{
  "document_url": "https://example.com/unknown-document.pdf",
  "categories": [
    {
      "name": "Invoice",
      "description": "A financial invoice from a vendor"
    },
    {
      "name": "Receipt",
      "description": "A payment receipt"
    },
    {
      "name": "Contract",
      "description": "A legal agreement between parties"
    },
    {
      "name": "Other",
      "description": "Any other document type"
    }
  ]
}