JSON Canvas Skill

File Structure

A canvas file (

.canvas

) contains two top-level arrays following the JSON Canvas Spec 1.0:

json

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

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

Common Workflows

1. Create a New Canvas

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

2. Add a Node to an Existing Canvas

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

3. Connect Two Nodes

Identify the source and target node IDs
Generate a unique edge ID
Set
```
fromNode
```
and
```
toNode
```
to the source and target IDs
Optionally set
```
fromSide
```
/
```
toSide
```
(top, right, bottom, left) for anchor points
Optionally set
```
label
```
for descriptive text on the edge
Append the edge to the
```
edges
```
array
Validate: Confirm both
```
fromNode
```
and
```
toNode
```
reference existing node IDs

4. Edit an Existing Canvas

Read and parse the
```
.canvas
```
file as JSON
Locate the target node or edge by
```
id
```
Modify the desired attributes (text, position, color, etc.)
Write the updated JSON back to the file
Validate: Re-check all ID uniqueness and edge reference integrity after editing

Nodes

Nodes are objects placed on the canvas. Array order determines z-index: first node = bottom layer, last node = top 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	canvasColor	Preset `"1"` - `"6"` or hex (e.g., `"#FF0000"` )

Text Nodes

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

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

for line breaks in JSON strings. Do not use the literal

\\n

-- Obsidian renders that as the characters

and

File Nodes

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

json

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

Link Nodes

Attribute	Required	Type	Description
`url`	Yes	string	External URL

json

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

Group Nodes

Groups are visual containers for organizing other nodes. Position child nodes inside the group's bounds.

Attribute	Required	Type	Description
`label`	No	string	Text label for the group
`background`	No	string	Path to background image
`backgroundStyle`	No	string	`cover` , `ratio` , or `repeat`

json

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

Edges

Edges connect nodes via

fromNode

and

toNode

IDs.

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

json

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

Colors

The

canvasColor

type accepts either a hex string or a preset number:

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

Preset color values are intentionally undefined -- applications use their own brand colors.

ID Generation

Generate 16-character lowercase hexadecimal strings (64-bit random value):

"6f0ad84f44ce9c17"
"a3b2c1d0e9f8a7b6"

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
File preview	300-500	200-400
Link preview	250-400	100-200

Validation Checklist

After creating or editing a canvas file, verify:

All
```
id
```
values are unique across both nodes and edges
Every
```
fromNode
```
and
```
toNode
```
references an existing node ID
Required fields are present for each node type (
```
text
```
for text nodes,
```
file
```
for file nodes,
```
url
```
for link nodes)
```
type
```
is one of:
```
text
```
,
```
file
```
,
```
link
```
,
```
group
```
```
fromSide
```
/
```
toSide
```
values are one of:
```
top
```
,
```
right
```
,
```
bottom
```
,
```
left
```
```
fromEnd
```
/
```
toEnd
```
values are one of:
```
none
```
,
```
arrow
```
Color presets are
```
"1"
```
through
```
"6"
```
or valid hex (e.g.,
```
"#FF0000"
```
)
JSON is valid and parseable

If validation fails, check for duplicate IDs, dangling edge references, or malformed JSON strings (especially unescaped newlines in text content).

Complete Examples

See references/EXAMPLES.md for full canvas examples including mind maps, project boards, research canvases, and flowcharts.

json-canvas

NPX Install

SKILL.md Content

JSON Canvas Skill

File Structure

Common Workflows

1. Create a New Canvas

2. Add a Node to an Existing Canvas

3. Connect Two Nodes

4. Edit an Existing Canvas

Nodes

Generic Node Attributes

Text Nodes

File Nodes

Link Nodes

Group Nodes

Edges

Colors

ID Generation

Layout Guidelines

Validation Checklist

Complete Examples

References