qbs784 Specifying acceptance
A criterion you cannot name one assertion for is not a criterion. It is a hope about the outcome, and it will be marked satisfied by whoever wants to be finished.
This skill owns the form a criterion has to take before work starts against it. It does not judge whether a check that already exists can fail.
Acceptance written after the fact describes what was built. Acceptance written before is the only version that can reject anything, which is why the form matters more here than anywhere else in the change.
Find the criteria before asking for them
A message saying the criteria are here almost always means they are in the repository — a requirements document, an issue, a design note — and the first move is to go and read them. Asking whoever sent you to paste what is already on disk spends their turn and reports an absence you never checked.
The same applies to the code the criteria describe. A criterion's nearest wrong reading is usually already resolved in the implementation, silently and in one direction; you cannot see which until you read it. Naming the ambiguity without checking what the code already chose is the weaker half of the finding.
If a listing comes back empty, that is a claim like any other: confirm it with a second command that would have matched something, and say where you looked before saying nothing is there.
The form
Three parts, and a criterion missing any one of them cannot be tested:
- the trigger — the condition under which the claim applies;
- the subject — what does the responding;
- the observable response — what an outside party can see happen.
"The exporter is reliable" has none of them. "When the upstream returns a 5xx, the exporter shall record the batch in the dead-letter table and exit non-zero" has all three, and the assertion that satisfies it is already visible in the sentence.
Observable means observable from outside the subject. A response phrased as an internal state — a flag set, a method called, a field populated — is satisfied by an implementation that sets the flag and does nothing else. Name the artifact, the exit code, the row, the emitted event, the file on disk.
Adjectives are not criteria
Fast, robust, reliable, secure, maintainable, performant, intuitive. Each of these is a category, not a claim, and a category cannot be red.
Every non-functional criterion needs three things stated with it: who measures, what number they read, and the threshold that fails. Without them the criterion is decorative, and it will be declared met by the person whose work it was supposed to constrain.
If the number cannot be produced yet, that is a finding worth recording — an honest "no measurement exists for this" is checkable, and an adjective is not.
Declaring a semantic is not evidence
Writing what something means — in a plan, a docstring, a decision record, a delivery report — establishes nothing about what it does. This is the most expensive failure in this skill's area, because the writing feels like the work.
The shape it takes: the same meaning is stated in three places, the implementation does something adjacent to it, and every check is green because no check distinguishes the two. It survives review because a reader comparing the code against the sentence finds them compatible.
So a declared semantic ships with two things, in the same round:
- A case that discriminates this meaning from the nearest wrong one. Not a case that exercises the behavior — one that comes out differently under the two readings. A behavior-level case that passes under both meanings has told you nothing, and it is the common outcome: the values chosen for it are usually the ones where the readings agree.
- A mutation proving that case is what holds the meaning. Break the implementation in the direction of the wrong reading and watch the case go red.
Missing the first is a claim with nothing behind it. Missing the second is
believing the case will fail rather than having seen it. Neither substitutes
for the other: the discriminating case does the work, and the mutation is the
proof it does. ledger:proving-the-regression owns the mutation half once a
check exists; this skill owns getting the discriminating case named before
anything is built.
Naming the nearest wrong meaning is the whole technique. "The timestamp recorded when the state was entered" and "the timestamp of the most recent sample" are compatible with the same sentence, the same tests, and different behavior. Write the second one down, then design the case that separates them.
Before the work starts
For each criterion, answer both:
- Which assertion satisfies this, and where would it live? No answer means the criterion is not yet one.
- What is the nearest meaning this could be read as instead? If nothing, say so — but the question is asked, not skipped, because the readings that cause damage are the ones nobody thought were available.
When you are about to accept it anyway
| The thought | What is actually true |
|---|---|
| "Everyone knows what 'handles errors gracefully' means here." | Everyone has a reading and they differ, which surfaces at acceptance when it is expensive. One assertion, or it is not a criterion. |
| "The test exercises this behavior, so it is covered." | Exercising is not discriminating. Ask which competing reading that test would come out differently under; if the answer is none, it covers neither. |
| "I wrote what it means in three places, so it is unambiguous." | Three statements of a meaning are one statement repeated. What makes it real is a case that fails when the code drifts to the neighbouring meaning. |
| "The measurement can be worked out during implementation." | The implementer will pick the measurement that their implementation passes. That is not dishonesty, it is the only measurement they can see from there. |
| "It is a non-functional requirement, so a number is not realistic." | Then the criterion is that no threshold exists, and it is not an acceptance criterion. Record it as an open question rather than as a bar the work will be judged against. |
Report
For each criterion: its three parts, the assertion that satisfies it and where it will live, and the nearest wrong reading you named. Where a criterion could not be brought to this form, say which one and what is missing — a criterion left as an adjective is a gate that will pass no matter what is built, and saying so is more useful than restating it.