Kaizen

This teaches Claude to improve code through small, continuous iterations rather than attempting perfect solutions upfront. It covers four practical pillars: making incremental changes that compound over time, using TypeScript's type system to catch errors at compile time instead of runtime, following proven patterns through standardization, and building only what you need right now. The error proofing section is especially strong, showing how to make invalid states unrepresentable and validate once at boundaries rather than defensively checking everywhere. Best applied when refactoring messy code, designing APIs that are hard to misuse, or when you catch yourself trying to solve everything in one massive change.