Main idea

The instructions you give an agent at the start are generic: aggregate, split by topic, keep a history. They hold for any subject at all, and that is what makes them easy to write.

The instructions that make the difference afterwards look nothing like those. Two contractors working for a building share the same surname: the directive says to use the meaning of the email to settle which one is being referred to. A co-owner is named sometimes under her maiden name, sometimes under her married name: without an instruction, the agent opens two records for the same person. A debtor who owes eighty euros isn't tracked like one who owes six thousand: the directive puts the threshold at a hundred. None of these rules can be deduced from the emails themselves — each comes from someone who knows the building.

That is precisely what gives them their value. A generic instruction reproduces what the agent already knew how to do; a ground directive hands it knowledge that existed only inside one head, and that it then applies to every email, without forgetting and without tiring. The useful work is therefore not to phrase the request better, it is to spot the tacit rules you were applying without ever having written them down.

Why it matters

This shifts what you think you have to learn in order to work with an agent. The skill isn't in drafting the instruction, it is in taking inventory of what you know and the text doesn't say — an inventory nobody can take for you, and that only comes to light when you notice a processing error.

It also gives a criterion for judging a context's maturity: the volume of its specific directives, not the quality of its original instruction.

Nuances and limits

A ground directive expires silently. The hundred-euro threshold was set in a given situation; it goes on applying long after that situation has changed, and nothing in the processing signals the gap.

And this knowledge isn't always right. Writing down a tacit rule makes it systematic, including when it was a shortcut you would have departed from by hand in front of a particular case.

Open questions

• How do you spot a tacit rule before a processing error reveals it?