npm-security

npm-security is a skill for Claude Code, Codex from bodadotsh/npm-security-best-practices. It costs 43 tokens per session (818 once invoked), scanned A, original, MIT.

Security guidance for JavaScript and TypeScript projects that use package managers such as npm, pnpm, Yarn, Bun, or Deno.

In plain words
What is it for?
Use it when planning, installing, or updating packages, or when configuring a package manager.
Why use it?
It reduces the risk of installing compromised packages or running unwanted installation code. It also helps avoid silently changing package versions without the developer's knowledge.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it when planning, installing, or updating packages, or when configuring a package manager.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/bodadotsh/npm-security-best-practices/npm-security
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 bodadotsh/npm-security-best-practices --skill npm-security
Clone the repo
git clone --depth 1 https://github.com/bodadotsh/npm-security-best-practices

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 npm-security

README.md
[![agentmods](https://agentmods.dev/badge/skills/bodadotsh/npm-security-best-practices/npm-security/github.svg)](https://agentmods.dev/skills/bodadotsh/npm-security-best-practices/npm-security)
Your own site
<a href="https://agentmods.dev/skills/bodadotsh/npm-security-best-practices/npm-security"><img src="https://agentmods.dev/badge/skills/bodadotsh/npm-security-best-practices/npm-security/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.

agentmods 80×15 button for npm-security

Your own site · 80×15
<a href="https://agentmods.dev/skills/bodadotsh/npm-security-best-practices/npm-security"><img src="https://agentmods.dev/badge/skills/bodadotsh/npm-security-best-practices/npm-security.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 43 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 818 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
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 5 findings, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Privilege Escalation · line 18
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
  • high Privilege Escalation · line 24
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
  • high Privilege Escalation · line 30
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
  • high Privilege Escalation · line 32
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
  • medium MCP Rug Pull · line 67
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
How audits are shown
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 5.1 $0.00043 $0.00818
Opus 5 $0.00022 $0.00409
Sonnet 5 $0.00009 $0.00164
Haiku 4.5 $0.00004 $0.00082

Measured 11d ago against content hash 23529ab30adb, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

npm-security 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 11d 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/npm-security/SKILL.md · 86 lines

How it starts

The opening of the file, as written. The whole thing — 86 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Apply the following security best practices. Never override an explicit user opt-in config (lifecycle scripts, cooldowns, save prefix, etc) unless they ask.

Always check current package manager's verions, and verify against their official documentations. See "References" for links or perfom web searches.

Environment defaults

For the following best practices, we are using npm as example but you should check to see which package manager is available and apply the configurations according.

Lifecycle scripts

Unless explicitly defined otherwiese, package managers should have lifecycle scripts set as off, for example preinstall and postinstall.

In .npmrc, this can be set as ignore-scripts=true, or through install command: npm install --ignore-scripts <package>.

Cooldowns / minimum release age

Unless explicitly defined otherwiese, package installations should respect a cooldown period (default to 1 day).

In .npmrc, this can be set as min-release-age=1, or through install command npm install --min-release-age=1 <package>.

Exact versions

Unless explicitly defined otherwise, package installations should install the expact version instead of a semver range.

In .npmrc, this can be set as save-exact=true, or through install command npm install --save-exact <package>

Persist these defaults in the project .npmrc (or the package manager’s equivalent), merging only keys that are unset; never overwrite existing values unless the user asks.

Planning stage / package scorer

When planning third-party dependencies, we should score package candidates first. This reduces risk of using greyware (dependencies are not exactly malware, but can be trollware, abandonware, low quality, etc).

A free scorer solution is the Socket MCP server. Can use other package scorers if user configured explicitly.

An example Socket MCP server can be figured as:

{
  "mcpServers": {
    "socket-mcp": {
      "type": "http",
      "url": "https://mcp.socket.dev/"
    }
  }
}

Read the full file on GitHub · 86 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. 11d ago First seen · 86 lines · 43 tokens per session scan A 23529ab30adb

Subscribe to this mod's changes

npm-security is a skill published in the GitHub repository bodadotsh/npm-security-best-practices (858 stars, last pushed 17d ago), licensed MIT. It adds 43 tokens to every session and 818 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.

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