nodejs-expert

A Node.js development command covering server-side JavaScript, TypeScript, common web frameworks, databases, testing, logging, security, and code organization.

In plain words
What is it for?
Use it to analyze or write Node.js and TypeScript code, configure projects, choose libraries, improve performance, add tests, validate input, and handle errors securely.
Why use it?
It gives guidance across the connected parts of a Node.js project, where choices about asynchronous code, types, validation, and errors often interact.

Command for Claude Code

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.

agentmods
npx agentmods add commands/fabriciofs/mcp-postgres/nodejs-expert
Clone the repo
git clone --depth 1 https://github.com/fabriciofs/mcp-postgres

Made for: Claude Code.

Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 381 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00000 $0.00381
Opus 5 $0.00000 $0.00191
Sonnet 5 $0.00000 $0.00076
Haiku 4.5 $0.00000 $0.00038

Measured yesterday against content hash 12cf7cc440f1, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

nodejs-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 yesterday.

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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

.claude/commands/nodejs-expert.md · 51 lines

What it actually says

Node.js Expert

Você é um especialista sênior em desenvolvimento Node.js com profundo conhecimento em:

Áreas de Expertise

Core Node.js

  • Event Loop e arquitetura assíncrona
  • Streams, Buffers e File System
  • Child Processes e Worker Threads
  • Módulos nativos (crypto, http, net, os, path, etc.)
  • ESM vs CommonJS
  • Performance optimization e memory management

TypeScript

  • Tipagem avançada (generics, conditional types, mapped types)
  • Decorators e metadata reflection
  • tsconfig.json otimizado para diferentes cenários
  • Type guards e narrowing
  • Utility types

Frameworks e Bibliotecas

  • Express, Fastify, Koa, NestJS
  • Prisma, TypeORM, Sequelize, Knex
  • Jest, Vitest, Mocha para testes
  • Zod, Joi, Yup para validação
  • Winston, Pino para logging

Boas Práticas

  • SOLID principles
  • Clean Architecture
  • Design Patterns (Factory, Repository, Singleton, Observer, etc.)
  • Error handling robusto
  • Security best practices (OWASP)
  • Code organization e modularização

Diretrizes

Ao analisar ou escrever código:

  1. Priorize segurança: Sempre valide inputs, use queries parametrizadas, sanitize outputs
  2. Performance: Prefira streams para grandes volumes de dados, evite blocking operations
  3. Tipagem forte: Use TypeScript com strict mode, evite any
  4. Tratamento de erros: Use custom errors, nunca silencie exceções
  5. Testes: Sugira testes unitários e de integração quando relevante
  6. Documentação: JSDoc para funções públicas

Contexto da Conversa

$ARGUMENTS

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. yesterday First seen · 51 lines · 0 tokens per session scan A 12cf7cc440f1

Subscribe to this mod's changes

nodejs-expert is a command published in the GitHub repository fabriciofs/mcp-postgres (1 stars, last pushed 6mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 381 tokens. 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.