{
"invoice_number": "INV-2041",
"vendor": "Northwind Traders",
"issued_on": "2026-03-12",
"po_reference": "PO-8831",
"line_items": 4,
"total": 4820.0,
"source": { "page": 1, "bbox": [72, 118, 214, 136] }
}The core difficulty is reading messy documents, and the output is open-ended field values.