# JSON Canvas

> 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.

- Skill: `yeaight7/json-canvas` (Agent Skill)
- Install (CLI): `npx skillmds@latest add yeaight7/json-canvas`
- Raw SKILL.md: https://api.skillmd.com/api/skills/yeaight7/json-canvas/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: yeaight7 (https://skillmd.com/u/yeaight7)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/yeaight7/json-canvas

---


# JSON Canvas Skill

## File Structure

A canvas file (`.canvas`) contains two top-level arrays following the [JSON Canvas Spec 1.0](https://jsoncanvas.org/spec/1.0/):

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

## Common Workflows

### 1. Create a New Canvas

1. Create a `.canvas` file with the base structure `{"nodes": [], "edges": []}`
2. Generate unique 16-character hex IDs for each node (e.g., `"6f0ad84f44ce9c17"`)
3. Add nodes with required fields: `id`, `type`, `x`, `y`, `width`, `height`
4. Add edges referencing valid node IDs via `fromNode` and `toNode`
5. **Validate**: Verify all `fromNode`/`toNode` values exist in the nodes array

### 2. Add a Node to an Existing Canvas

1. Read and parse the existing `.canvas` file
2. Generate a unique ID that does not collide with existing IDs
3. Choose position (`x`, `y`) that avoids overlapping existing nodes (50-100px spacing)
4. Append the new node object to the `nodes` array
5. **Validate**: Confirm all IDs are unique and all edge references resolve

### 3. Connect Two Nodes

1. Identify the source and target node IDs
2. Generate a unique edge ID
3. Set `fromNode` and `toNode` to the source and target IDs
4. Optionally set `fromSide`/`toSide` (`top`, `right`, `bottom`, `left`) and `label`
5. **Validate**: Confirm both IDs reference existing nodes

## Nodes

Nodes are objects placed on the canvas. Array order determines z-index (first = bottom layer).

### Generic Node Attributes

| Attribute | Required | Type | Description |
|-----------|----------|------|-------------|
| `id` | Yes | string | Unique 16-char hex identifier |
| `type` | Yes | string | `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 | string | Preset `"1"`-`"6"` or hex (e.g., `"#FF0000"`) |

### Text Node

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

**Newline pitfall**: Use `\n` in JSON strings. Do **not** use literal `\\n`.

### File Node

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

### Link Node

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

### Group Node

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

## Edges

| Attribute | Required | Default | Description |
|-----------|----------|---------|-------------|
| `id` | Yes | - | Unique identifier |
| `fromNode` | Yes | - | Source node ID |
| `toNode` | Yes | - | Target node ID |
| `fromSide` | No | - | `top`, `right`, `bottom`, or `left` |
| `toSide` | No | - | `top`, `right`, `bottom`, or `left` |
| `fromEnd` | No | `none` | `none` or `arrow` |
| `toEnd` | No | `arrow` | `none` or `arrow` |
| `color` | No | - | Line color |
| `label` | No | - | Text label |

```json
{
  "id": "0123456789abcdef",
  "fromNode": "6f0ad84f44ce9c17",
  "fromSide": "right",
  "toNode": "a1b2c3d4e5f67890",
  "toSide": "left",
  "label": "leads to"
}
```

## Colors

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

## Layout Guidelines

- Coordinates can be negative (canvas extends infinitely)
- `x` increases right, `y` increases down; position is the top-left corner
- Space nodes 50-100px apart; leave 20-50px padding inside groups
- Align to grid (multiples of 10 or 20) for cleaner layouts

| Node Type | Suggested Width | Suggested Height |
|-----------|-----------------|------------------|
| Small text | 200-300 | 80-150 |
| Medium text | 300-450 | 150-300 |
| Large text | 400-600 | 300-500 |

## Validation Checklist

After creating or editing a canvas file:

1. All `id` values are unique across both nodes and edges
2. Every `fromNode` and `toNode` references an existing node ID
3. Required fields are present for each node type
4. `type` is one of: `text`, `file`, `link`, `group`
5. Side values are one of: `top`, `right`, `bottom`, `left`
6. End values are one of: `none`, `arrow`
7. JSON is valid and parseable

## References

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