{
  "id": "UBL-SR-33",
  "country": "EU",
  "syntax": "ubl",
  "group": "syntax",
  "severity": "fatal",
  "severity_note": "fatal, from the Flag column of the Peppol BIS Billing 3.0 UBL rules index retrieved 2026-10-18.",
  "spec": "Peppol BIS Billing 3.0, May 2026 release, EN 16931 model bound to UBL",
  "statement": "Supporting document description shall occur maximum once",
  "statement_lang": "en",
  "context": "cac:AdditionalDocumentReference",
  "test": "(count(cbc:DocumentDescription) <= 1)",
  "meaning": "The supporting document description shall occur at most once. The statement has no period and says shall. It is 56 characters. The statement says description. The flag is fatal. The context is cac:AdditionalDocumentReference. The published test counts cbc:DocumentDescription. The count comparison has a space before <= and a space after it.",
  "fix": "On a supporting document reference, send at most one document description.",
  "example_fail": "A supporting document reference has two document descriptions.",
  "example_pass": "A supporting document reference has one document description, or none.",
  "example_note": "Illustration of the condition in the official statement. Not an example published by the source.",
  "source_url": "https://docs.peppol.eu/poacc/billing/3.0/rules/ubl-tc434/UBL-SR-33/",
  "source_retrieved": "2026-10-18",
  "last_verified": "2026-10-18"
}