lean-build

Define observable acceptance criteria and explicit non-goals before implementation, then stop when acceptance passes. This Skill enforces that workflow by deriving scope from the request and repository and omitting modes, providers, and polish unless acceptance requires them.

Trace the entry point through the layers that own invariants and deliver a coherent end-to-end path across them. Avoid forcing work into one file or a local patch, and refactor only when patching duplicates behavior or hides root causes.

Add surface area, dependencies, services, config, or migrations only when lifecycle design or acceptance criteria require them. When you do add one, state the material tradeoff explicitly so the cost is visible.

It is not suited for exploratory prototypes, greenfield architecture design, or work where broad extensibility is itself the requirement. It targets bounded feature slices in existing systems with identifiable acceptance criteria.

It reports only material omissions and the trigger that would require them, after running a focused proof that acceptance passes. The work is kept runnable and Core safety is preserved throughout.