engineering

engineering is a skill for Claude Code, Codex from wellwelwel/lagune. It costs 51 tokens per session (1,504 once invoked), scanned A, original, MIT.

Engineering instructions for Lagune, a TypeScript command-line tool. They cover its runtimes, code rules, build and distribution process, tests, and change-tracking hooks.

In plain words
What is it for?
For developing, testing, building, and distributing Lagune code, including its TypeScript source, ES module setup, runtime-specific tests, and deterministic tracking hooks.
Why use it?
They help contributors make source changes that work across Node.js, Bun, and Deno and follow the project’s type-checking and testing process.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/wellwelwel/lagune/engineering
Any agent
npx skills add wellwelwel/lagune --skill engineering
Clone the repo
git clone --depth 1 https://github.com/wellwelwel/lagune

Made for: Claude Code, Codex.

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 engineering

README.md
[![agentmods](https://agentmods.dev/badge/skills/wellwelwel/lagune/engineering.svg)](https://agentmods.dev/skills/wellwelwel/lagune/engineering)
Your own site
<a href="https://agentmods.dev/skills/wellwelwel/lagune/engineering"><img src="https://agentmods.dev/badge/skills/wellwelwel/lagune/engineering.svg" alt="Measured on agentmods" height="20"></a>
Per session 51 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,504 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original 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 $0.00051 $0.01504
Opus 5 $0.00026 $0.00752
Sonnet 5 $0.00010 $0.00301
Haiku 4.5 $0.00005 $0.00150

Measured 5d ago against content hash 8b2fc7ff8bf8, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

engineering 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 5d 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.

.claude/skills/engineering/SKILL.md · 61 lines

How it starts

The opening of the file, as written. The whole thing — 61 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Lagune engineering

This skill is the specialized, authoritative description of how Lagune is built: the toolchain, code conventions, type rules, the build and distribution path, and the implementation of the deterministic tracking hooks. Consult it before writing or changing source, before touching the build, and whenever you apply the code conventions.

The product mission and workflow philosophy live in CLAUDE.md. The repository layout, the command/template split, the core/adapter boundary, what Lagune scaffolds, and the tracking-map model live in the architecture skill. This skill covers the build, not the shape.

Toolchain

  • Runtimes: Node.js (current LTS), Bun, and Deno. Lagune must run on all three, so keep code runtime-agnostic.
  • Language: TypeScript, authored in src/.
  • Module system: ES Modules only (ESM) throughout.
  • Package manager: npm, matching the npx/npm distribution path.
  • Bundler: esbuild (transpile and bundle only, it does not type-check).
  • Type-checking: tsc --noEmit, run separately since esbuild skips type checks.
  • Tests: Poku, run against each runtime: Node (npm test), Bun (bun run test:bun), and Deno (deno task test:deno).

Code conventions

General

  • Arrow functions over function. Declare with const. Use a function only when the this context strictly requires it.
  • Named exports only. Never use default export.
  • Practice early return. Handle edge cases up front and exit, rather than nesting the main logic.
  • No abbreviations. Names are clear and explicit (for example left/right, not a/b, and index, not i).
  • Avoid nested if-else-else-if. Favor clean, well-decoupled approaches when branching grows.
  • No duplicated logic or types. Reuse existing logic and types whenever it is viable.
  • No side effects inside loops or iterations. Keep iteration pure.
  • Prefer native capabilities over external dependencies whenever possible.
  • Always prefix native imports with node: (for example node:path, node:fs).
  • Prefer the async Node.js APIs when viable (for example node:fs/promises).

Read the full file on GitHub · 61 lines

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. 5d ago First seen · 61 lines · 51 tokens per session scan A 8b2fc7ff8bf8

Subscribe to this mod's changes

engineering is a skill published in the GitHub repository wellwelwel/lagune (140 stars, last pushed 5d ago), licensed MIT. It adds 51 tokens to every session and 1,504 once invoked, about $0.0003 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.

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