A beginner who gets four notes on a first draft fixes none of them. We knew that from teaching before we knew it from data, so the Coach prompt has carried a one-idea rule for white and yellow belts since the first version: one weakness, one suggestion, one rewrite prompt. It was labelled a hard requirement. It was restated as a schema. And when we measured it, the model was returning four suggestions to a white belt in eight of eight beginner critiques, with the judge scoring those replies three to six out of ten.
The model was not failing to notice the rule and it was not failing to read the lyric. It was filling the fields it was given. A response format with an array called suggestions gets suggestions, plural, however firmly the paragraph above it says otherwise. That is worth knowing about every AI writing tool you use: the shape of the output wins over the instructions about the output.
So we stopped asking. Beginner replies are now collapsed after the model answers and before you see them: the arrays are cut to one item, deterministically, whatever the model intended. Belt calibration in the harness went from 65 percent in the first baseline to 93 percent in the last one. The judge's note on the best white-belt critique in that run was that it "stays on a single plain priority with a concrete rewrite," and its only complaint was that the reply did not also mention the clichés. Correct. One idea is the point.
Why one? Because a first draft has a dozen things wrong with it and exactly one of them is the thing to learn this week. A white belt who is told the imagery is abstract, the rhymes are sing-song, the chorus arrives late and the bridge restates the verse has been told the truth and has learned nothing. The same writer told only that "I feel so empty when you walked past" should be a moment they can see, with a rewrite prompt that says pick one thing you were holding, will write a better line tonight. Next week, the rhymes.
It is also why the daily session prescribes rather than offers. The session engine picks the one skill your recent graded attempts are weakest in and gives you that drill, then a writing step that uses it. The library of drills is there if you want to browse, but the plan exists so you do not have to, in the same way the one note exists so you do not have to triage your own draft on day one.
The drill on this page is the beginner's daily one: object writing, five minutes, one object, every sense. It has one instruction and no grade, and it is the exercise Coach's one note most often turns out to be pointing at.
