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Recipe: find overdue invoices and draft payment reminders

Give Hermes the list of your unpaid invoices. It tells you which ones are overdue on a given day, how much is overdue in total, and writes one polite reminder per customer, in European Portuguese, saved in a file.
Time needed 5 minutes
You need A Hermes agent connected to an AI model and a CSV export of your open invoices (customer, invoice number, amount, due date)
Result A table of overdue invoices with the days late, the total, and a file with one email per customer

Hermes writes the emails, it does not send them

In this recipe Hermes only drafts the reminders. You read them, then send them from your own email. Check that each invoice is really still unpaid first: a payment that arrived this morning is not in your export.

1. Export and upload your open invoices

Export the list of unpaid invoices from your invoicing or accounting software as a CSV file. Then, in the dashboard, open FILES → workspace and click UPLOAD (see Hermes reads a contract for you).

This is the test file we used, open-invoices.csv. The dates are day/month/year, as in most Portuguese software:

customer,invoice_no,amount_eur,due_date
Cafe Central,FT 2026/101,245.50,20/10/2026
Hotel Mar Azul,FT 2026/104,1320.00,31/10/2026
Restaurante O Pescador,FT 2026/107,418.75,05/11/2026
Cafe Central,FT 2026/109,189.90,08/11/2026
Pastelaria Doce Lar,FT 2026/111,76.40,15/11/2026
Hotel Mar Azul,FT 2026/112,960.00,12/11/2026
Mercearia da Praca,FT 2026/115,58.20,22/11/2026
Restaurante O Pescador,FT 2026/116,302.10,30/11/2026
Escola Primaria do Norte,FT 2026/098,640.00,30/09/2026
Pastelaria Doce Lar,FT 2026/117,112.35,14/11/2026

2. Ask for the overdue list and the reminders

Two details make the answer reliable: give today's date, and say how the dates are written (day/month/year), so that 05/11 is read as 5 November, not 11 May. In CHAT we wrote:

Today is 15 November 2026. Open workspace/open-invoices.csv (my unpaid invoices; dates are day/month/year). List the invoices that are overdue today, with the days late, and the total overdue. Then write one short, polite payment reminder per customer in European Portuguese (one email per customer, with all their overdue invoices) and save them in workspace/payment-reminders.md.

Hermes lists the overdue invoices

  1. The overdue invoices, oldest first, with the number of days late.
  2. The total overdue: 3,886.50 EUR.
  3. Hermes explains what it left out: one invoice is due today, so it is not overdue yet; two more fall due later in November.
  4. It wrote five emails, one per customer, in the file payment-reminders.md.

3. Read the reminders

Open FILES → workspace and download payment-reminders.md (the download arrow on its line), or ask Hermes in the chat: "Show me the reminder for Hotel Mar Azul." This is one of the five emails from our test, exactly as Hermes wrote it:

## Hotel Mar Azul

Assunto: Lembrete de pagamento – faturas FT 2026/104 e FT 2026/112

Boa tarde,

Verificámos que as faturas abaixo se encontram por regularizar:

- FT 2026/104 — 1 320,00 € — vencida em 31/10/2026 (15 dias de atraso)
- FT 2026/112 — 960,00 € — vencida em 12/11/2026 (3 dias de atraso)

Total em atraso: 2 280,00 €

Agradecemos que proceda ao pagamento assim que possível. Se já o efetuou, por favor ignore esta mensagem e envie-nos o comprovativo.

Com os melhores cumprimentos,
Sunrise Bakery

The emails use Portuguese number formats (1 320,00 €) and add the accents our file did not have (Café Central, Escola Primária). Customers with two late invoices get one email with both and a total.

Check that it worked

We worked out the answer ourselves before asking Hermes. Everything matched:

  • 7 overdue invoices from 5 customers, with the right number of days late (from 1 to 46 days).
  • Total overdue 3,886.50 EUR. Per customer: Hotel Mar Azul 2,280.00, Escola Primária do Norte 640.00, Café Central 435.40, Restaurante O Pescador 418.75, Pastelaria Doce Lar 112.35.
  • The invoice due on 15 November was correctly left out.

To check yours, sort the CSV by due date in your spreadsheet and add up the amounts before today. The total should be the same.

Make it yours

  • Give Hermes your business name and how you sign emails. In our test it signed Sunrise Bakery because the name was already mentioned earlier in the same chat.
  • Be gentler with recent invoices: "Only write reminders for invoices more than 7 days late."
  • Change the tone for very late invoices: "For invoices more than 30 days late, write a firmer email and ask for a payment date."
  • Run it every Monday and get the list on Telegram, see Schedule a recurring task. Upload the new export first.

Common problems

The days late are wrong

Hermes probably read the dates the wrong way (month/day instead of day/month). Say how the dates are written, as in step 2, and ask again.

An invoice is missing from the list

Check that it is in the CSV, and that its due date is before the date you gave. An invoice due today is not overdue. If you want it included, say so: "Include invoices due today."

Is it OK to upload customer data?

The file stays on your agent's server. To answer, Hermes sends the parts it needs to your AI provider, as for any question. Upload only what you need (name, invoice number, amount, date), not addresses or tax numbers.

Next steps