If Two People Cannot Apply It, It Is Not a Rule
Last timeThe Price of Saying No
A safety intention becomes a rule when two readers can apply it to the same request and agree. Here is the rewrite that gets you there, and what the rest of the document is doing.
Seven lessons have been about mechanism: where a rule can live, what each
placement holds against, and what it costs to check and to refuse. None of them
asked what the rules should say. That gets answered in a document nobody reads
twice, and the document has one failure mode worth naming, because it is nearly
universal and invisible from the inside.
Somebody writes "do not help with anything harmful." Everyone in the review
nods, because everyone agrees with it, and it goes into the policy. An engineer
then has to build something and discovers the sentence does not say what to
build, so they make a series of small decisions alone: which categories to
filter, where the threshold goes, what the refusal says. Those decisions are
the actual policy. The document describes something else.
The test is agreement, not approval
There is one test for a written rule, and it is cheap. Take twenty requests
from your own traffic, chosen because they are near the line rather than because
they are obvious. Give them, with the sentence, to two people who were not in
the room when it was written. Ask each independently to label every request as
allowed or refused under that sentence. Then compare.
If they agree on nineteen or twenty, you have a rule. If they agree on fourteen,
you have a topic. The sentence feels like a rule to its author because the
author has a specific set of cases in mind, and those cases are not in the
sentence. Two readers supply their own, and theirs differ.
| Two readers agree, per c | Cases in the test set | Times it fired last mont | Exceptions logged | |
|---|---|---|---|---|
| Do not help with anythin | 41 | 0 | 0 | 0 |
| No dosage information fo | 94 | 120 | 310 | 4 |
| Be helpful but safe | 23 | 0 | 0 | 0 |
| Refuse working exploit c | 88 | 85 | 47 | 11 |
| Never send email to an a | 100 | 30 | 6 | 2 |
The pattern in that table is the whole lesson. Agreement rises exactly as the
sentence gets narrower and more boring. The email rule scores perfectly because
it mentions no values at all: it names a comparison between two strings, and
two readers cannot differ on it. The two sentences everyone liked best score
worst.
The lesson stops here
6 more paragraphs to go
You have read the opening. The rest of the argument, the problems that check whether it landed, and the lines worth keeping at the end all come with a plan.
The first lesson of every course in the library reads the whole way through, free, so you can see exactly what the rest of them are.
See the planThe contentsThis is the reading half
Starting the course gives you your own copy of it. Every idea on every page has problems standing under it, marked with a reason rather than a tick, and any sentence you do not believe can be opened and argued with. None of that can happen on a page nobody owns.
The contents