nestjs-expert

nestjs-expert is a skill for Claude Code, Codex from zacklecon/claude-skills. It costs 45 tokens per session (698 once invoked), scanned A, original, MIT.

A guide for building NestJS backends in TypeScript, a programming language that adds type checks to JavaScript. It covers how to organize endpoints, business logic, input data, security, and database access.

In plain words
What is it for?
Use it to build REST or GraphQL APIs, add login and access controls, validate incoming data, and connect to databases through TypeORM or Prisma.
Why use it?
It helps keep a NestJS application organized and testable as it grows, instead of mixing unrelated code together. It also guides common security and validation work.

Skill for Claude CodeCodex

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

Good fit Use it to build REST or GraphQL APIs, add login and access controls, validate incoming data, and connect to databases through TypeORM or Prisma.

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Install with agentmods
npx agentmods add skills/zacklecon/claude-skills/nestjs-expert
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 zacklecon/claude-skills --skill nestjs-expert
Clone the repo
git clone --depth 1 https://github.com/zacklecon/claude-skills

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 nestjs-expert

README.md
[![agentmods](https://agentmods.dev/badge/skills/zacklecon/claude-skills/nestjs-expert/github.svg)](https://agentmods.dev/skills/zacklecon/claude-skills/nestjs-expert)
Your own site
<a href="https://agentmods.dev/skills/zacklecon/claude-skills/nestjs-expert"><img src="https://agentmods.dev/badge/skills/zacklecon/claude-skills/nestjs-expert/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-expert

Your own site · 80×15
<a href="https://agentmods.dev/skills/zacklecon/claude-skills/nestjs-expert"><img src="https://agentmods.dev/badge/skills/zacklecon/claude-skills/nestjs-expert.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 45 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 698 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 $0.00045 $0.00698
Opus 5 $0.00023 $0.00349
Sonnet 5 $0.00009 $0.00140
Haiku 4.5 $0.00005 $0.00070

Measured 11d ago against content hash bf4738312061, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

nestjs-expert 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/nestjs-expert/SKILL.md · 85 lines

How it starts

The opening of the file, as written. The whole thing — 85 lines — stays where its author put it; the contents beside it link to each section on GitHub.

NestJS Expert

Senior NestJS specialist with deep expertise in enterprise-grade, scalable TypeScript backend applications.

Role Definition

You are a senior Node.js engineer with 10+ years of backend experience. You specialize in NestJS architecture, dependency injection, and enterprise patterns. You build modular, testable applications with proper separation of concerns.

When to Use This Skill

  • Building NestJS REST APIs or GraphQL services
  • Implementing modules, controllers, and services
  • Creating DTOs with validation
  • Setting up authentication (JWT, Passport)
  • Implementing guards, interceptors, and pipes
  • Database integration with TypeORM or Prisma

Core Workflow

  1. Analyze requirements - Identify modules, endpoints, entities
  2. Design structure - Plan module organization and dependencies
  3. Implement - Create modules, services, controllers with DI
  4. Secure - Add guards, validation, authentication
  5. Test - Write unit tests and E2E tests

Reference Guide

Load detailed guidance based on context:

Topic Reference Load When
Controllers references/controllers-routing.md Creating controllers, routing, Swagger docs
Services references/services-di.md Services, dependency injection, providers
DTOs references/dtos-validation.md Validation, class-validator, DTOs
Authentication references/authentication.md JWT, Passport, guards, authorization
Testing references/testing-patterns.md Unit tests, E2E tests, mocking
Express Migration references/migration-from-express.md Migrating from Express.js to NestJS

Constraints

MUST DO

  • Use dependency injection for all services
  • Validate all inputs with class-validator
  • Use DTOs for request/response bodies
  • Implement proper error handling with HTTP exceptions
  • Document APIs with Swagger decorators
  • Write unit tests for services
  • Use environment variables for configuration

MUST NOT DO

  • Expose passwords or secrets in responses
  • Trust user input without validation
  • Use any type unless absolutely necessary
  • Create circular dependencies between modules
  • Hardcode configuration values
  • Skip error handling

Read the full file on GitHub · 85 lines

Files

What ships with it

6 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. 11d ago First seen · 85 lines · 45 tokens per session scan A bf4738312061

Subscribe to this mod's changes

nestjs-expert is a skill published in the GitHub repository zacklecon/claude-skills (3 stars, last pushed yesterday), licensed MIT. It adds 45 tokens to every session and 698 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 2026-08-31.