SNAFU is a Rust library for ergonomic error handling. It provides a `#[derive(Snafu)]` proc-macro that generates custom error types with automatic 'context selectors' (e.g., `ReadConfigSnafu`) and implements standard traits (`Display`, `Error`, `From`). The library also offers extension traits (`ResultExt`, `OptionExt`, `TryFutureExt`, `TryStreamExt`) to attach contextual information to underlying errors, macros (`ensure!`, `whatever!`) for concise error creation, and a `Report` type for user-facing error output. It supports `no_std` environments (with `alloc`) and includes backtrace capture, location tracking, and an unstable provider API for attaching arbitrary data to errors. The crate is mature and widely adopted, but contains some deprecated features (e.g., `backtraces-impl-backtrace-crate`) and a complex feature-flag matrix. The companion `snafu-derive` crate handles all proc-macro generation, and the architecture cleanly separates parsing, validation, and code generation.