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json-canvas skill

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This skill helps you create and edit JSON Canvas files (.canvas) with nodes, edges, and groups for visual brainstorming.

This is most likely a fork of the json-canvas skill from kepano

npx playbooks add skill bahayonghang/my-claude-code-settings --skill json-canvas

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---
name: json-canvas
description: Create and edit JSON Canvas files (.canvas) with nodes, edges, groups, and connections. Use when working with .canvas files, creating visual canvases, mind maps, flowcharts, or when the user mentions Canvas files in Obsidian.
---

# JSON Canvas Skill

This skill enables skills-compatible agents 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](https://jsoncanvas.org/spec/1.0/).

## File Structure

A canvas file contains two top-level arrays:

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

- `nodes` (optional): Array of node objects
- `edges` (optional): Array of edge objects connecting nodes

## Nodes

Nodes are objects placed on the canvas. There are four node types:
- `text` - Text content with Markdown
- `file` - Reference to files/attachments
- `link` - External URL
- `group` - Visual container for other nodes

### Z-Index Ordering

Nodes are ordered by z-index in the array:
- First node = bottom layer (displayed below others)
- Last node = top layer (displayed above others)

### Generic Node Attributes

All nodes share these attributes:

| Attribute | Required | Type | Description |
|-----------|----------|------|-------------|
| `id` | Yes | string | Unique identifier for the node |
| `type` | Yes | string | Node type: `text`, `file`, `link`, or `group` |
| `x` | Yes | integer | X position in pixels |
| `y` | Yes | integer | Y position in pixels |
| `width` | Yes | integer | Width in pixels |
| `height` | Yes | integer | Height in pixels |
| `color` | No | canvasColor | Node color (see Color section) |

### Text Nodes

Text nodes contain Markdown content.

```json
{
  "id": "6f0ad84f44ce9c17",
  "type": "text",
  "x": 0,
  "y": 0,
  "width": 400,
  "height": 200,
  "text": "# Hello World\n\nThis is **Markdown** content."
}
```

#### Newline Escaping (Common Pitfall)

In JSON, newline characters inside strings **must** be represented as `\n`. Do **not** use the literal sequence `\\n` in a `.canvas` file—Obsidian will render it as the characters `\` and `n` instead of a line break.

Examples:

```json
{ "type": "text", "text": "Line 1\nLine 2" }
```

```json
{ "type": "text", "text": "Line 1\\nLine 2" }
```

| Attribute | Required | Type | Description |
|-----------|----------|------|-------------|
| `text` | Yes | string | Plain text with Markdown syntax |

### File Nodes

File nodes reference files or attachments (images, videos, PDFs, notes, etc.).

```json
{
  "id": "a1b2c3d4e5f67890",
  "type": "file",
  "x": 500,
  "y": 0,
  "width": 400,
  "height": 300,
  "file": "Attachments/diagram.png"
}
```

```json
{
  "id": "b2c3d4e5f6789012",
  "type": "file",
  "x": 500,
  "y": 400,
  "width": 400,
  "height": 300,
  "file": "Notes/Project Overview.md",
  "subpath": "#Implementation"
}
```

| Attribute | Required | Type | Description |
|-----------|----------|------|-------------|
| `file` | Yes | string | Path to file within the system |
| `subpath` | No | string | Link to heading or block (starts with `#`) |

### Link Nodes

Link nodes display external URLs.

```json
{
  "id": "c3d4e5f678901234",
  "type": "link",
  "x": 1000,
  "y": 0,
  "width": 400,
  "height": 200,
  "url": "https://obsidian.md"
}
```

| Attribute | Required | Type | Description |
|-----------|----------|------|-------------|
| `url` | Yes | string | External URL |

### Group Nodes

Group nodes are visual containers for organizing other nodes.

```json
{
  "id": "d4e5f6789012345a",
  "type": "group",
  "x": -50,
  "y": -50,
  "width": 1000,
  "height": 600,
  "label": "Project Overview",
  "color": "4"
}
```

```json
{
  "id": "e5f67890123456ab",
  "type": "group",
  "x": 0,
  "y": 700,
  "width": 800,
  "height": 500,
  "label": "Resources",
  "background": "Attachments/background.png",
  "backgroundStyle": "cover"
}
```

| Attribute | Required | Type | Description |
|-----------|----------|------|-------------|
| `label` | No | string | Text label for the group |
| `background` | No | string | Path to background image |
| `backgroundStyle` | No | string | Background rendering style |

#### Background Styles

| Value | Description |
|-------|-------------|
| `cover` | Fills entire width and height of node |
| `ratio` | Maintains aspect ratio of background image |
| `repeat` | Repeats image as pattern in both directions |

## Edges

Edges are lines connecting nodes.

```json
{
  "id": "f67890123456789a",
  "fromNode": "6f0ad84f44ce9c17",
  "toNode": "a1b2c3d4e5f67890"
}
```

```json
{
  "id": "0123456789abcdef",
  "fromNode": "6f0ad84f44ce9c17",
  "fromSide": "right",
  "fromEnd": "none",
  "toNode": "b2c3d4e5f6789012",
  "toSide": "left",
  "toEnd": "arrow",
  "color": "1",
  "label": "leads to"
}
```

| Attribute | Required | Type | Default | Description |
|-----------|----------|------|---------|-------------|
| `id` | Yes | string | - | Unique identifier for the edge |
| `fromNode` | Yes | string | - | Node ID where connection starts |
| `fromSide` | No | string | - | Side where edge starts |
| `fromEnd` | No | string | `none` | Shape at edge start |
| `toNode` | Yes | string | - | Node ID where connection ends |
| `toSide` | No | string | - | Side where edge ends |
| `toEnd` | No | string | `arrow` | Shape at edge end |
| `color` | No | canvasColor | - | Line color |
| `label` | No | string | - | Text label for the edge |

### Side Values

| Value | Description |
|-------|-------------|
| `top` | Top edge of node |
| `right` | Right edge of node |
| `bottom` | Bottom edge of node |
| `left` | Left edge of node |

### End Shapes

| Value | Description |
|-------|-------------|
| `none` | No endpoint shape |
| `arrow` | Arrow endpoint |

## Colors

The `canvasColor` type can be specified in two ways:

### Hex Colors

```json
{
  "color": "#FF0000"
}
```

### Preset Colors

```json
{
  "color": "1"
}
```

| Preset | Color |
|--------|-------|
| `"1"` | Red |
| `"2"` | Orange |
| `"3"` | Yellow |
| `"4"` | Green |
| `"5"` | Cyan |
| `"6"` | Purple |

Note: Specific color values for presets are intentionally undefined, allowing applications to use their own brand colors.

## Complete Examples

### Simple Canvas with Text and Connections

```json
{
  "nodes": [
    {
      "id": "8a9b0c1d2e3f4a5b",
      "type": "text",
      "x": 0,
      "y": 0,
      "width": 300,
      "height": 150,
      "text": "# Main Idea\n\nThis is the central concept."
    },
    {
      "id": "1a2b3c4d5e6f7a8b",
      "type": "text",
      "x": 400,
      "y": -100,
      "width": 250,
      "height": 100,
      "text": "## Supporting Point A\n\nDetails here."
    },
    {
      "id": "2b3c4d5e6f7a8b9c",
      "type": "text",
      "x": 400,
      "y": 100,
      "width": 250,
      "height": 100,
      "text": "## Supporting Point B\n\nMore details."
    }
  ],
  "edges": [
    {
      "id": "3c4d5e6f7a8b9c0d",
      "fromNode": "8a9b0c1d2e3f4a5b",
      "fromSide": "right",
      "toNode": "1a2b3c4d5e6f7a8b",
      "toSide": "left"
    },
    {
      "id": "4d5e6f7a8b9c0d1e",
      "fromNode": "8a9b0c1d2e3f4a5b",
      "fromSide": "right",
      "toNode": "2b3c4d5e6f7a8b9c",
      "toSide": "left"
    }
  ]
}
```

### Project Board with Groups

```json
{
  "nodes": [
    {
      "id": "5e6f7a8b9c0d1e2f",
      "type": "group",
      "x": 0,
      "y": 0,
      "width": 300,
      "height": 500,
      "label": "To Do",
      "color": "1"
    },
    {
      "id": "6f7a8b9c0d1e2f3a",
      "type": "group",
      "x": 350,
      "y": 0,
      "width": 300,
      "height": 500,
      "label": "In Progress",
      "color": "3"
    },
    {
      "id": "7a8b9c0d1e2f3a4b",
      "type": "group",
      "x": 700,
      "y": 0,
      "width": 300,
      "height": 500,
      "label": "Done",
      "color": "4"
    },
    {
      "id": "8b9c0d1e2f3a4b5c",
      "type": "text",
      "x": 20,
      "y": 50,
      "width": 260,
      "height": 80,
      "text": "## Task 1\n\nImplement feature X"
    },
    {
      "id": "9c0d1e2f3a4b5c6d",
      "type": "text",
      "x": 370,
      "y": 50,
      "width": 260,
      "height": 80,
      "text": "## Task 2\n\nReview PR #123",
      "color": "2"
    },
    {
      "id": "0d1e2f3a4b5c6d7e",
      "type": "text",
      "x": 720,
      "y": 50,
      "width": 260,
      "height": 80,
      "text": "## Task 3\n\n~~Setup CI/CD~~"
    }
  ],
  "edges": []
}
```

### Research Canvas with Files and Links

```json
{
  "nodes": [
    {
      "id": "1e2f3a4b5c6d7e8f",
      "type": "text",
      "x": 300,
      "y": 200,
      "width": 400,
      "height": 200,
      "text": "# Research Topic\n\n## Key Questions\n\n- How does X affect Y?\n- What are the implications?",
      "color": "5"
    },
    {
      "id": "2f3a4b5c6d7e8f9a",
      "type": "file",
      "x": 0,
      "y": 0,
      "width": 250,
      "height": 150,
      "file": "Literature/Paper A.pdf"
    },
    {
      "id": "3a4b5c6d7e8f9a0b",
      "type": "file",
      "x": 0,
      "y": 200,
      "width": 250,
      "height": 150,
      "file": "Notes/Meeting Notes.md",
      "subpath": "#Key Insights"
    },
    {
      "id": "4b5c6d7e8f9a0b1c",
      "type": "link",
      "x": 0,
      "y": 400,
      "width": 250,
      "height": 100,
      "url": "https://example.com/research"
    },
    {
      "id": "5c6d7e8f9a0b1c2d",
      "type": "file",
      "x": 750,
      "y": 150,
      "width": 300,
      "height": 250,
      "file": "Attachments/diagram.png"
    }
  ],
  "edges": [
    {
      "id": "6d7e8f9a0b1c2d3e",
      "fromNode": "2f3a4b5c6d7e8f9a",
      "fromSide": "right",
      "toNode": "1e2f3a4b5c6d7e8f",
      "toSide": "left",
      "label": "supports"
    },
    {
      "id": "7e8f9a0b1c2d3e4f",
      "fromNode": "3a4b5c6d7e8f9a0b",
      "fromSide": "right",
      "toNode": "1e2f3a4b5c6d7e8f",
      "toSide": "left",
      "label": "informs"
    },
    {
      "id": "8f9a0b1c2d3e4f5a",
      "fromNode": "4b5c6d7e8f9a0b1c",
      "fromSide": "right",
      "toNode": "1e2f3a4b5c6d7e8f",
      "toSide": "left",
      "toEnd": "arrow",
      "color": "6"
    },
    {
      "id": "9a0b1c2d3e4f5a6b",
      "fromNode": "1e2f3a4b5c6d7e8f",
      "fromSide": "right",
      "toNode": "5c6d7e8f9a0b1c2d",
      "toSide": "left",
      "label": "visualized by"
    }
  ]
}
```

### Flowchart

```json
{
  "nodes": [
    {
      "id": "a0b1c2d3e4f5a6b7",
      "type": "text",
      "x": 200,
      "y": 0,
      "width": 150,
      "height": 60,
      "text": "**Start**",
      "color": "4"
    },
    {
      "id": "b1c2d3e4f5a6b7c8",
      "type": "text",
      "x": 200,
      "y": 100,
      "width": 150,
      "height": 60,
      "text": "Step 1:\nGather data"
    },
    {
      "id": "c2d3e4f5a6b7c8d9",
      "type": "text",
      "x": 200,
      "y": 200,
      "width": 150,
      "height": 80,
      "text": "**Decision**\n\nIs data valid?",
      "color": "3"
    },
    {
      "id": "d3e4f5a6b7c8d9e0",
      "type": "text",
      "x": 400,
      "y": 200,
      "width": 150,
      "height": 60,
      "text": "Process data"
    },
    {
      "id": "e4f5a6b7c8d9e0f1",
      "type": "text",
      "x": 0,
      "y": 200,
      "width": 150,
      "height": 60,
      "text": "Request new data",
      "color": "1"
    },
    {
      "id": "f5a6b7c8d9e0f1a2",
      "type": "text",
      "x": 400,
      "y": 320,
      "width": 150,
      "height": 60,
      "text": "**End**",
      "color": "4"
    }
  ],
  "edges": [
    {
      "id": "a6b7c8d9e0f1a2b3",
      "fromNode": "a0b1c2d3e4f5a6b7",
      "fromSide": "bottom",
      "toNode": "b1c2d3e4f5a6b7c8",
      "toSide": "top"
    },
    {
      "id": "b7c8d9e0f1a2b3c4",
      "fromNode": "b1c2d3e4f5a6b7c8",
      "fromSide": "bottom",
      "toNode": "c2d3e4f5a6b7c8d9",
      "toSide": "top"
    },
    {
      "id": "c8d9e0f1a2b3c4d5",
      "fromNode": "c2d3e4f5a6b7c8d9",
      "fromSide": "right",
      "toNode": "d3e4f5a6b7c8d9e0",
      "toSide": "left",
      "label": "Yes",
      "color": "4"
    },
    {
      "id": "d9e0f1a2b3c4d5e6",
      "fromNode": "c2d3e4f5a6b7c8d9",
      "fromSide": "left",
      "toNode": "e4f5a6b7c8d9e0f1",
      "toSide": "right",
      "label": "No",
      "color": "1"
    },
    {
      "id": "e0f1a2b3c4d5e6f7",
      "fromNode": "e4f5a6b7c8d9e0f1",
      "fromSide": "top",
      "fromEnd": "none",
      "toNode": "b1c2d3e4f5a6b7c8",
      "toSide": "left",
      "toEnd": "arrow"
    },
    {
      "id": "f1a2b3c4d5e6f7a8",
      "fromNode": "d3e4f5a6b7c8d9e0",
      "fromSide": "bottom",
      "toNode": "f5a6b7c8d9e0f1a2",
      "toSide": "top"
    }
  ]
}
```

## ID Generation

Node and edge IDs must be unique strings. Obsidian generates 16-character hexadecimal IDs:

```json
"id": "6f0ad84f44ce9c17"
"id": "a3b2c1d0e9f8g7h6"
"id": "1234567890abcdef"
```

This format is a 16-character lowercase hex string (64-bit random value).

## Layout Guidelines

### Positioning

- Coordinates can be negative (canvas extends infinitely)
- `x` increases to the right
- `y` increases downward
- Position refers to top-left corner of node

### Recommended Sizes

| Node Type | Suggested Width | Suggested Height |
|-----------|-----------------|------------------|
| Small text | 200-300 | 80-150 |
| Medium text | 300-450 | 150-300 |
| Large text | 400-600 | 300-500 |
| File preview | 300-500 | 200-400 |
| Link preview | 250-400 | 100-200 |
| Group | Varies | Varies |

### Spacing

- Leave 20-50px padding inside groups
- Space nodes 50-100px apart for readability
- Align nodes to grid (multiples of 10 or 20) for cleaner layouts

## Validation Rules

1. All `id` values must be unique across nodes and edges
2. `fromNode` and `toNode` must reference existing node IDs
3. Required fields must be present for each node type
4. `type` must be one of: `text`, `file`, `link`, `group`
5. `backgroundStyle` must be one of: `cover`, `ratio`, `repeat`
6. `fromSide`, `toSide` must be one of: `top`, `right`, `bottom`, `left`
7. `fromEnd`, `toEnd` must be one of: `none`, `arrow`
8. Color presets must be `"1"` through `"6"` or valid hex color

## References

- [JSON Canvas Spec 1.0](https://jsoncanvas.org/spec/1.0/)
- [JSON Canvas GitHub](https://github.com/obsidianmd/jsoncanvas)

Overview

This skill creates and edits JSON Canvas (.canvas) files used by Obsidian and other infinite-canvas tools. It generates valid JSON structures for nodes, edges, groups, files, and links so you can build mind maps, flowcharts, and visual boards programmatically. It enforces common validation rules and helps avoid pitfalls like incorrect newline escaping.

How this skill works

The skill builds and modifies the top-level JSON object with `nodes` and `edges` arrays, producing canvas files that follow JSON Canvas Spec 1.0 conventions. It creates node objects (text, file, link, group) with required spatial properties and optional styling, and edge objects that reference node IDs and connection metadata. It validates IDs, references, required fields, side/end values, background styles, and color formats before output.

When to use it

Generate a new .canvas file from a text outline or structured data
Programmatically update nodes, move them, or change z-ordering
Create flowcharts, mind maps, and project boards for Obsidian canvases
Link files, headings, or external URLs inside a visual canvas
Validate and fix existing .canvas files to meet spec rules

Best practices

Always use unique 16-character hexadecimal IDs for nodes and edges
Escape newlines in text node strings as \n (not literal backslash-n sequences)
Keep nodes spaced 50–100px apart and align to a 10/20px grid for readability
Use groups for organizing related nodes and include 20–50px padding inside groups
Prefer preset color codes "1"–"6" for consistent theming or use hex for explicit colors

Example use cases

Create a research canvas linking PDFs, notes, and web resources with labeled edges
Build a Kanban-style project board using group nodes and colored task cards
Convert an outline to a mind map with central text node and connected supporting nodes
Produce a flowchart with decision nodes, labeled edges, and arrow endpoints
Batch-update positions, widths, or colors for many nodes in a single edit

FAQ

What must I watch for with multiline text?

Use actual newline characters encoded as \n inside JSON strings; do not insert literal \n sequences.

How do I ensure edges reference valid nodes?

Validate that every `fromNode` and `toNode` matches an existing node `id` before saving the file.