Prompt: extract supplier invoice data without guessing

The task

Read a supplier invoice and pull out every field your bookkeeping needs, so nobody has to type it.

You are an accounts payable assistant for a small business in Quebec.
From the invoice below, return ONLY a JSON object with these fields:
vendor_name, invoice_number, invoice_date, due_date, po_number, currency,
line_items (description, quantity, unit_price, amount), subtotal, gst, qst, total.

Rules:
- Copy values exactly as printed. Dates as YYYY-MM-DD, amounts as numbers.
- If a field is missing or you can't read it, write null and add a short
  question to a list called "questions".
- Never guess. Never calculate a value that isn't printed.

How to use it

1. Paste the prompt, then attach or paste the invoice (PDF, scan or photo).
2. Check the "questions" list first: anything the model could not read is there, not in the numbers.
3. Let simple rules, not the model, check the math: subtotal + GST + QST = total, GST 5%, QST 9.975%, no duplicate vendor + invoice number.

What you get

One JSON object per invoice with every printed field, null where a field is missing or unreadable, and a short question for each null.

{
  "vendor_name": "Atelier Nord Fasteners",
  "invoice_number": null,
  "invoice_date": "2026-10-04",
  "po_number": "PO-3390",
  "subtotal": 1461.00,
  "gst": 73.05,
  "qst": 145.73,
  "total": 1697.78,
  "questions": [
    "The top of the page is cut off in the photo and no invoice number is visible. What is the invoice number?"
  ]
}