Invoicing eats our Friday.

The plan

Prepare invoice rows for human verification. This is a manual, AI-assisted workflow: you copy approved inputs into Claude, check the output, and move the accepted result into your existing process. Start with the synthetic example below.

You need access to Claude and your team’s approved document or spreadsheet workspace. Use only data your business permits in those services. Tool plans and limits vary; this walkthrough does not require an API connection.

1. Prepare a small, useful input

Create a Google Sheet with supplier, invoice_number, issue_date, currency, subtotal, tax, total, due_date, source and status. Start with three synthetic invoices as text or PDFs. Keep one row per invoice and a link to the original in your private sheet.

Use this fictional sample for your first run:

INVOICE INV-104
Supplier: Example Studio
Issued: 2026-10-01
Currency: USD
Subtotal: 500.00
Tax: 40.00
Total: 540.00
Terms: due 2026-10-31

2. Give Claude a precise job

Open a new chat at claude.ai. Paste the prompt below, then paste the sample after it under a heading called INPUT. For a PDF, attach the sample file to the chat instead. Keep the source and instructions clearly separated.

Extract the listed invoice fields into a table. Copy explicit values only. Use UNKNOWN for missing or illegible fields. Do not infer currency from a dollar symbol, invent tax, change bank details, or decide whether to pay. Include the source text for each numeric value and flag duplicate supplier plus invoice_number pairs.

INPUT:
[Paste the sample or your approved source here.]

Read the response before continuing. If required columns are missing, ask: “Return the same result using every requested column. Mark unsupported fields UNKNOWN.” Do not fill gaps by asking the model to guess.

3. Check against the expected result

Example Studio | INV-104 | 2026-10-01 | USD | 500.00 | 40.00 | 540.00 | 2026-10-31. The amount is a draft extraction, not an approved payment.

4. Put the checked result to work

In the sheet use =ROUND(E2+F2-G2,2) to check subtotal plus tax minus total, assuming the columns above start at A. A zero flags arithmetic agreement only. Compare all fields with the original, check supplier and invoice number against accounting records, then enter the approved row manually. Handle payment separately.

Keep a status of draft, needs clarification, approved, or completed beside each item. A draft is not a completed action. If the service is unavailable, use the original source and your normal manual process.

5. Test the awkward cases

Test a duplicate invoice, an unreadable total, and an invoice with no currency. Hold each for review. Never let a zero arithmetic difference override a wrong supplier, altered bank instruction, or duplicate invoice. Measure corrections per invoice.

Run the same cases again after changing the prompt or source. Keep the input, output, correction, and reviewer decision together. Expand only when someone can reliably check the results.

If the result is off

Narrow the input to one record and recheck the source. For missing facts, ask the process owner. For an unsupported statement, remove it and add an explicit constraint to the prompt. If the same failure repeats, do the task manually until the source or instructions are fixed.

Scope: This is an original illustrative recipe with synthetic data, adapted from the field guides below. It is not a live-tested integration or a claim of time saved. Claude’s file-upload documentation explains supported attachments; the copy-and-paste path does not need file uploads.