The ledger asks the model to show its work before it counts the money

This is a submission for Weekend Challenge: Generosity Edition What I Built A donation ledger for a group too small to buy software. It is a Google Sheet, some Apps Script, and one public page a donor can open. The group I had in mind is the kind that exists on every street: a neighbourhood fund, a school parents' group, a committee that collects for winter coats. Money arrives over WhatsApp and leaves in cash, and somebody keeps it in a notebook. The arithmetic is not the hard part. The hard part arrives three months later when a donor asks where their money went, and answering needs the notebook, the person holding it, and an afternoon. Software for this exists and is priced for organisations with a finance team. So the ledger stays in a spreadsheet a volunteer already knows how to open, and the only thing added is what a spreadsheet cannot do alone: read messy human messages, refuse to trust its own reading , and publish the page that answers the question before it is asked. Demo The public page a donor opens → That page is the deployed page, byte for byte, with one line changed: where the Apps Script version writes <?= data ?> , the demo fetches the same JSON from a file so you can read it without a Google account. The JSON is produced by running the sample month through the same recordEntry() and publicView() the real script uses, so if the ledger rules change, the demo changes with them or the build fails. The sample month deliberately includes the things that go wrong: a receipt two volunteers forwarded, a donation typed with one zero too many and later corrected, and a reading the checks refused to trust. What the model read, and whether it was allowed to count → The ledger page shows the result. This one shows the part worth showing. Pick any of six real donation messages and it highlights the exact characters Gemini says it read the amount from, lists the three checks with their outcomes, and says why the row was posted or held. It is fed by a recorded run