Asten, a writing desk for novelists that catches continuity errors

Alpha 0.1.0-alpha.1 · published 29 October 2026. Windows and Linux desktop app. macOS and ARM builds are planned.

Asten is built to keep a record of the facts you confirm about your story and to mark any sentence that contradicts one. It never writes prose.

Last reviewed 10 November 2026

What works today and what is not there yet

A manuscript editor with a binder, comments, find, page view and tracked changes.
A canon engine with rules that compare each sentence with the facts you confirm.
Cast, timeline and world-board views, and a history with snapshots, drafts and merge.
Export to Markdown, plain text, Fountain, HTML, DOCX, EPUB 3 and Final Draft, and import of all but EPUB.
An optional assistant that explains marks and proposes facts for you to confirm. It shows the exact request before sending it.
The manuscript stays in one file on your computer unless you switch the assistant on and ask it something.

Checks against the live AI services. The assistant is tested against mock servers.
Signed installers, and builds for macOS, Windows ARM64 and Linux aarch64.
Phone versions, which wait for device testing.
Stable file formats. They may change before 1.0.

Chapter 3 says auburn hair. Chapter 19 says black.: Built to mark the sentence that contradicts a fact you confirmed.
A character acts after the scene where they died.: Designed to flag the sentence against the settled death. A note that says flashback clears it.
Story order and reading order drift apart.: Built to track story time and reading order, and flag time running backwards.

For your engineers

Seventeen rules in seven families. Every mark shows its rule, its sentence and the fact behind it.
A project is one .asten file, a SQLite database you can move to another computer.
The assistant runs local inference, or uses your own provider key or an installed agent CLI.
It does not judge prose quality or find every plot hole. Word and Google Docs pair with the desktop app as guests.
The builds are not code-signed. The portable zip does not install the WebView2 runtime if it is missing.

Ask for a demo on the sample novel. Nothing of yours needs to leave your computer.