Where the human belongs
A person earns their place in the loop at four kinds of moment, not everywhere, but not nowhere.
The goal is not to supervise the machine. It is to keep judgement at the specific points where a rule would be guessing, and let the system run freely everywhere else.
Hard to reverse
The action has real consequences if it is wrong
Refunds, contract changes, anything that touches money or a commitment. When undoing the action costs more than pausing for a person, the pause is worth it. Automate the preparation; keep the approval human.
Genuinely ambiguous
The input does not map cleanly to a rule
A reply that could be an objection or a scheduling note, a record that fits two categories, a case the rules did not anticipate. A machine forced to choose will choose confidently and often wrongly. A person reads the ambiguity a rule cannot.
Outside the rules
It is an exception, not the standard case
The system should recognise what it was not built for and route it to a review queue rather than forcing it down the happy path. The exception handled by a person today is the pattern that informs a better rule tomorrow.
Relationship-sensitive
A customer would notice a machine
A moment where the wrong automated touch reads as careless, a sensitive account, a complaint, a high-stakes negotiation. The system can prepare the response; a person decides whether and how to send it.
The rule that runs the seam
Act on strong evidence; surface everything else, and drop nothing.
Knowing the four moments tells you where a human belongs. This is the rule that puts them there automatically: the system acts on its own only when the evidence is strong, and routes everything short of that to the person, rather than guessing or discarding it.
Auto-act only on strong evidence. Require two independent signals before the system does anything hard to undo. One clue can be wrong; two rarely agree by accident. Precision governs the automatic path.
Surface the uncertain, never drop it. The cases that fail the strong-evidence bar are not thrown away, they go to the review lane. The doubtful case stays visible instead of being lowered past the bar for acting on it.
Let the system say "I am not sure". A machine that routes an ambiguous case to a person is working correctly; one that picks a confident default is the failure in the opening. An honest "I do not know" beats a confident wrong answer.
Search widely, act narrowly. Cast a wide net assembling candidates and context, that is cheap, and be strict about what the system executes without a human, because a wrong action there is expensive.
The design principle
Place the human at the decision, not at the data entry, where their judgement changes the outcome.
A person retyping fields between two systems is not "in the loop" in any useful sense. That is exactly the handling a machine should take. The loop is worth a human only where their judgement changes what happens next. Design the seam so the system prepares the decision and the person makes it, rather than the other way round.
