Writing
Writing a good chapter prompt
The highest-leverage thing you can learn here.
Output quality tracks your prompt more than your model choice. The good news is that the skill is small and learnable in an afternoon.
Say what happens, not how to write it
The style is already handled — that is what the register you picked at creation is for. Spend your prompt on events: who is in the scene, what they want, what changes by the end.
Weak: “Write an exciting, immersive chapter with great dialogue.”
Strong: “Mara confronts Joren at the water gate about the ledger. He admits he sold the manifest but not to whom. She leaves angrier than she arrived, and the reader learns the seal is a forgery.”
End with the change
A chapter that ends where it started is the most common failure. Naming the shift — someone learns something, loses something, decides something — fixes it in one clause.
Vague is genuinely fine
“Continue from the cliffhanger” works, because the model has your previous chapters and will search them for anything it is unsure about. Detail helps when you have a specific outcome in mind; it is not required.
Save the fine control for revision
Do not front-load every constraint. Get a draft, then revise: “too much interiority in the middle third, cut it and give the argument more room”. Revising is cheap, because the whole history is already cached — you are only paying for the new instruction and the new chapter.
Set the length once
Novel settings has a target words per chapter. Setting it there keeps it out of every prompt and keeps the system prompt stable, which is better for both consistency and cost.