json-canvas-editor

name	json-canvas-editor
description	Use when the user wants to create, edit, or repair a JSON Canvas 1.0 `.canvas` file with valid typed nodes, edges, IDs, and readable layout. Do not use for Mermaid, draw.io, generic whiteboards, ordinary JSON cleanup, or visual design work outside the JSON Canvas format.

JSON Canvas Editor

Create and edit JSON Canvas files safely. Keep the focus on valid structure, stable IDs, readable layouts, and reference integrity.

Use this skill when working with .canvas files for mind maps, flowcharts, note graphs, or other JSON Canvas layouts.

Do Not Use For

• draw.io, Mermaid, or other diagram formats
• broad visual design or presentation polish
• freeform brainstorming that does not need a valid .canvas file
• general JSON cleanup that is unrelated to JSON Canvas structure
• viewing or rendering an existing canvas when no structural change is requested

Workflow

1. Confirm the canvas job and source file:

   • identify whether you are creating a new canvas or editing an existing one
   • read the target .canvas file before changing anything
   • if the user did not provide a file, ask for the path or the desired canvas content

2. Preserve the JSON Canvas shape:

   • keep a top-level object; JSON Canvas 1.0 permits nodes and edges to be omitted, but each must be an array when present
   • use the official JSON Canvas 1.0 specification as the field authority and avoid adding fields that are not needed for the requested canvas

3. Edit nodes carefully:

   • require every node to have a string id unique among nodes, a supported type, and integer x, y, width, and height
   • use only the standard node types text, file, link, and group unless the target application explicitly documents an extension
   • require text for text nodes, file for file nodes, and url for link nodes; keep group-only fields on group nodes
   • set x, y, width, and height so nodes do not overlap unless overlap is intentional
   • keep node text short enough to read inside the chosen size

4. Wire edges with valid references:

   • give every edge a string id unique among edges; prefer IDs that also avoid node-ID collisions for interoperability, but do not reject an otherwise valid file on that preference alone
   • require string fromNode and toNode values
   • connect only existing node IDs
   • do not leave dangling fromNode or toNode values
   • keep edge metadata minimal unless labels or styling are required

5. Lay out the graph for clarity:

   • space related nodes in rows, columns, or clusters
   • leave enough room for labels and edge routing
   • group connected nodes near each other instead of scattering them across the canvas

6. Validate before finishing:

   • parse the file as JSON
   • confirm nodes and edges are arrays when present and every object has its type-appropriate required fields
   • confirm node IDs are unique among nodes and edge IDs are unique among edges
   • confirm every fromNode and toNode resolves to a real node and no edge is dangling
   • confirm standard enum-like values such as node type, side, end shape, and group background style match JSON Canvas 1.0 when present
   • open the file in the intended canvas application when feasible; otherwise state that only structural validation was performed

Output Expectations

• Return the edited .canvas content or the exact file path that was updated.
• Call out any validation issue that blocks saving the file.
• State which validation checks were run when the canvas was repaired or heavily changed.
• State whether validation covered JSON parsing, JSON Canvas 1.0 required fields, node/edge collection ID uniqueness, edge resolution, and an application-open check.
• If the canvas had to be simplified, say which nodes or edges were reduced or removed.

Guardrails

• Do not rename IDs unless the change is necessary and the references are updated too.
• Do not convert the file into a general drawing format.
• Do not guess about missing nodes or edges when the source canvas is incomplete.
• Do not add styling noise when the job is about structure and correctness.