specification: API Commons Tool Crosswalk
specificationVersion: '0.1'
provider: Google Pay
providerId: google-pay
generated: '2026-09-12'
method: derived
source: >-
  mcp/google-pay-mcp-tools-list.json (verbatim anonymous tools/list, 2026-09-12) bound against
  discovery/google-pay-walletobjects-v1-discovery.json (Google Wallet API v1 Discovery document,
  revision 20260911, fetched from walletobjects.googleapis.com)
note: >-
  Google publishes NO OpenAPI for any Google Pay surface. The only REST contract behind these
  tools that Google publishes machine-readably is the Google Wallet API Discovery document, so
  the `rest:` column carries Discovery method ids (walletobjects.<resource>.<verb>) rather than
  OpenAPI operationIds. Merchant-profile, integration-status and metrics tools sit on
  paydeveloper.googleapis.com, which serves no Discovery document and no OpenAPI (probed
  2026-09-12, /$discovery/rest?version=v1 -> 404, /openapi.json -> 404) — those are recorded as
  mcp_only, which is a real finding, not a gap in this crosswalk.
surfaces:
  mcp:
    url: https://paydeveloper.googleapis.com/mcp
    gated: false
    note: tools/list answers anonymously (HTTP 200); tool invocation requires OAuth 2.0.
  rest:
    contract: discovery/google-pay-walletobjects-v1-discovery.json
    format: Google API Discovery Document (not OpenAPI)
    base_url: https://walletobjects.googleapis.com/
    method_count: 99
    gated: false
  openapi:
    present: false
    note: no first-party OpenAPI published for Google Pay Web, Android, Wallet, or paydeveloper.
  graphql:
    present: false
crosswalk:
  - tool: list_pass_issuers
    category: wallet
    rest:
      - walletobjects.issuer.list
    binding: direct
    confidence: high
    note: >-
      Discovery method GET walletobjects/v1/issuer lists the same issuer set the tool describes
      as "all pass issuers registered in the Google Wallet business console".
  - tool: list_pass_classes
    category: wallet
    rest:
      - walletobjects.genericclass.list
      - walletobjects.loyaltyclass.list
      - walletobjects.offerclass.list
      - walletobjects.giftcardclass.list
      - walletobjects.eventticketclass.list
      - walletobjects.flightclass.list
      - walletobjects.transitclass.list
    binding: composite
    confidence: high
    note: >-
      One tool fans out across the seven per-pass-type class.list methods; the tool's passType
      parameter selects which. Each REST method takes issuerId, matching the tool's required arg.
  - tool: validate_pass_jwt
    category: wallet
    rest: []
    binding: none
    confidence: medium
    note: >-
      Validation-only. The Wallet REST surface has no validate method; the nearest REST behaviour
      is the insert/patch call rejecting a malformed class or object. Recorded here rather than in
      mcp_only because it validates the Wallet pass payload schema the REST contract defines.
mcp_only:
  - tool: search_documentation
    reason: Documentation retrieval over the Google Pay/Wallet docs corpus. No REST equivalent.
  - tool: list_merchants
    reason: >-
      Google Pay & Wallet Console merchant profiles. Served by paydeveloper.googleapis.com, which
      publishes no Discovery document or OpenAPI.
  - tool: create_merchant
    reason: Console merchant creation; paydeveloper.googleapis.com, no published REST contract.
  - tool: update_merchant
    reason: Console merchant mutation; paydeveloper.googleapis.com, no published REST contract.
  - tool: list_google_pay_integrations
    reason: Integration status/config for a merchant; no published REST contract.
  - tool: query_merchant_performance
    reason: Aggregated post-integration performance metrics; no published REST contract.
  - tool: query_merchant_error_metrics
    reason: Per-merchant error metrics; no published REST contract.
  - tool: list_principals
    reason: Merchant access control listing; no published REST contract.
  - tool: set_principal_role
    reason: Merchant access control mutation (destructiveHint true); no published REST contract.
  - tool: delete_principal
    reason: Merchant access revocation (destructiveHint true); no published REST contract.
rest_only_summary:
  count: 91
  note: >-
    91 of the 99 Google Wallet Discovery methods have no MCP tool — every object-level CRUD
    method (genericobject, loyaltyobject, eventticketobject, offerobject, giftcardobject,
    flightobject, transitobject insert/get/patch/update/list/addmessage), issuer insert/update/
    patch/get, permissions get/update, smarttap, media upload, and the jwt insert. The MCP server
    is a developer-console and documentation surface, not a pass-issuance surface; issuing passes
    still requires the Wallet REST API directly.
rest_only:
  - walletobjects.issuer.insert
  - walletobjects.issuer.get
  - walletobjects.issuer.update
  - walletobjects.issuer.patch
  - walletobjects.genericobject.insert
  - walletobjects.genericobject.get
  - walletobjects.genericobject.patch
  - walletobjects.genericobject.update
  - walletobjects.genericobject.list
  - walletobjects.loyaltyobject.insert
  - walletobjects.loyaltyobject.list
  - walletobjects.eventticketobject.insert
  - walletobjects.eventticketobject.list
  - walletobjects.offerobject.insert
  - walletobjects.offerobject.list
  - walletobjects.giftcardobject.insert
  - walletobjects.giftcardobject.list
  - walletobjects.flightobject.insert
  - walletobjects.flightobject.list
  - walletobjects.transitobject.insert
  - walletobjects.transitobject.list
  - walletobjects.permissions.get
  - walletobjects.permissions.update
  - walletobjects.jwt.insert
coverage:
  mcp_tools: 13
  mapped_to_rest: 2
  mcp_only: 10
  unmapped_validation_only: 1
  rest_methods: 99
  rest_methods_with_a_tool: 8
  rest_only: 91