The books notice what is unusual
Rules, not models, read the live books every day and raise an alert with its evidence — a near-duplicate bill, an odd manual journal, a cashier's voids, a vendor's price drift, a bad GSTIN, an uncharged room, an unmatched bank line. Nothing posts by itself.
The rule underneath the whole of the books is that nothing posts without a person. So this is detection, not action: every rule reads the books that are already live and raises a row with its evidence, and a person decides.
The rules
Two live vendor bills from the same vendor for the same amount within thirty days under different numbers. A hand-posted journal that is a large round number, or posted in the small hours, or far above the entity's usual. A cashier whose voids or discounts in a day are above the house's threshold. A purchase line more than a fifth above the average of the last five for the same item and vendor. A vendor's or a company's GST number that fails its format or its checksum. A room occupied on a past day with no room charge posted that day. A bank statement line unmatched for over a week. A vendor, a chart account or a bank account edited — the books notice when the data behind the money moves.
A rule that fires again on the same thing refreshes the row; an alert whose rule stops firing is resolved by the scan as no longer seen.
Assistance that is read-only
Vendors that bill most months and have not this month — what to accrue before the close. When a vendor bill is entered, the accounts that vendor's last five bills used are offered first.
Why rules first
A model needs a year of a hotel's own history to be worth trusting, and it needs the rules to have been right before it. The rules are here now and stay; the model is built when the history exists.