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.

Install with Tessl CLI

npx tessl i github:davepoon/buildwithclaude --skill json-canvas

What are skills?

1.12x

Quality

82%

Does it follow best practices?

Impact

96%

1.12x

Average score across 3 eval scenarios

SKILL.md

Review

Evals

JSON Canvas

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.

When to Use This Skill

Creating or editing .canvas files in Obsidian
Building visual mind maps or flowcharts
Creating project boards or planning documents
Organizing notes visually with connections
Building diagrams with linked content

File Structure

A canvas file contains two top-level arrays:

{
  "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

First node = bottom layer (displayed below others) Last node = top layer (displayed above others)

Generic Node 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.

{
  "id": "text1",
  "type": "text",
  "x": 0,
  "y": 0,
  "width": 300,
  "height": 150,
  "text": "# Heading\n\nThis is **markdown** content."
}

File Nodes

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

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

{
  "id": "file1",
  "type": "file",
  "x": 350,
  "y": 0,
  "width": 400,
  "height": 300,
  "file": "Notes/My Note.md",
  "subpath": "#Heading"
}

Link Nodes

Link nodes display external URLs.

{
  "id": "link1",
  "type": "link",
  "x": 0,
  "y": 200,
  "width": 300,
  "height": 150,
  "url": "https://example.com"
}

Group Nodes

Group nodes are visual containers for organizing other nodes.

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

{
  "id": "group1",
  "type": "group",
  "x": -50,
  "y": -50,
  "width": 800,
  "height": 500,
  "label": "Project Ideas",
  "color": "4"
}

Edges

Edges are lines connecting nodes.

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

{
  "id": "edge1",
  "fromNode": "text1",
  "fromSide": "right",
  "toNode": "file1",
  "toSide": "left",
  "toEnd": "arrow",
  "label": "references"
}

Colors

The canvasColor type supports both hex colors and preset options.

Hex Colors

{
  "color": "#FF0000"
}

Preset Colors

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

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

Complete Examples

Simple Canvas with Text and Connections

{
  "nodes": [
    {
      "id": "idea1",
      "type": "text",
      "x": 0,
      "y": 0,
      "width": 250,
      "height": 100,
      "text": "# Main Idea\n\nCore concept goes here"
    },
    {
      "id": "idea2",
      "type": "text",
      "x": 350,
      "y": -50,
      "width": 200,
      "height": 80,
      "text": "## Supporting Point 1\n\nDetails..."
    },
    {
      "id": "idea3",
      "type": "text",
      "x": 350,
      "y": 100,
      "width": 200,
      "height": 80,
      "text": "## Supporting Point 2\n\nMore details..."
    }
  ],
  "edges": [
    {
      "id": "e1",
      "fromNode": "idea1",
      "fromSide": "right",
      "toNode": "idea2",
      "toSide": "left",
      "toEnd": "arrow"
    },
    {
      "id": "e2",
      "fromNode": "idea1",
      "fromSide": "right",
      "toNode": "idea3",
      "toSide": "left",
      "toEnd": "arrow"
    }
  ]
}

Project Board with Groups

{
  "nodes": [
    {
      "id": "todo-group",
      "type": "group",
      "x": 0,
      "y": 0,
      "width": 300,
      "height": 400,
      "label": "To Do",
      "color": "1"
    },
    {
      "id": "progress-group",
      "type": "group",
      "x": 350,
      "y": 0,
      "width": 300,
      "height": 400,
      "label": "In Progress",
      "color": "3"
    },
    {
      "id": "done-group",
      "type": "group",
      "x": 700,
      "y": 0,
      "width": 300,
      "height": 400,
      "label": "Done",
      "color": "4"
    },
    {
      "id": "task1",
      "type": "text",
      "x": 20,
      "y": 50,
      "width": 260,
      "height": 80,
      "text": "## Task 1\n\nDescription of first task"
    },
    {
      "id": "task2",
      "type": "text",
      "x": 370,
      "y": 50,
      "width": 260,
      "height": 80,
      "text": "## Task 2\n\nCurrently working on this"
    },
    {
      "id": "task3",
      "type": "text",
      "x": 720,
      "y": 50,
      "width": 260,
      "height": 80,
      "text": "## Task 3\n\n~~Completed task~~"
    }
  ],
  "edges": []
}

Research Canvas with Files and Links

{
  "nodes": [
    {
      "id": "central",
      "type": "text",
      "x": 200,
      "y": 200,
      "width": 200,
      "height": 100,
      "text": "# Research Topic\n\nMain research question",
      "color": "6"
    },
    {
      "id": "notes1",
      "type": "file",
      "x": 0,
      "y": 0,
      "width": 180,
      "height": 150,
      "file": "Research/Literature Review.md"
    },
    {
      "id": "notes2",
      "type": "file",
      "x": 450,
      "y": 0,
      "width": 180,
      "height": 150,
      "file": "Research/Methodology.md"
    },
    {
      "id": "source1",
      "type": "link",
      "x": 0,
      "y": 350,
      "width": 180,
      "height": 100,
      "url": "https://scholar.google.com"
    },
    {
      "id": "source2",
      "type": "link",
      "x": 450,
      "y": 350,
      "width": 180,
      "height": 100,
      "url": "https://arxiv.org"
    }
  ],
  "edges": [
    {
      "id": "e1",
      "fromNode": "central",
      "toNode": "notes1",
      "toEnd": "arrow",
      "label": "literature"
    },
    {
      "id": "e2",
      "fromNode": "central",
      "toNode": "notes2",
      "toEnd": "arrow",
      "label": "methods"
    },
    {
      "id": "e3",
      "fromNode": "central",
      "toNode": "source1",
      "toEnd": "arrow"
    },
    {
      "id": "e4",
      "fromNode": "central",
      "toNode": "source2",
      "toEnd": "arrow"
    }
  ]
}

Flowchart

{
  "nodes": [
    {
      "id": "start",
      "type": "text",
      "x": 100,
      "y": 0,
      "width": 150,
      "height": 60,
      "text": "**Start**",
      "color": "4"
    },
    {
      "id": "decision",
      "type": "text",
      "x": 75,
      "y": 120,
      "width": 200,
      "height": 80,
      "text": "## Decision\n\nIs condition true?",
      "color": "3"
    },
    {
      "id": "yes-path",
      "type": "text",
      "x": -100,
      "y": 280,
      "width": 150,
      "height": 60,
      "text": "**Yes Path**\n\nDo action A"
    },
    {
      "id": "no-path",
      "type": "text",
      "x": 300,
      "y": 280,
      "width": 150,
      "height": 60,
      "text": "**No Path**\n\nDo action B"
    },
    {
      "id": "end",
      "type": "text",
      "x": 100,
      "y": 420,
      "width": 150,
      "height": 60,
      "text": "**End**",
      "color": "1"
    }
  ],
  "edges": [
    {
      "id": "e1",
      "fromNode": "start",
      "fromSide": "bottom",
      "toNode": "decision",
      "toSide": "top",
      "toEnd": "arrow"
    },
    {
      "id": "e2",
      "fromNode": "decision",
      "fromSide": "left",
      "toNode": "yes-path",
      "toSide": "top",
      "toEnd": "arrow",
      "label": "Yes"
    },
    {
      "id": "e3",
      "fromNode": "decision",
      "fromSide": "right",
      "toNode": "no-path",
      "toSide": "top",
      "toEnd": "arrow",
      "label": "No"
    },
    {
      "id": "e4",
      "fromNode": "yes-path",
      "fromSide": "bottom",
      "toNode": "end",
      "toSide": "left",
      "toEnd": "arrow"
    },
    {
      "id": "e5",
      "fromNode": "no-path",
      "fromSide": "bottom",
      "toNode": "end",
      "toSide": "right",
      "toEnd": "arrow"
    }
  ]
}

ID Generation

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

Example format: a1b2c3d4e5f67890

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

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

References

Repository: davepoon/buildwithclaude
Commit: 8768d36
Last updated: 1 day ago
Created: 1 day ago

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