The synopsis or description field is the single biggest lever you have over what gets generated. Everything else on the create screen narrows the space; this is where you say what the book actually is.

Most disappointing first drafts trace back to a description of about fifteen words.

What a weak description looks like

A fantasy story about a young hero on a quest.

There is nothing here to work with, so what comes back is the average of every fantasy story ever written: a farm boy, a prophecy, a mentor who dies, a dark lord. The output is generic because the input was.

What a strong one looks like

Mira draws maps for the city guard. She has just realized the maps rewrite the land they depict, and someone has commissioned a map of her own district. She has eleven days before it is delivered. She cannot tell anyone, because the only people who would believe her are the ones who commissioned it.

Same length. Completely different result, because it contains a person, a situation, a clock and a reason she cannot take the obvious way out.

The four things worth including

A specific person with a specific problem. Not "a young woman" but what she does and what has just gone wrong for her.

Something that has already happened. Stories start after something changed. Say what changed.

What is in the way, and why it cannot simply be removed. This is the single most useful sentence you can write, and it is the one people leave out.

Tone. A sentence naming the feel: darkly funny, warm and low-stakes, tense and procedural. Otherwise you get the neutral default.

Optional but useful: an ending or a direction if you have one, and anything you specifically do not want.

Things that make output worse

• Listing genre conventions. The genre and sub-genre fields already do that. Repeating them in the description just tells the model to be more typical.
• Summarizing the whole plot beat by beat. That belongs in the outline, not here. A description crammed with events produces a rushed draft.
• Vague quality words. "Epic," "gripping," "unforgettable" describe how you want readers to feel, not what happens. They carry no information.
• Contradictions. "Lighthearted and brutal" gives conflicting instructions and produces neither.

Match the length to the format

• Short stories need one clear situation. Two or three sentences is plenty, and more can crowd out the ending.
• Novels benefit from more: the lead, the situation, the obstacle, the tone, and roughly where it is going.
• Children's books need the character, the problem and the feeling. Keep it simple, because the book is simple.
• Comics and webtoons should include what the world looks like, since the description is also steering the art.
• Non-fiction needs the promise instead of a plot: who the reader is and what they can do afterwards. See How to write a non-fiction book with AI.

Iterate before you spend

You do not have to get it right first time, but rewriting the description is free and regenerating a book is not.

A useful loop: write the description, generate an outline, and read it. If the outline is generic, the description was, and no amount of regenerating will fix that. Go back and add the missing specific, then try again. Outlines are cheap compared to full generations.

If the draft is not what you wanted

Nine times out of ten the fix is in the description rather than in the model.

• Draft feels generic? Add a specific detail only your version of this story has.
• Wrong tone? Name the tone explicitly. Never assume it is implied.
• Characters all sound the same? The description named one person. Name two, with different wants.
• Too rushed? The description contained too many events. Cut it back to the opening situation.
• Went somewhere you did not want? Say what you do not want, directly.

Where the description goes afterwards

It is not throwaway. Your synopsis carries into your story's library page, feeds recommendations, and is used when generating store copy such as the blurb and keywords in the Publishing Kit.

Worth knowing: a description that works well for generation is not the same thing as a blurb. Generation wants clarity and specifics including the ending; a blurb wants a hook and withholds the ending. Write the first here, and write the second later. See How to write a book blurb.

Stuck for a premise? The free book idea generator produces starting points, and 50 book ideas by genre has fifty written to be used exactly this way.