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.
npx skills add AratKruglik/claude-sdlc --skill npm-patternsgit clone --depth 1 https://github.com/AratKruglik/claude-sdlcWrote 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.
[](https://agentmods.dev/skills/aratkruglik/claude-sdlc/npm-patterns)<a href="https://agentmods.dev/skills/aratkruglik/claude-sdlc/npm-patterns"><img src="https://agentmods.dev/badge/skills/aratkruglik/claude-sdlc/npm-patterns/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/aratkruglik/claude-sdlc/npm-patterns"><img src="https://agentmods.dev/badge/skills/aratkruglik/claude-sdlc/npm-patterns.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00147 | $0.01974 |
| Opus 5 | $0.00073 | $0.00987 |
| Sonnet 5 | $0.00029 | $0.00395 |
| Haiku 4.5 | $0.00015 | $0.00197 |
Grade A, and why
npm-patterns 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 12d 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.
How it starts
The opening of the file, as written. The whole thing — 165 lines — stays where its author put it; the contents beside it link to each section on GitHub.
npm / yarn / pnpm Patterns (stack-agnostic)
This skill consolidates package management idioms applicable to any JS/TS project — backend, frontend, mobile, library. Apply when modifying package.json, adding dependencies, or defining scripts.
Detect the package manager
Look at the lockfile in the project root:
| Lockfile present | Use |
|---|---|
package-lock.json |
npm |
yarn.lock |
yarn |
pnpm-lock.yaml |
pnpm |
bun.lockb / bun.lock |
bun (rare; mostly drop-in for npm) |
| (none) | npm — but flag in DECISIONS that no lockfile is committed |
Also check package.json "packageManager" field (e.g. "packageManager": "[email protected]") — when present, it overrides lockfile inference.
Map common commands:
| Action | npm | yarn | pnpm |
|---|---|---|---|
| Install all | npm install |
yarn install |
pnpm install |
| Add runtime dep | npm install pkg |
yarn add pkg |
pnpm add pkg |
| Add dev dep | npm install -D pkg |
yarn add -D pkg |
pnpm add -D pkg |
| Run script | npm run x |
yarn x |
pnpm x |
| Update lockfile | npm install |
yarn install |
pnpm install |
Always run the install command after editing package.json — never edit the lockfile by hand.
Dependency fields
| Field | Use for |
|---|---|
dependencies |
Runtime — what the production app needs to run (express, react, pinia, axios). |
devDependencies |
Dev tooling — bundlers, test runners, linters, type definitions, dev servers. |
peerDependencies |
Library authors only — declares what host app must provide (e.g., react for a React component library). |
optionalDependencies |
Rare — install failure should not break install (native binaries with fallbacks). |
bundledDependencies |
Rare — packaged inside npm pack tarball. |
Rule of thumb: if the code is bundled into the production output for runtime use, it's a dependency. If it only runs during npm test / npm run build / lint, it's a devDependency.
Frontend nuance: bundlers (Vite/Webpack/esbuild) often tree-shake unused exports — but the package still belongs in dependencies if any production-rendered code imports it.
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.
- 12d ago First seen · 165 lines · 147 tokens per session scan A a137af6c135f
npm-patterns is a skill published in the GitHub repository AratKruglik/claude-sdlc (33 stars, last pushed 7d ago), licensed MIT. It adds 147 tokens to every session and 1,974 once invoked, about $0.0007 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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