Paste a public GitHub repository, or connect GitHub for private ones, and Subcanvas draws a box for each main folder, with that folder's README inside. Double-click any box or arrow to open the whiteboard or page inside it, as deep as you need. Add a .subcanvas file to say what connects to what, put a public diagram in your README, or let an AI agent like Claude Code edit it with you. It works for class notes and plans too. Open source, and free for one person; Pro is $5 per editor a month.
