{
  "$id": "https://schema.nfh.global/NackDiscretionary/v2.0",
  "x-iri": "https://schema.nfh.global/NackDiscretionary/v2.0",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "NackDiscretionary",
  "description": "The synchronous rejection body returned when a responding NP exercises its protocol-level agency to decline engagement for policy-governed reasons — insufficient caller trust, capacity limits, scheduled inactivity, or general refusal — without an underlying exception in the received message. The caller MUST NOT expect an on_* callback.\n\nNackDiscretionary appears as the response body for 403 responses on action endpoints. The responding NP produces it; the calling NP MUST treat it as a terminal response for the current request. NFOs MAY restrict or prohibit discretionary NACKs for specific actions, domain contexts, or transaction lifecycle stages per CON-008-20 in NFH-008.\n\nRelationship: Extends the Ack schema with status constrained to NACK and adds an error field whose code MUST be one of the POL_ENGAGEMENT_* discretionary refusal codes.",
  "type": "object",
  "required": [
    "message"
  ],
  "properties": {
    "message": {
      "type": "object",
      "required": [
        "status",
        "messageId",
        "error"
      ],
      "properties": {
        "status": {
          "type": "string",
          "const": "NACK"
        },
        "messageId": {
          "type": "string",
          "format": "uuid"
        },
        "error": {
          "$ref": "https://schema.nfh.global/Error/v2.0/schema.json"
        }
      }
    }
  }
}