{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://adcontextprotocol.org/schemas/3.3.0-beta.1/core/definition-pin.json",
  "title": "Definition Pin",
  "description": "Seller-authored integrity pin over one third-party-published definition that a proposal's commercial_terms reference: a publisher-catalog format option, publisher-catalog placement, adagents.json collection, or data-provider signal. content_digest is the lowercase-hex SHA-256 of the RFC 8785 (JCS) serialization of the kind's closed projection of the published entry, defined normatively in docs/media-buy/specification.mdx#definition-pins. Pins live inside commercial_terms, so terms_digest covers the pin but not the definition it names: a published definition can change while terms_digest still verifies, and re-verifying the pin is what detects it. Request inputs never carry pins.",
  "x-added-in": "3.3.0",
  "type": "object",
  "discriminator": {
    "propertyName": "ref_kind"
  },
  "x-adcp-validation": {
    "verifier_constraints": {
      "pin_projection": "content_digest is computed over the published entry minus its kind's exclusion list, with the kind's named set arrays de-duplicated and sorted by JCS bytes",
      "on_violation": "REFERENCE_DEFINITION_CHANGED"
    }
  },
  "properties": {
    "ref_kind": {
      "$ref": "https://adcontextprotocol.org/schemas/3.3.0-beta.1/enums/definition-pin-ref-kind.json"
    },
    "reference": {
      "type": "object",
      "description": "Closed canonical identity of the pinned definition. Only the identity members below are permitted, so the same definition always has one reference value and pins are unique by (ref_kind, reference)."
    },
    "content_digest": {
      "type": "string",
      "pattern": "^[a-f0-9]{64}$",
      "description": "Lowercase-hex SHA-256 of the UTF-8 RFC 8785 serialization of the projected published entry. No algorithm prefix."
    },
    "source_version": {
      "type": "string",
      "minLength": 1,
      "maxLength": 255,
      "description": "Opaque version label of the source document the seller resolved when it computed content_digest, such as the document's catalog_etag. Informational and never dereferenced: verification compares content_digest, never source_version. It MUST NOT contain URLs, credentials, or fetch detail."
    }
  },
  "required": [
    "ref_kind",
    "reference",
    "content_digest"
  ],
  "oneOf": [
    {
      "required": [
        "ref_kind"
      ],
      "properties": {
        "ref_kind": {
          "type": "string",
          "const": "publisher_format_option"
        },
        "reference": {
          "type": "object",
          "properties": {
            "publisher_domain": {
              "type": "string",
              "maxLength": 253,
              "pattern": "^[a-z0-9]([a-z0-9-]*[a-z0-9])?(\\.[a-z0-9]([a-z0-9-]*[a-z0-9])?)*$"
            },
            "format_option_id": {
              "type": "string",
              "minLength": 1,
              "maxLength": 255
            }
          },
          "required": [
            "publisher_domain",
            "format_option_id"
          ],
          "additionalProperties": false
        }
      }
    },
    {
      "required": [
        "ref_kind"
      ],
      "properties": {
        "ref_kind": {
          "type": "string",
          "const": "publisher_placement"
        },
        "reference": {
          "type": "object",
          "properties": {
            "publisher_domain": {
              "type": "string",
              "maxLength": 253,
              "pattern": "^[a-z0-9]([a-z0-9-]*[a-z0-9])?(\\.[a-z0-9]([a-z0-9-]*[a-z0-9])?)*$"
            },
            "placement_id": {
              "type": "string",
              "minLength": 1,
              "maxLength": 255
            }
          },
          "required": [
            "publisher_domain",
            "placement_id"
          ],
          "additionalProperties": false
        }
      }
    },
    {
      "required": [
        "ref_kind"
      ],
      "properties": {
        "ref_kind": {
          "type": "string",
          "const": "publisher_collection"
        },
        "reference": {
          "type": "object",
          "properties": {
            "publisher_domain": {
              "type": "string",
              "maxLength": 253,
              "pattern": "^[a-z0-9]([a-z0-9-]*[a-z0-9])?(\\.[a-z0-9]([a-z0-9-]*[a-z0-9])?)*$"
            },
            "collection_id": {
              "type": "string",
              "minLength": 1,
              "maxLength": 255
            }
          },
          "required": [
            "publisher_domain",
            "collection_id"
          ],
          "additionalProperties": false
        }
      }
    },
    {
      "required": [
        "ref_kind"
      ],
      "properties": {
        "ref_kind": {
          "type": "string",
          "const": "data_provider_signal"
        },
        "reference": {
          "type": "object",
          "properties": {
            "data_provider_domain": {
              "type": "string",
              "maxLength": 253,
              "pattern": "^[a-z0-9]([a-z0-9-]*[a-z0-9])?(\\.[a-z0-9]([a-z0-9-]*[a-z0-9])?)*$"
            },
            "signal_id": {
              "type": "string",
              "maxLength": 255,
              "pattern": "^[a-zA-Z0-9_-]+$"
            }
          },
          "required": [
            "data_provider_domain",
            "signal_id"
          ],
          "additionalProperties": false
        }
      }
    }
  ],
  "additionalProperties": false
}