lean-build

lean-build is a skill for Claude Code, Codex from JuliusBrussee/caveman. It costs 36 tokens per session (208 once invoked), scanned A, original, no licence file.

A guide for building new features or integrations when there is a risk of adding more code or behavior than necessary.

In plain words
What is it for?
Use it for feature work, product changes, and integrations that need careful planning and an explicit definition of done.
Why use it?
It keeps implementation within a defined scope by encouraging reuse, limited changes, and a clear stopping point.

Skill for Claude CodeCodex

Written for Claude Code and Codex: shipped in a Claude Code plugin, but also agents/openai.yaml present.

Part of the caveman plugin — 20 skills, 7 commands, 3 agents shipped together

Good fit Use it for feature work, product changes, and integrations that need careful planning and an explicit definition of done.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/juliusbrussee/caveman/lean-build
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add JuliusBrussee/caveman --skill lean-build
Clone the repo
git clone --depth 1 https://github.com/JuliusBrussee/caveman

Made for: Claude Code, Codex.

Or install caveman, the plugin that ships this one along with the rest of its 20 skills, 7 commands, 3 agents.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for lean-build

README.md
[![agentmods](https://agentmods.dev/badge/skills/juliusbrussee/caveman/lean-build.svg)](https://agentmods.dev/skills/juliusbrussee/caveman/lean-build)
Your own site
<a href="https://agentmods.dev/skills/juliusbrussee/caveman/lean-build"><img src="https://agentmods.dev/badge/skills/juliusbrussee/caveman/lean-build.svg" alt="Measured on agentmods" height="20"></a>
Per session 36 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 208 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • Socket pass 17 Aug 2026
  • Snyk pass 17 Aug 2026
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin unknown No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00036 $0.00208
Opus 5 $0.00018 $0.00104
Sonnet 5 $0.00007 $0.00042
Haiku 4.5 $0.00004 $0.00021

Measured 8d ago against content hash 4d498073c631, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

lean-build scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/lean-build/SKILL.md · 19 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 19 lines · 36 tokens per session scan A 4d498073c631

Subscribe to this mod's changes

lean-build is a skill published in the GitHub repository JuliusBrussee/caveman (103,979 stars, last pushed yesterday), with no licence file. It adds 36 tokens to every session and 208 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.