Octavo: Free forever (1 project, 3 research files, limited AI usage). Quarto: $20/month or $200/year (unlimited projects, 50 files per project, 10× more AI usage). Folio: $100/month or $1,000/year (unlimited research files, 5× more AI usage than Quarto, priority queue, early access to new models).
Key features
Remembers people and past context
Grammarly-class proofreading
Bring your own API key or run local model
Ghost text suggestions as you type
Two gestures to access all functions
Shows receipts for each reply
Memory stays on your Mac
Supports Anthropic, OpenAI, Google Gemini and Ollama
Custom actions with personalized shortcuts
Context-aware AI suggestions that read your chapters first
Source-grounded edits from PDFs, URLs, and YouTube transcripts
Red and green diffs requiring your approval
Export to Amazon KDP, Apple Books, Lulu, IngramSpark, Google Play Books, Draft2Digital
Chapter-aware AI agent
Citation engine with Chicago-formatted bibliography
Front matter and back matter editor
Version history to save and restore manuscript versions
Clean PDF and EPUB export with professional typography
What makes it different
Memory that crosses conversations and apps
Shows receipts explaining how each reply was generated
Minimal resource usage as small native macOS app
No account, analytics or tracking required
Keeps your entire book and research in context, unlike chat windows that start fresh each session
Returns edits as approvable diffs you control, not auto-inserted changes
Built specifically for book publishing with real front matter, back matter, and professional export formats
Cue
Chaptora