Project Canvas

A .canvas file is a board: an infinite canvas whose cards can be sticky notes, text, images, frames, or live editors mounted on real workspace files and shared documents. A mockup card renders the mockup. A spreadsheet card renders the grid. A mindmap card renders the mindmap.

The editor is built into Nimbalyst, so any workspace can open a .canvas file you write. Write the JSON directly with the Write tool; there is no MCP tool for boards.

When to use a canvas

• Laying out several existing files spatially, screens of a flow, docs in a workstream, a review board
• A workspace or project overview that mixes documents, mockups, data, and notes
• Anything where the point is the arrangement of real artifacts, not a drawing

Use Excalidraw for freeform drawings and architecture sketches. Use MockupLM for a single UI screen. A canvas is the thing that holds several of those at once.

File format

JSON Canvas 1.0 superset. Every spec field keeps its spec meaning, Nimbalyst data lives under x-nimbalyst, and unknown keys at any level are preserved verbatim so a board written by another tool survives a round-trip.

{
  "nodes": [],
  "edges": [],
  "x-nimbalyst": {
    "version": 1,
    "meta": {
      "name": "Onboarding flow",
      "description": "Sign-up through first document",
      "viewport": { "x": 0, "y": 0, "zoom": 1 }
    }
  }
}

meta.viewport is the board's deliberate home view, where a reader lands on open. Each user's own scroll position is stored separately, so setting this is a choice about the board, not about you. Omit it and the board opens fit-to-content.

Nodes

Every node needs id (unique, non-empty), type, and x / y / width / height. Geometry is written as integers; the editor rounds on save either way.