The interface dissolves.
The writing remains.
Your manuscript stays on your computer, not in a database in the cloud. The AI knows your project, reads your chapters, and holds your prose to your own standards — every session.
Your manuscript is a file,
not a database row.
Open it in any text editor. Back it up however you like. Keep writing even if Copperas disappeared tomorrow. Most AI writing tools keep your work in their cloud. Copperas keeps it on your machine.
AI that knows your project
without being reminded.
Every AI writing tool treats each session as a blank slate. You paste in your chapter. You re-explain your characters. You describe your voice. Copperas loads your characters, timeline, reference files, and prior session notes automatically — every time, without being asked.
Every word it writes is yours
to keep or discard.
Ask the Drafting Assistant to write a scene and it will — in your voice, against your style contract, consistent with your characters. Ask the Editing Assistant to read your chapter and it gives you findings to act on. Nothing reaches your manuscript until you click Apply. The control never leaves you.
Powered by a prose engine built
for long-form fiction.
The Longform Prose Engine is not a wrapper around a chatbot. It is a purpose-built compute infrastructure that maintains a persistent understanding of your project — characters, plot threads, chapter structure, style rules, continuity facts — and feeds that understanding into every interaction. It selects the right model for the task, assembles the right context, and applies the right editorial lens. Every AI feature in Copperas runs on it.
Writing a novel takes months. The tool you write in becomes the place where you spend those months — the room you think in. It should feel good to be there.
Copperas is designed to disappear. The interface is quiet. The typography is clean. Six handcrafted themes let you choose the light, warmth, and mood that suit the way you work. The editor shows your chapter with the surrounding scenes visible for context, and everything else stays out of the way until you need it.
There are no toolbars crowded with icons. No sidebars competing for your attention. No notifications. When you are writing, you see your prose and nothing else. When you need help, the AI Assistant is one keystroke away. When you are done, it closes and the words are all that remain.
This is intentional. Flow requires trust — trust that the tool will not interrupt you, that it will not lose your work, that it will be there when you come back tomorrow. Copperas earns that trust by being simple, fast, and honest about what it is doing.
The best writing sessions are the ones where time disappears. You sit down, you find the thread, and the next thing you know two hours have passed and the chapter is alive.
Copperas is built to protect those sessions. Voice input lets you talk through a scene without breaking eye contact with the page. The AI responds in conversation, not in forms and buttons. Timeline snapshots happen silently in the background so you never have to stop and save. When the editor finds something in your prose, it tells you in plain language and waits for your decision — it does not auto-correct or rewrite without asking.
Every design choice serves the same question: does this help the writer stay in the work?
Free to download.
Free to write.
The complete writing environment — editor, chapter navigation, version timeline, import, export — works without an account and costs nothing. AI features are the only paid tier. Try the environment first; add AI when you're ready.
For writers who choose not to use AI assistance: Copperas is for you as well, and it is free of charge. We respect your choice and your conviction, and we hope you find it a useful tool for writing your next novel.
Purpose-built for every
stage of the writing process.
Not a chat window bolted to a generic editor. Five AI roles, each with its own expertise and its own way of reading your work. A persistent understanding of your project that compounds with every session.
Characters, plot threads, chapter structure, your style contract. New projects start from one of 25 pre-built genre templates. Talk to it in plain language and the right specialist picks up the work.
Quick Read catches structure and continuity. Close Read marks prose patterns and missed opportunities. Deep Read gives full literary attention to every line, with findings at the sentence level.
Write a scene from scratch. Expand a passage. Tighten a chapter that isn't working. Every instruction runs through your style contract and reference files, so the prose lands in your voice. Nothing touches the manuscript until you click Apply.
Three independent AI readers, each with a different lens, responding without seeing each other's reactions. The same variation you would get from three actual humans reading your chapter cold.
A senior literary agent reads your book and gives you an honest professional evaluation. The Agent Assessment does not soften its findings. It reads the way an agent would — commercially, structurally, honestly.
Maps your novel's emotional and narrative momentum from opening to final page. Per-chapter pacing grades, an intensity score from 1 to 10, and the three to five most important momentum issues — ordered by impact.
Race, gender, sexuality, disability, religion, culture, age, class, and mental health. Cites specific passages with explanations and suggested alternatives. Select only the categories relevant to your manuscript — you don't need to run all nine.
Facts from every working session are harvested and fed back into future sessions automatically. The more you write with Copperas, the more precise every interaction becomes.
Free to write.
Pay only for AI.
The writing environment is free forever. AI features run on credits that map directly to actual AI cost — you always know what you are spending and why. No opaque limits, no surprise overages.
- Full writing environment
- Chapter navigator & editor
- Automatic version timeline
- DOCX import and export
- Six handcrafted themes
- Focus mode
- Everything in Local
- AI Assistant
- Quick Read + Close Read
- Drafting Assistant
- Beta Readers
- Agent Assessment
- Session memory
- Everything in Basic
- Deep Read
- 37% lower cost per credit
- Everything in Extended
- Maximum editorial depth
- 47% lower cost per credit
All prices in USD. Credits carry over when you top off ($5 for 2,000 credits, repeatable). Free trial includes 1,500 credits.
Download Copperas and start writing today.
Download freeApp interface available in English and Spanish · French and German coming soon