Introducing OpenWriter
OpenWriter is an open-source, markdown-native editor where your AI agent writes and you approve every word. Books, threads, newsletters and blog posts, published from one place.
Updated October 2026 to reflect OpenWriter 0.42.
Why OpenWriter Exists
Every writing tool makes you choose. Write here, publish there. Use this for social, that for email. And when AI helps, it sounds like every other chatbot instead of you.
OpenWriter is one editor that does all of it, built so your agent can work inside it.
What’s Inside
A real editor. Tiptap 3, markdown-native, light and dark mode, nine typefaces. Your documents are plain .md files on disk. No database, no lock-in.
Six compose views. Document, tweet and thread, X Article, blog, newsletter and manuscript. Each is shaped like where the words are going: character counts for tweets, metadata for blog posts, subject and preview text for email.
Books. Chapters, characters and worldbuilding live as separate docs. A manuscript binds them in order and compiles one book, and you can download it as EPUB for Kindle, or as Word, HTML or Markdown.
Writing that sounds like you. The Author’s Voice plugin learns from your own pages: what you avoid, how you punctuate, how long your sentences run. Select a passage, right-click, and Enhance, Shrink or Expand it in your voice.
Know which words are yours. Turn on Voice and every paragraph is tinted by who wrote it: you, your agent, or both. Version history shows who changed what.
Publish from the page. Post to X and LinkedIn, queue posts into recurring slots, and send your newsletter from your own domain. Blog posts go out as a Markdown commit to the repo behind your site.
Tools for your agent. The editor gives any MCP agent 61 tools for writing, searching, organizing, versioning and compiling books. Publishing adds 29 more. It works with Claude Code, Codex, OpenCode, Cursor, Windsurf and others.
The Agent Story
Your AI agent writes directly into the editor. Its changes appear as colored decorations: green for inserts, blue for rewrites, red for deletions. You step through them with the keyboard and accept or reject each one.
The agent does the work. You keep the final say.
Try It
The editor is open source under MIT and free.
Run npx openwriter setup to install it and connect your agent, or read the source on GitHub.