Why dialogue goes flat, and how subtext fixes it
Flat dialogue has a signature: characters say exactly what they feel. "I'm angry with you." "I was lonely after you left." Real people rarely do that. They talk about the weather when they are angry and ask "have you eaten?" instead of saying they were lonely. The distance between what is said and what is meant is subtext, and subtext is what makes dialogue alive. This tool asks you for what each character is not saying, and then writes a conversation in which that thing is never said out loud.
The second signature of flat dialogue is that everyone sounds the same. If you cover the names and cannot tell who is speaking, the scene has failed. The elements that separate voices are simpler than they seem: sentence length, formality, whether a character asks or asserts, whether they respond to the other person or ignore them, and one or two words they overuse. Give each character a single line of personality and speech habit and the tool assigns those elements differently to each. "Blunt, few words" and "drunk but lucid, polite" is enough to split two voices cleanly.
Prose dialogue and script dialogue follow different rules. In prose, action beats and interior thought can sit between lines, so the lines themselves can be short and sparse. In a script there is no interior, so dialogue and action carry everything, and the lines need more rhythm and repetition. Start your input with "prose" or "script" and the tool writes accordingly: script mode returns only names and lines, prose mode returns quoted dialogue with brief action beats in between.
The scene is about twenty lines. That length is partly the free output limit and partly a craft choice, because conversations longer than that tend to sag. When you paste the result into your draft, add action around it: where each person is looking, what their hands are doing. Dialogue alone reads like a radio play.
The free tool runs three times a day without an account, and nothing you enter is used for training. If your cast is large and each character's voice has to stay consistent across chapters, write the speech rules into the Studio story bible; the AI reads them whenever it writes that character.