json-canvas

json-canvas is a skill for Claude Code, Codex from kv0906/pm-kit. It costs 54 tokens per session (5,006 once invoked), scanned A, a copy of json-canvas, MIT.

A tool for creating and editing JSON Canvas files, which are open-format files used for visual layouts such as mind maps and flowcharts. It works with text, file, link, and group nodes connected by edges.

In plain words
What is it for?
Creating mind maps, flowcharts, visual notes, linked file layouts, and other `.canvas` files with nodes, groups, and connections.
Why use it?
It lets an agent represent connected ideas and references in a structured canvas that Obsidian and other compatible apps can read.

Skill for Claude CodeCodex

Part of the pm-kit plugin — 35 skills, 7 agents, 2 hooks shipped together

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/kv0906/pm-kit/json-canvas
Any agent
npx skills add kv0906/pm-kit --skill json-canvas
Clone the repo
git clone --depth 1 https://github.com/kv0906/pm-kit

Made for: Claude Code, Codex.

Or install pm-kit, the plugin that ships this one along with the rest of its 35 skills, 7 agents, 2 hooks.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for json-canvas

README.md
[![agentmods](https://agentmods.dev/badge/skills/kv0906/pm-kit/json-canvas.svg)](https://agentmods.dev/skills/kv0906/pm-kit/json-canvas)
Your own site
<a href="https://agentmods.dev/skills/kv0906/pm-kit/json-canvas"><img src="https://agentmods.dev/badge/skills/kv0906/pm-kit/json-canvas.svg" alt="Measured on agentmods" height="20"></a>
Per session 54 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,006 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 95% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00054 $0.05006
Opus 5 $0.00027 $0.02503
Sonnet 5 $0.00011 $0.01001
Haiku 4.5 $0.00005 $0.00501

Measured 4d ago against content hash 10673ba00ef8, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

json-canvas scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

95% identical to json-canvas — 3 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.claude/skills/json-canvas/SKILL.md · 644 lines

How it starts

The opening of the file, as written. The whole thing — 644 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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"
}

Read the full file on GitHub · 644 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 4d ago First seen · 644 lines · 54 tokens per session scan A 10673ba00ef8

Subscribe to this mod's changes

json-canvas is a skill published in the GitHub repository kv0906/pm-kit (133 stars, last pushed 2mo ago), licensed MIT. It adds 54 tokens to every session and 5,006 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 95% identical to json-canvas, differing in 3 lines, and is treated as a copy.

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