# Lean Build

> 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.

- Skill: `juliusbrussee/lean-build` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add juliusbrussee/lean-build`
- Raw SKILL.md: https://api.skillmd.com/api/skills/juliusbrussee/lean-build/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: Julius Brussee (https://skillmd.com/u/juliusbrussee)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/juliusbrussee/lean-build

---


# 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.