The ceiling
What these seven limits have in common
Reread the "where it stops" column: each limit is the same one, seen from seven angles. A prompt acts once; a session lasts. Everything a prompt installs — precision, constraints, regime — degrades over the turns if no one maintains it, and degrades in silence: the fluency stays perfect while the substance leaves. The prompt is a point impulse. The session is a field.
The consequence fits in one sentence, and it is the whole diagnosis: an excellent prompt in a bad session yields an average result; an average prompt in a well-steered session can produce a real elevation. The lever is not in the phrasing. It is in the steering — the opening, the vigilance, the retake, the close.