The script supervisor for prose
A continuity checker for novels and book series
Film sets have staffed a continuity supervisor for a century, because a story at scale cannot live in one head. Novels have the same problem. Bunsho is the first tool built to solve it the same way.
What continuity errors actually look like
They are almost never dramatic. They are the small facts that drift while you are busy writing the story: the mistakes readers catch on their first pass because you have read the page forty times and see what you meant, not what is there.
Character drift
Arvind is twenty-seven in chapter 3, and twenty-two in the same winter, nine chapters later.
Knowledge leak
Mira references the letter on page 5. She doesn’t learn it exists until page 8.
World rule break
Teleportation requires a metal artifact, except in scene 34, where nobody is carrying one.
What a finding looks like
Bunsho remembers who knows what, who is where, what is broken, and what an object means, and it ties each of those to the exact sentence that established it. So a finding is never “this feels off.” It is: “Mira references the letter on page 5; she doesn’t learn of it until page 8. Here are both sentences.”
Checking is a deliberate act, not an ambient process. Three honest buttons: Check this chapter before you move on. Review changes to re-check only what you have touched since the last pass. Full review for the whole manuscript. Your typing is never watched and never metered. The script supervisor reads when you ask.
Your manuscript is local-first: it lives on your device, not in our database. When you run a check, only the pages being checked are sent for analysis, and they are never used to train models.
Why a bigger context window doesn’t fix this
Most AI writing tools re-read your manuscript and improvise, and they forget: eye colors change, the dead walk, characters know things they were never told, and the tool cannot say why it believes anything. Bunsho only flags what it can show you, so every finding is checkable, citable, and worth trusting.
Continuity errors that break cause and effect have a common name: plot holes. And the same memory that catches errors after the fact also keeps Director Mode, so drafted scenes can’t introduce new ones.
Common questions
What is a continuity checker for fiction?
A continuity checker reads a manuscript and flags places where the story contradicts itself: a character whose age drifts between chapters, an object that appears somewhere it was never taken, a scene where someone acts on information they were never given. Film productions staff this role on every set. Bunsho does the same job for prose.
Do I have to fill in a story bible first?
No. The World tab fills itself from your manuscript: characters, places, objects, relationships, and world rules appear as you write, each tied to the sentence that established it. It works both ways. Add a character before she has a scene, correct an eye colour, or pin a rule of your world by hand, and Bunsho treats what you wrote there as canon and checks your chapters against it.
Does it check while I type?
No. Checking is deliberate. You run a check when you want one: a single chapter, everything that changed since your last review, or the full manuscript. Your writing itself is never metered and never interrupted.
Does it work for a whole book series?
Today Bunsho checks continuity within a manuscript. Cross-book series canon, keeping one story straight across a whole series, is the headline of our roadmap, because series writers feel this pain most.
Write fearlessly. Check before you move on.
Bunsho is free to download. Put a script supervisor on your manuscript today.