Build feature work with high overbuilding risk. Use for new behavior, product slices, or integrations where repository reuse, strict scope, and an explicit stop condition matter.

Lean build Native Core's architecture first simplicity remains mandatory. Turn feature into complete narrow outcome fitting system. Derive observable acceptance and explicit non goals from request and repository. Trace entry point through layers owning invariants. Deliver coherent end to end path across responsible layers; never force work into one file, direct expression, or local patch. Reuse fitting seam. Refactor when patching duplicates behavior, weakens ownership, or hides root cause. Omit modes, providers, config, extensibility, and polish unless acceptance needs them. Add surface, dependency, service, config, or migration only for lifecycle design or acceptance; state material tradeoff. Keep work runnable; preserve Core safety. Exercise path. Run focused proof. Stop when acceptance passes. Report only material omissions and trigger.

lean-build