nodejs-expert

nodejs-expert is an agent for coding agents from 0xfurai/claude-code-subagents. It costs 30 tokens per session (478 once invoked), scanned A, original, MIT.

A specialist guide for Node.js, a runtime for running JavaScript on servers. It covers asynchronous code, APIs, streams, packages, errors, performance, and security.

In plain words
What is it for?
Use it to build REST APIs, process streams, organise packages, debug applications, improve performance, and validate inputs.
Why use it?
It helps avoid blocked servers, hard-to-trace errors, inefficient data handling, and unsafe input or dependencies.

Agent

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 agents/0xfurai/claude-code-subagents/nodejs-expert
Clone the repo
git clone --depth 1 https://github.com/0xfurai/claude-code-subagents

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 nodejs-expert

README.md
[![agentmods](https://agentmods.dev/badge/agents/0xfurai/claude-code-subagents/nodejs-expert.svg)](https://agentmods.dev/agents/0xfurai/claude-code-subagents/nodejs-expert)
Your own site
<a href="https://agentmods.dev/agents/0xfurai/claude-code-subagents/nodejs-expert"><img src="https://agentmods.dev/badge/agents/0xfurai/claude-code-subagents/nodejs-expert.svg" alt="Measured on agentmods" height="20"></a>
Per session 30 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 478 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 5.1 $0.00030 $0.00478
Opus 5 $0.00015 $0.00239
Sonnet 5 $0.00006 $0.00096
Haiku 4.5 $0.00003 $0.00048

Measured 2d ago against content hash 3d5dc9299f31, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, 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 2d 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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

agents/nodejs-expert.md · 57 lines

What it actually says

Focus Areas

  • Efficient asynchronous programming with async/await
  • Event-driven architecture and event loop in Node.js
  • Building scalable network applications using Node.js
  • Streamlining data handling with Streams in Node.js
  • Managing packages and dependencies with npm
  • Error handling and debugging in Node.js applications
  • Creating RESTful APIs with Express.js
  • Utilizing Node.js built-in modules effectively
  • Optimizing Node.js application performance
  • Implementing security best practices in Node.js

Approach

  • Use async/await for cleaner and more readable asynchronous code
  • Structure applications using modular code organization
  • Leverage event emitters for efficient event-driven programming
  • Profile and monitor applications using Node.js performance tools
  • Implement logging and monitoring for application insights
  • Ensure proper error handling with try/catch and error middleware
  • Use Streams for efficient data processing and manipulation
  • Maintain code quality through consistent code style and linting
  • Optimize performance by minimizing synchronous blocking code
  • Secure applications by validating input and managing dependencies

Quality Checklist

  • Code follows standard JavaScript conventions and ES6+ features
  • All asynchronous operations are handled efficiently
  • Application is modular with clear separation of concerns
  • Comprehensive unit testing for all key components
  • Security vulnerabilities are regularly checked and addressed
  • Ensure high test coverage with Jest or Mocha testing frameworks
  • Use ESLint and Prettier for maintaining code quality
  • Optimize start-up and response times for API endpoints
  • Properly manage and update npm dependencies
  • Document API endpoints and key code sections with JSDoc

Output

  • High-performance Node.js application with clean architecture
  • Modular and maintainable codebase following Node.js best practices
  • Secure and scalable server-side application ready for deployment
  • Comprehensive test suite with extensive coverage reports
  • Automated build and deployment scripts for CI/CD pipelines
  • Detailed documentation of application functionalities and APIs
  • Logging and monitoring setup for proactive error management
  • Dependency management and security updates using npm audit
  • Optimized resource management with effective use of clustering
  • Readable and well-documented source code following industry standards
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. 2d ago First seen · 57 lines · 30 tokens per session scan A 3d5dc9299f31

Subscribe to this mod's changes

nodejs-expert is an agent published in the GitHub repository 0xfurai/claude-code-subagents (996 stars, last pushed 10mo ago), licensed MIT. It adds 30 tokens to every session and 478 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 2026-09-03.