TOON
Token-Oriented Object Notation: compact JSON-like format for LLM prompts.
How TOON is used
TOON is a dependency in 9 of the 6,208 public GitHub projects set up for AI coding agents that we scanned, too few to describe it from them alone. Our scan also samples projects by dependency (Solana 2,661, Ethereum and EVM 1,496, 3D and games 2,818, agent frameworks and SDKs 10,983); counting those, it appears in 26 projects, and what it is used with below comes from all of them. Projects that use it most often also use Model Context Protocol SDK (JavaScript) (80.8%), Vitest (80.8%), Zod (88.5%).
TOON popularity over time
Gid Score 58: downloads 67, use in agent projects 31, GitHub stars 66, downloads trend 70 (each 0-100). How it is calculated.
Often used with TOON
| Model Context Protocol SDK (JavaScript) | 80.8% of TOON projects · 8.5× more than average |
|---|---|
| Vitest | 80.8% of TOON projects · 3.9× more than average |
| Zod | 88.5% of TOON projects · 3.5× more than average |
| tsx | 76.9% of TOON projects · 5.1× more than average |
| Commander | 73.1% of TOON projects · 26.4× more than average |
| jsonc-parser | 73.1% of TOON projects · 113.4× more than average |
| js-yaml | 69.2% of TOON projects · 32.1× more than average |
| Knip | 69.2% of TOON projects · 30.1× more than average |
From all 26 projects in our scan that use TOON, including the dependency samples.
By coding agent
| Claude Code | 0.3% of projects set up for it |
|---|---|
| GitHub Copilot | 0.2% of projects set up for it |
| Gemini CLI | 1.1% of projects set up for it |
Share of public repos configured for each agent that list TOON as a dependency.
Install
| Package | npm install @toon-format/toon |
|---|---|
| Main stacks | Next.js (17), TypeScript / JavaScript (9) |
| Example projects | diegosouzapw/OmniRoute, dyoshikawa/rulesync, ArgentAIOS/argentos-core, ai-integr8tor/diegosouzapw-OmniRoute, kunchenguid/agent-browser-axi |
Alternatives to TOON
In our scan, none of the most used tools in Prompts, structured output and evals does the same job as TOON: they are add-ons, companions or tools for a different task.
More in Prompts, structured output and evals: Ultracite tiktoken (Python) tokenizers LangSmith Langfuse (Python) GPT Tokenizer TokenLens @graphql-codegen/typescript-operations