Lean Build

by JuliusBrussee

Lean Build is an AI Engineering skill for Claude Code, published by JuliusBrussee in caveman.

97.8K stars5.6K forkson JuliusBrussee/cavemanAdded 2026/08/13Repository updated 2026/08/13

View source on GitHub Download repo ZIP

aianthropiccavemanclaudeclaude-codellmmemeprompt-engineeringskilltokens

Install in seconds

Install Lean Build

Copy Lean Build into your Claude Code skills folder. Run the command in your terminal, or review the source on GitHub before installing.

terminal

npx degit https://github.com/JuliusBrussee/caveman/tree/main/skills/lean-build ~/.claude/skills/lean-build

Requires Node.js. Downloads this skill only — not the rest of the repository — into your Claude Code skills folder.

Without Node.js

git clone https://github.com/JuliusBrussee/caveman.git

Clones the whole repository, then copy the skill’s own directory into your skills folder yourself.

In this catalog

Source file: skills/lean-build/SKILL.md in JuliusBrussee/caveman
Installs to: ~/.claude/skills/lean-build
Collection: One of 20 skills cataloged from this repository
Category: AI Engineering — 2451 skills

What Lean Build does

Lean Build guides feature work with high overbuilding risk, enforcing repository reuse, strict scope, and an explicit stop condition. Use it for new behavior, product slices, or integrations where a minimal, complete path matters.

Lean Build is cataloged under AI Engineering on DirSkills. Lean Build comes from a repository tagged ai, anthropic, caveman, claude and claude-code.

Documentation

README

Excerpt

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.

This is the opening of the README. Read the full README on GitHub.

Frequently asked about Lean Build

What else does JuliusBrussee publish alongside Lean Build?
Lean Build is one of 20 skills that DirSkills catalogs from JuliusBrussee/caveman, the repository it ships in. Its siblings there include Cavecrew, Caveman and Caveman Commit. Each one is a separate skill with its own page in this directory, installs the same way Lean Build does, and is maintained by JuliusBrussee in that same repository. The rest of the collection is listed on the JuliusBrussee/caveman page.
How does Lean Build compare to other AI Engineering skills?
Lean Build ranks #38 by stars among the 2451 AI Engineering skills in this catalog. The most-starred ones next to it are Architecture Decision Records, AI-First Engineering and Agentic OS. DirSkills ranks by the star count of the repository each skill ships in, so that order reflects how popular those repositories are rather than any review of Lean Build against them. Open each page to compare what they document and how they install.