TOON (Token-Oriented Object Notation) is a human-readable serialization format designed to minimize LLM token usage while preserving lossless round-trip conversion with JSON. This monorepo provides the reference TypeScript implementation (`@toon-format/toon`) and a CLI tool (`@toon-format/cli`) for encoding/decoding TOON. The library features streaming encode/decode, tabular forms for uniform data, normalization of special JavaScript values (BigInt, Date, Set, Map), security hardening against prototype pollution, and a replacer function with path tracking. The CLI supports stdin/stdout conversion, auto-detection by file extension, token statistics, and delimiter options. The repository also includes an extensive benchmark suite comparing TOON against JSON, YAML, XML, and CSV across token efficiency and retrieval accuracy using multiple LLMs (Claude, Gemini, GPT, Grok). Results show TOON matches JSON's accuracy while using ~43% fewer tokens. A documentation site with an interactive playground is provided via VitePress. The codebase is well-structured with clean abstractions, streaming APIs, and thorough testing, though it relies on an external spec repository and has a single author, creating bus factor risk.