Every step in an operational process is one of two things. Either a competent new hire could do it correctly from the written procedure alone, or they would have to ask someone. The first is a rule. The second is judgment. The distinction decides what an automation should be made of, and getting it wrong is the most common way to turn a cheap improvement into an expensive one.
Rules are the majority
Checking that a form has every required field. Matching a payment to an invoice. Moving a record from one system to another. Flagging a date that has passed. These are lookups and comparisons, and they have been automated reliably for forty years. A rule costs nothing to run, finishes in milliseconds, gives the same answer every time, and can be audited by reading it.
Judgment is rarer than it looks
Deciding what kind of document has arrived. Reading a scanned form that was filled in by hand. Proposing which field in one system corresponds to which field in another. These need something that can cope with variation, and this is where current AI models earn their place. It is close to the only place they earn it in operations.
The expensive mistake
Put a model where a rule belonged and the result is slower, costs money every time it runs, gives slightly different answers on different days, and cannot be audited without being re-run. It also fails in ways a rule never does. A reconciliation that is right most of the time is not a reconciliation.
The mistake is common for two reasons. Procedures are often not written down, so steps that are in fact rules look like judgment because only one person knows them. Writing the procedure down usually dissolves the judgment. And the tool is often chosen before the work is understood, so the work gets shaped to fit the tool.
A practical test
When a step seems to need judgment, ask the person who does it today how they decide. If they can give you the decision in a sentence or a short list, it is a rule. If the answer begins with "it depends" and does not end, it may be judgment. Even then, a model should propose and a rule should check before anything in a record changes.
Applied honestly, the test leaves most operational processes as rules with one or two judgment steps at the edges. That is a far cheaper thing to build, and a far easier thing to trust.