Prepare overdue VAT returns from a folder of invoices
Idea + starter prompt, not run by us yet
For: Freelancers and small firms behind on their periodic tax returns
A folder of invoices and receipts went to Claude Cowork, which prepared quarterly accounts from them. With the poster logged in to Elster, Germany's tax portal, the Claude Chrome extension then found the forms, filled them from those figures and filed the late Q3 2025 VAT returns. No programming was involved.
Steps
- Put your invoice and receipt PDFs in one folder, sorted by period.
- Ask Cowork to prepare a summary for each quarter and show you the totals and the documents behind them.
- Check the totals yourself or with your accountant before anything is filed.
- Log in to the tax portal yourself. Never share your sign-in or certificate with the agent.
- Let the browser extension fill the form, but press the final submit button yourself.
Starter prompt
Trial first: use [3] made-up invoices and [2] made-up receipts for one invented quarter, in a folder called [vat-trial]. Write the summary to [trial-summary]. Do not open the tax portal during the trial. In [folder] are my invoices and receipts for [period]. After my yes, prepare a summary for each quarter: net sales, VAT collected, VAT paid on expenses and the resulting amount due. List the documents behind each figure and flag any missing a date, a VAT number or an amount. Show me the summary and wait for me to check it. Later, with the tax portal open and logged in by me, fill in the VAT form from the approved figures and stop before the final submit. Stop and wait for my yes before each form is filled and again before submit. Showing me a filled form is not permission to file. Do not ask for my login, certificate or bank details.
Original post: X · @EastlondonDev · found via agentusecases.ai. Written up in our own words. We haven't run it, so test it on made-up data first.