An invoice was received. Should it be paid?
The workflow
Seven rounds of questions, one subject at a time. Sums, dates, account numbers and statuses are computed in code rather than asked.
Four conditions end the review immediately: a fraud pattern, an invoice already paid, the wrong vendor or company, or a document that is not an invoice.
Three rule lists run side by side. Every rule that applies adds its actions: hold the invoice, dispute particular lines, or request a corrected copy.
A sequence of yes-or-no checks decides how the payment leaves: sent for approval, held for a signature, paid in the undisputed part, scheduled, or paid.
A handful of cases: for each model, one where it alone differs from the other two; one where all three miss the reference; one where all three agree. Each model's path is drawn on the chart in its own colour and line style. Where paths share a stretch, the lines run side by side. What no model reached is faded. Underlined questions open below with every model's answer and the state it read.