Rust Coding Skill

Opinionated Rust rules for the Copilot Rust SDK (rust/). Priority order:

1. Readable code — every line should earn its place
2. Correct code — especially in concurrent/async contexts
3. Performant code — think about allocations, data structures, hot paths

Error handling

The SDK's public error type is crate::Error (rust/src/errors.rs). Add new variants to crate::ErrorKind rather than introducing parallel error enums per module — every public failure mode is part of the API contract and should be expressible in one type.

anyhow is reserved for binaries and example code. Library code never returns anyhow::Result — callers can't pattern-match on anyhow::Error, so it would prevent them from handling specific failures.