toon-format

toon-format is a skill for Claude Code from closedloop-ai/claude-plugins. It costs 66 tokens per session (685 once invoked), scanned A, original, Apache-2.0.

A guide for writing and reading TOON files, a compact text format that represents the same data as JSON. It covers arrays, objects, quoting, indentation, and conversion between JSON and TOON.

In plain words
What is it for?
Use it when editing .toon files, creating org-patterns.toon, or converting data between JSON and TOON.
Why use it?
It helps prevent malformed files and inconsistent syntax when using this format for data in AI prompts or project files.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: mentions subagents.

Part of the self-learning plugin — 2 skills, 6 commands shipped together

Good fit Use it when editing .toon files, creating org-patterns.toon, or converting data between JSON and TOON.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/closedloop-ai/claude-plugins/toon-format
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.

Any agent
npx skills add closedloop-ai/claude-plugins --skill toon-format
Clone the repo
git clone --depth 1 https://github.com/closedloop-ai/claude-plugins

Made for: Claude Code.

Or install self-learning, the plugin that ships this one along with the rest of its 2 skills, 6 commands.

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 toon-format

README.md
[![agentmods](https://agentmods.dev/badge/skills/closedloop-ai/claude-plugins/toon-format/github.svg)](https://agentmods.dev/skills/closedloop-ai/claude-plugins/toon-format)
Your own site
<a href="https://agentmods.dev/skills/closedloop-ai/claude-plugins/toon-format"><img src="https://agentmods.dev/badge/skills/closedloop-ai/claude-plugins/toon-format/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.

agentmods 80×15 button for toon-format

Your own site · 80×15
<a href="https://agentmods.dev/skills/closedloop-ai/claude-plugins/toon-format"><img src="https://agentmods.dev/badge/skills/closedloop-ai/claude-plugins/toon-format.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 66 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 685 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found 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 5.1 $0.00066 $0.00685
Opus 5 $0.00033 $0.00342
Sonnet 5 $0.00013 $0.00137
Haiku 4.5 $0.00007 $0.00068

Measured yesterday against content hash 311019cc855c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

toon-format 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 yesterday.

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.

plugins/self-learning/skills/toon-format/SKILL.md · 86 lines

How it starts

The opening of the file, as written. The whole thing — 86 lines — stays where its author put it; the contents beside it link to each section on GitHub.

TOON Format (Token-Oriented Object Notation)

TOON is a compact, human-readable encoding of the JSON data model optimized for LLM prompts. It achieves ~40% token reduction compared to JSON while maintaining lossless round-trip compatibility.

Core Syntax Rules

Array Declaration

Arrays use bracketed headers with mandatory length count:

tags[3]: admin,ops,dev

Tabular Arrays (Uniform Object Arrays)

For arrays of objects with identical structure, use field headers in braces:

patterns[2]{id,category,summary}:
  P-001,pattern,"Use tokens for colors"
  P-002,mistake,"Check auth before routes"
  • Field names declared once in {...} after the count
  • Each row contains values in declared field order
  • Rows indented with 2 spaces (NEVER tabs)

Objects

Objects use indentation-based nesting (2 spaces per level):

user:
  id: 123
  name: Ada

Quoting Rules (Critical)

Strings MUST be quoted if they contain:

  • The active delimiter (comma by default)
  • Empty string, leading/trailing whitespace
  • Reserved literals (true, false, null)
  • Numeric-like patterns
  • Colons, quotes, backslashes, brackets, braces
  • Control characters or leading hyphens

Escape sequences: \\, \", \n, \r, \t

org-patterns.toon Format

Standard format for ClosedLoop organization learnings:

patterns[N]{id,category,summary,confidence,seen_count,success_rate,flags,applies_to,context,repo}:
  P-001,pattern,"Summary here",high,5,0.85,,implementation-subagent,UI|styling,*
  P-002,mistake,"Check auth before routes",medium,3,0.60,[REVIEW],*,auth|routes,astoria-frontend

Field notes:

  • summary - Always quoted (contains natural language with commas)
  • flags - [REVIEW], [STALE], [UNTESTED], [PRUNE], or empty
  • applies_to - Pipe-separated agent names or * for all
  • context - Pipe-separated tags
  • repo - Repository name (derived from git remote basename) or * for all repos

Validation Checklist

Read the full file on GitHub · 86 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. yesterday First seen · 86 lines · 66 tokens per session scan A 311019cc855c

Subscribe to this mod's changes

toon-format is a skill published in the GitHub repository closedloop-ai/claude-plugins (103 stars, last pushed 2d ago), licensed Apache-2.0. It adds 66 tokens to every session and 685 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-07.