This is a focused collection of Rust patterns for RTK's CLI filter architecture. It covers seven patterns with real examples: Newtype for type safety (preventing token count mixups), Builder for complex configs, State Machine for parsing multi-section output like pytest results, and others. The guide includes an honest anti-patterns section that pushes back against over-engineering, like adding async traits for "future-proofing" in a deliberately single-threaded tool. The pattern selection table is genuinely useful for deciding when to use what. Use this when you're adding a new filter module or refactoring existing ones and want to avoid both primitive obsession and unnecessary abstraction.
npx skills add https://github.com/rtk-ai/rtk --skill design-patterns