Borrowing it
Nothing to install: this file belongs to susomejias/rembric. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/susomejias/rembric/main/.agents/skills/npm-security-best-practices/SKILL.mdgit clone --depth 1 https://github.com/susomejias/rembricWrote 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/susomejias/rembric/npm-security-best-practices)<a href="https://agentmods.dev/skills/susomejias/rembric/npm-security-best-practices"><img src="https://agentmods.dev/badge/skills/susomejias/rembric/npm-security-best-practices/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/susomejias/rembric/npm-security-best-practices"><img src="https://agentmods.dev/badge/skills/susomejias/rembric/npm-security-best-practices.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 11 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 3 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 20 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 22 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 61 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 343 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 358 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 Rogue Agent · line 101 Skill modifies its own code, configuration, or behavior at runtime. Self-modification enables an agent to escalate privileges, disable safety constraints, or install persistent backdoors.Fix: Prevent the skill from modifying its own code, SKILL.md, or configuration files. Treat skill files as read-only at runtime.
- high Privilege Escalation · line 183 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 189 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 107 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]
- medium MCP Rug Pull · line 146 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]
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 | $0.00059 | $0.03886 |
| Opus 5 | $0.00030 | $0.01943 |
| Sonnet 5 | $0.00012 | $0.00777 |
| Haiku 4.5 | $0.00006 | $0.00389 |
Grade A, and why
npm-security-best-practices 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 — 380 lines — stays where its author put it; the contents beside it link to each section on GitHub.
npm Security Best Practices
A general reference for hardening any npm-ecosystem project (npm, pnpm, yarn, bun) against supply-chain attacks. Adapted from lirantal/npm-security-best-practices. Use this skill whenever you are about to add a dependency, edit install-time configuration, review a lockfile diff, or configure CI install steps.
For the project-specific snapshot date, upstream commit SHA, and quarterly re-read reminder, see references/source.md. For a one-page scan-friendly summary, see references/checklist.md. For ready-to-paste configs, see references/pnpm-config.md and references/ci-snippets.md.
1. Disable post-install scripts
Lifecycle scripts (preinstall, install, postinstall, dependency-side prepare) run during npm install against every transitive dep. Compromised packages exfiltrate secrets or install malware from these hooks. The default-deny stance: block all of them, then allowlist exceptions.
How to apply
npm / pnpm (≤ 9): set ignore-scripts=true in .npmrc. Per-install override: npm install --ignore-scripts.
pnpm 10.x: combine .npmrc::ignore-scripts=true with pnpm-workspace.yaml::onlyBuiltDependencies: [pkg1, pkg2] for an auditable allowlist.
pnpm 11+: the legacy onlyBuiltDependencies list is replaced by an explicit pnpm-workspace.yaml::allowBuilds: map with per-package booleans. Lifecycle scripts that aren't listed default to denied; false is allowed for explicit-deny documentation. Native bindings (better-sqlite3, sharp, etc.) and tools that need git-hook setup (husky) typically go here:
allowBuilds:
husky: true
better-sqlite3: true
esbuild: false # explicit deny, documents the choice
bun: scripts are disabled by default. Allowlist via trustedDependencies in package.json.
yarn (v2+): native bindings work via PnP / Plug'n'Play; for v1 use --ignore-scripts.
What ships with it
4 files 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.
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 · 380 lines · 59 tokens per session scan A 3c8763e8b663
npm-security-best-practices is a skill published in the GitHub repository susomejias/rembric (12 stars, last pushed 9d ago), licensed MIT. It adds 59 tokens to every session and 3,886 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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