Run each significant exchange against this list before deciding it stays as written. Each item derives from a test in §7 or a pattern in §8. The engine I can state, in one sentence each, what both speakers want from the other in this exchange. Both wants are directed at the other person, and both are immediate rather than story-scale. The balance of information, power or feeling is different at the end than at the start — or has been contested and held. Removing the exchange would cost the reader something the summary line cannot carry. Domains I can name which domains — plot, character, relational, theme, texture, silence — this exchange actually serves, rather than merely touches. The relational domain is doing something; status is not simply fixed by default. Any information delivered here comes at a cost to the speaker, not a courtesy to the reader. No character says something purely so that the reader can learn it. The two channels Text and subtext are not identical for at least the key turns. I can name which mechanism from §6.4 each oblique turn is using. The exchange has some cooperative turns, so that the flouting ones register. I have not spent the gap-closing move here unless this is the place for it. Silence At least one speaker is withholding, deflecting or declining to answer something. I know who else is in the room, and whether their silence is doing work or is an oversight. I know who is being discussed and is not present. Voice With the tags stripped and the lines read aloud, I can tell who is speaking without relying on content. I could not move this exchange’s best lines into another character’s mouth without loss. Each principal has a different average turn length, a different relation to questions, and a different default evasion. Surface Every attribution that is not said or asked is justified; no adverb is compensating for a line that has not been written. Action beats between turns carry a second function, and are not tags with extra words. Names are used in the vocative only where the vocative is doing something. Dialect is carried by syntax, idiom and lexicon rather than by spelling — or, where it is not, I can defend the choice on the grounds set out at §8.9. Shape The exchange begins at the first turn that could not be cut and ends at the last. Interruptions cluster at the crisis rather than being distributed evenly. The turns cannot be reshuffled without loss.