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.
npx skills add julianobarbosa/claude-code-skills --skill json-canvasgit clone --depth 1 https://github.com/julianobarbosa/claude-code-skillsWrote 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.
[](https://agentmods.dev/skills/julianobarbosa/claude-code-skills/json-canvas)<a href="https://agentmods.dev/skills/julianobarbosa/claude-code-skills/json-canvas"><img src="https://agentmods.dev/badge/skills/julianobarbosa/claude-code-skills/json-canvas/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/julianobarbosa/claude-code-skills/json-canvas"><img src="https://agentmods.dev/badge/skills/julianobarbosa/claude-code-skills/json-canvas.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00054 | $0.05341 |
| Opus 5 | $0.00027 | $0.02670 |
| Sonnet 5 | $0.00011 | $0.01068 |
| Haiku 4.5 | $0.00005 | $0.00534 |
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 9d 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.
This is a copy
94% identical to json-canvas — 14 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.
How it starts
The opening of the file, as written. The whole thing — 655 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 objectsedges(optional): Array of edge objects connecting nodes
Nodes
Nodes are objects placed on the canvas. There are four node types:
text- Text content with Markdownfile- Reference to files/attachmentslink- External URLgroup- 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"
}
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.
- 9d ago First seen · 655 lines · 54 tokens per session scan A b371f3fb5955
json-canvas is a skill published in the GitHub repository julianobarbosa/claude-code-skills (10 stars, last pushed 13d ago), licensed MIT. It adds 54 tokens to every session and 5,341 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 94% identical to json-canvas, differing in 14 lines, and is treated as a copy.
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