It also covers the recoverable-errors-vs-panics decision — Result for anything a caller could reasonably recover from, panic!/unwrap/expect reserved for broken invariants — and the rule that anyhow::Error must never leak into a library's public API.

Out of scope: general ownership/borrowing design belongs to rust-core-language; async-runtime-specific error handling is not covered here.

Rust Error Handling

The consensus split: thiserror for libraries, anyhow for applications. A library exposes a typed error its callers can match; an application wants one ergonomic error type and rich context. Getting this boundary right is the whole discipline.