Spine
The invisible structure that holds the argument upright.
An editorial platform for sustained writing, with AI as thinking partner.
The assumes chain
Track which concepts each chapter depends on. If your methodology assumes something you haven't introduced, Spine shows the break.
Living editorial conversation
Text-anchored annotations, threaded discussions, and edit proposals. The editorial process happens alongside writing, not weeks later.
AI editorial partnership
Connect Claude to your manuscript via MCP. 62 tools for reading, annotating, proposing edits, and reviewing -- not summarizing, but thinking with you.