json-canvas

Q: How do I install json-canvas?

Run npx skills add https://github.com/julianobarbosa/claude-code-skills --skill json-canvas in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/json-canvas/ (personal) or .claude/skills/json-canvas/ (project).

by julianobarbosaProductivity & Automation

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.

Installs: 102
Last 24h: —
Trending rank: —
Security: Not audited

Install

Works with every agent the skills CLI supports.

npx skills add https://github.com/julianobarbosa/claude-code-skills --skill json-canvas

01
Install
Run the command in your project. The CLI asks which agents to install for.
02
Describe the task
Ask your agent for something this skill covers. It loads json-canvas automatically when relevant.
03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.

SKILL.md

The instructions your agent reads when the skill is triggered.

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

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

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.

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

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.).

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

{
  "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.

{
  "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.

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

{
  "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.

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

{
  "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

{
  "color": "#FF0000"
}

Preset Colors

{
  "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

{
  "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

{
  "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

{
  "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

{
  "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:

"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

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

Gotchas

Node array order IS the z-index: Editors reading .canvas render array[0] at the bottom and array[-1] on top. Reordering the JSON to "clean up" silently flips which node covers which — visual diff is non-obvious until you open the file.
fromNode/toNode must reference existing IDs but JSON has no foreign-key enforcement: Deleting a node without sweeping edges leaves orphan edges. Obsidian shows them as connections to nowhere; some apps silently drop them, others throw. Validate edges after every node removal.
Coordinates are pixels with no DPI awareness: A canvas designed on retina (logical px) renders differently on a 1x display. There's no scale field — pre-compute sizes against a known reference and accept rendering drift across machines.
16-char hex IDs are conventional, not required by spec: Any unique string works. But Obsidian's "duplicate node" feature regenerates 16-char hex — mixing UUIDs and hex IDs in the same file makes manual edits painful when grepping.
subpath requires the # prefix and is case-sensitive in some apps: subpath: "Heading" fails silently; "#Heading" works; "#heading" may or may not — depends on whether the target file's heading is exactly that case.
Group nodes don't own their children — coordinates do: Moving a group does NOT move the nodes inside it. They're only visually inside because their x/y happen to fall within the group's bounding box. Bulk-move requires updating every child's coordinates.

FAQ

What does the json-canvas skill do?

How do I install json-canvas?

Run npx skills add https://github.com/julianobarbosa/claude-code-skills --skill json-canvas in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/json-canvas/ (personal) or .claude/skills/json-canvas/ (project).

Which AI agents can use json-canvas?

Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.

Is json-canvas safe to install?

No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.

Who maintains json-canvas?

It is published by julianobarbosa in julianobarbosa/claude-code-skills. It has 102 recorded installs.