]
    description: Cross-link the derived data model.
    update:
      x-data-model: data-model/x402-list-api-data-model.yml