The seller net-sheet (no-code rung)

The purest no-code app: fixed inputs (price, loan payoff, commission %, closing costs), fixed math, one number out. This is the 'Artifact for speed' case. No flexibility needed because the formula never changes, so describe it in chat and let Claude build a runnable Artifact, or a single-file tool in Claude Code with a tiny form. The logic is the whole app. (B12 already named the net sheet as your model first endpoint, this is that math, made real.)