JSON Canvas Skill

This skill enables Claude Code to create and edit valid JSON Canvas files (.canvas) used in Obsidian and other applications.

Overview

JSON Canvas is an open file format for infinite canvas data. Canvas files use the .canvas extension and contain valid JSON following the JSON Canvas Spec 1.0.

File Structure

{
  "nodes": [],
  "edges": []
}

• nodes: Array of node objects (optional)
• edges: Array of edge objects (optional)

Node Types

Text Node

{
  "id": "unique-id",
  "type": "text",
  "x": 0,
  "y": 0,
  "width": 250,
  "height": 100,
  "text": "# Heading\n\nMarkdown **content**"
}

File Node

{
  "id": "unique-id",
  "type": "file",
  "x": 300,
  "y": 0,
  "width": 250,
  "height": 100,
  "file": "path/to/file.md",
  "subpath": "#Heading"  // Optional
}

Link Node

{
  "id": "unique-id",
  "type": "link",
  "x": 600,
  "y": 0,
  "width": 250,
  "height": 100,
  "url": "https://example.com"
}

Group Node

{
  "id": "unique-id",
  "type": "group",
  "x": -50,
  "y": -50,
  "width": 1000,
  "height": 300,
  "label": "Group Label",
  "color": "4"
}

Edges

Edges connect nodes with arrows or lines.

{
  "id": "unique-id",
  "from": "node-id-1",
  "to": "node-id-2",
  "fromEnd": "arrow",
  "toEnd": "none",
  "color": "5"
}

End Shapes

• none – No arrow
• arrow – Arrowhead

Side Values

• top, right, bottom, left, none

Colors

Preset colors: "1" through "6" (red, orange, yellow, green, blue, purple)

Quick Example

{
  "nodes": [
    {
      "id": "1",
      "type": "text",
      "x": 0,
      "y": 0,
      "width": 250,
      "height": 100,
      "text": "# Start\n\nBeginning of flow"
    },
    {
      "id": "2",
      "type": "text",
      "x": 400,
      "y": 0,
      "width": 250,
      "height": 100,
      "text": "# End\n\nConclusion"
    }
  ],
  "edges": [
    {
      "id": "e1",
      "from": "1",
      "to": "2",
      "fromEnd": "arrow",
      "toEnd": "arrow"
    }
  ]
}

ID Generation

• Use 16-character hexadecimal IDs: a1b2c3d4e5f6g7h8
• Or use UUID v4: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx
• Must be unique within the canvas

Layout Guidelines

Positioning

• Start at (0, 0) for first node
• Space nodes: 400px horizontal, 200px vertical
• Center text nodes: width 250-300px

Recommended Sizes

• Text nodes: 250×100 to 400×300
• File nodes: 300×200
• Link nodes: 250×100
• Groups: Large enough to contain children + 50px padding

Spacing

• 50px between connected nodes
• 100px between unconnected nodes

Validation Rules

Required Fields

• All nodes must have: id, type, x, y, width, height
• Text nodes: must have text
• File nodes: must have file
• Link nodes: must have url

Edge Requirements

• from and to must reference existing node IDs
• id must be unique across all edges

Common Mistakes

• ❌ Using label for text nodes (use text field)
• ❌ Missing type field
• ❌ Invalid node IDs in edges
• ❌ Negative width/height

Important Notes

1. Z-index: Node order in array determines layering (last = top)
2. Text vs label: Text nodes use text field, groups use label field
3. Edge directions: fromEnd is at the source node, toEnd is at the target
4. File paths: Use forward slashes, relative to vault root

Detailed Documentation

For complete examples and advanced patterns, see REFERENCE.md:

• Complete canvas examples (mind maps, flowcharts, project boards)
• Advanced node configurations
• Edge styling and routing
• Group nesting and layouts