nestjs-security

nestjs-security is a skill for Claude Code from dkmqflx/nestjs-best-practices-plugin. It costs 59 tokens per session (527 once invoked), scanned A, original, MIT.

Guidance for hardening NestJS services against common web risks, including unsafe headers, excessive requests, broad browser access, leaked secrets, unwanted input, and oversized payloads.

In plain words
What is it for?
Use it when preparing production services, reviewing security, configuring Helmet, rate limits, CORS, CSRF protection, input validation, secret storage, or request-size limits.
Why use it?
It helps close security gaps that NestJS does not configure automatically, especially before exposing an API publicly.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the nestjs-best-practices plugin — 12 skills shipped together

Good fit Use it when preparing production services, reviewing security, configuring Helmet, rate limits, CORS, CSRF protection, input validation, secret storage, or request-size limits.

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

Made for: Claude Code.

Or install nestjs-best-practices, the plugin that ships this one along with the rest of its 12 skills.

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 nestjs-security

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/dkmqflx/nestjs-best-practices-plugin/nestjs-security"><img src="https://agentmods.dev/badge/skills/dkmqflx/nestjs-best-practices-plugin/nestjs-security.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 59 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 527 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.
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 $0.00059 $0.00527
Opus 5 $0.00030 $0.00264
Sonnet 5 $0.00012 $0.00105
Haiku 4.5 $0.00006 $0.00053

Measured 9d ago against content hash 56558d2e9896, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

nestjs-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 9d 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.

plugins/nestjs-best-practices/skills/nestjs-security/SKILL.md · 36 lines

What it actually says

NestJS Security

Hardening rules for production NestJS apps (v10/v11). These cover the gaps the framework leaves open by default — headers, rate limiting, CORS, secrets, and input validation — for both the Express and Fastify platforms.

When to Apply

  • Preparing a NestJS service for production or running a security review.
  • Exposing an API to the public internet or to browser clients.
  • Adding security headers (helmet), rate limiting (ThrottlerModule), or CORS (enableCors).
  • Handling auth: cookie-based sessions, CSRF, or password storage.
  • Mitigating DoS via payload-size limits.

Rules

How to Use

Read the rule whose topic matches the change you are making, then apply the Correct pattern. When doing a full production review, walk every rule top to bottom as a checklist. Each rule notes Express vs Fastify differences where they matter — confirm which platform adapter the app uses before copying code.

Files

What ships with it

8 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.

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. 9d ago First seen · 36 lines · 59 tokens per session scan A 56558d2e9896

Subscribe to this mod's changes

nestjs-security is a skill published in the GitHub repository dkmqflx/nestjs-best-practices-plugin (1 stars, last pushed 2mo ago), licensed MIT. It adds 59 tokens to every session and 527 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 2026-08-31.

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