Codex Writer
AI Writing Studio · v0.1.0
Craft your stories layer by layer — from a single line to a complete manuscript.
Codex Writer is a structured writing tool that takes a premise from synopsis to complete manuscript, one layer at a time. Write your opening idea, set your creative rules — genre, tone, POV, and custom guidelines — and expand downward through five stages, each generated from everything above it. Edit or regenerate freely at any layer; you have full control at every step.
Offline-first · BYOK · No account · PWA installable
OpenRouter · OpenAI · Anthropic · Google · Ollama · LM Studio
Layer architecture
“A young adventurer discovers a hidden world beneath the city…”
Quick start
$ Open Settings → Add API key
$ Create project → Write synopsis
$ Generate → Expand layer by layer
Features
No blank-page paralysis
One sentence expands into synopsis, plot, chapter outlines, and full prose. Each layer builds on the last with full context.
Discover your characters
Characters are extracted automatically from your story. Chat with them in-character to uncover voice, motivation, and backstory before writing a scene.
Lock in your creative direction
Set genre, subgenre, POV, tone, and custom writing rules. Every generation follows your guidelines — consistent voice across the full manuscript.
You stay in control
Pause at any layer to review, edit, or regenerate before the AI continues. Nothing is overwritten without your approval.
Bring your own AI
Works with OpenRouter, OpenAI, Anthropic, Google, Ollama, and LM Studio. Use cloud or local models — switch providers anytime.
Private by design
All data stays on your device. No accounts, no cloud sync. Works offline for reading, editing, and local AI generation.
Who it's for
Starting your first novel?
Break “write a novel” into five clear, manageable steps. Learn story structure as AI scaffolds your idea — then shape every layer to make it yours.
Great at prose, slow on plotting?
Let AI handle the outline so you can focus on what you do best. Test ideas, propagate changes, and keep long projects consistent without manual tracking.
The story is in your head — get it on the page.
One premise becomes a full draft. Your concept, AI execution, your approval at every step. Edit, regenerate, or reshape until it feels right.
How it works
01
Write synopsis
One sentence or a paragraph.
02
Generate summary
AI expands your idea.
03
Expand plot
Detailed story structure.
04
Break into chapters
Scene-by-scene outline.
05
Draft prose
Full manuscript text.
Privacy
Your stories stay on your device.
No cloud uploads. No analytics. No tracking. Data is stored in your browser's IndexedDB. Auto-backups and file export give you full control over your work.
storage: IndexedDB (local)
analytics: none
tracking: none
accounts: not required
cloud sync: none
api keys: stored locally, sent only to your chosen provider
Changelog
v0.1.02025-02-21latest- newLayer-by-layer expansion: idea → synopsis → summary → outline → prose
- newMulti-provider AI: OpenRouter, OpenAI, Anthropic, Google, Ollama, LM Studio
- newCharacter extraction and interactive character chat
- newStory Compass: genre, tone, theme, and style guidance
- newOffline-first with IndexedDB — all non-AI features work without internet
- newPWA installable on desktop and mobile
- newBYOK — bring your own API keys, no account required
- newAuto-backup and local file save/export
- newQuality checkpoints and manual intervention pauses
- newBuilt-in reader view for draft review
Download
Windows Installer
x64 · NSIS · 84.5 MB
v0.1.02025-02-21file: Codex Writer Setup 0.1.0.exe
requires: Windows 10 or later
type: Electron desktop app
Web App
PWA · No install required
access: runs in your browser
install: optional — installable as PWA
storage: IndexedDB (local, private)