Argh is an opinionated derive-based argument parsing library for Rust, optimized for code size and conformance to Fuchsia CLI specifications. The repository is a multi-crate workspace: `argh` (public API, re-exports derive macros and provides runtime functions like `from_env`), `argh_derive` (proc-macro implementation of `FromArgs`, `FromArgValue`, and `ArgsInfo`), `argh_shared` (shared data structures for command metadata, used by both derive and completion crates), and `argh_complete` (generators for bash, zsh, fish, and nushell shell completions). The core architecture uses a derive macro to generate parsing code at compile time, producing minimal binary size. It supports switches, options (required, optional, repeating), positional arguments (including greedy/remainder), subcommands (static and dynamic), custom parsers via `FromArgValue`, default values, and extensive help/usage formatting with notes, examples, and error codes. The library is well-tested with unit tests, compile-fail UI tests, and integration tests. It is designed as a lightweight alternative to clap, prioritizing code size and compile-time speed.