AG Kit is a toolkit that gives Google Antigravity coding agents a structured workspace with rules, skills, specialist agents, workflows, persistent memory, orchestration, MCP guidance, and a safety hook. It is for building and operating agent workflows in Antigravity, and its catalogue entries provide parts of that workspace contract.
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.
npx agentmods add skills/vudovn/ag-kit/nodejs-best-practicesnpx skills add vudovn/ag-kit --skill nodejs-best-practicesgit clone --depth 1 https://github.com/vudovn/ag-kitWrote 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/vudovn/ag-kit/nodejs-best-practices)<a href="https://agentmods.dev/skills/vudovn/ag-kit/nodejs-best-practices"><img src="https://agentmods.dev/badge/skills/vudovn/ag-kit/nodejs-best-practices.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00033 | $0.02025 |
| Opus 5 | $0.00016 | $0.01012 |
| Sonnet 5 | $0.00007 | $0.00405 |
| Haiku 4.5 | $0.00003 | $0.00202 |
Grade A, and why
nodejs-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 4d 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.
Copies of this mod
8 near-identical copies found in the catalogue:
- nodejs-best-practices — 91% identical, 23 lines differ
- nodejs-best-practices — 91% identical, 23 lines differ
- nodejs-best-practices — 91% identical, 23 lines differ
- nodejs-best-practices — 91% identical, 23 lines differ
- nodejs-best-practices — 91% identical, 23 lines differ
- nodejs-best-practices — 89% identical, 24 lines differ
- nodejs-best-practices — 86% identical, 118 lines differ
- nodejs-best-practices — 86% identical, 33 lines differ
How it starts
The opening of the file, as written. The whole thing — 337 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Node.js Best Practices
Principles and decision-making for modern Node.js development. Learn to THINK, not memorize code patterns.
⚠️ How to Use This Skill
This skill teaches decision-making principles, not fixed code to copy.
- ASK user for preferences when unclear
- Choose framework/pattern based on CONTEXT
- Don't default to same solution every time
1. Framework Selection
Decision Tree
What are you building?
│
├── Edge/Serverless (Cloudflare, Vercel)
│ └── Hono (zero-dependency, ultra-fast cold starts)
│
├── High Performance API
│ └── Fastify (~5x req/sec of Express in Fastify's own hello-world benchmark; benchmark your own workload)
│
├── Enterprise/Team familiarity
│ └── NestJS (structured, DI, decorators)
│
├── Legacy/Stable/Maximum ecosystem
│ └── Express (mature, most middleware)
│
└── Full-stack with frontend
└── Next.js API Routes or tRPC
Comparison Principles
| Factor | Hono | Fastify | Express |
|---|---|---|---|
| Best for | Edge, serverless | Performance | Legacy, learning |
| Cold start | Fastest | Fast | Moderate |
| Ecosystem | Growing | Good | Largest |
| TypeScript | Native | Excellent | Good |
| Learning curve | Low | Medium | Low |
Selection Questions to Ask:
- What's the deployment target?
- Is cold start time critical?
- Does team have existing experience?
- Is there legacy code to maintain?
2. Runtime Considerations
Native TypeScript
Node.js 24+ (Active LTS): type-stripping ON by default
├── Run .ts files directly: node file.ts (no flag, stable since 24.12)
├── Erasable syntax only — enums, runtime namespaces, param properties error out
├── For those, use tsx (--experimental-transform-types was removed in Node 26)
└── Consider for: scripts, simple APIs
Module System Decision
ESM (import/export)
├── Modern standard
├── Better tree-shaking
├── Async module loading
└── Use for: new projects
CommonJS (require)
├── Legacy compatibility
├── More npm packages support
└── Use for: existing codebases, some edge cases
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.
- 4d ago First seen · 337 lines · 33 tokens per session scan A da0e84eb6dd2
nodejs-best-practices is a skill published in the GitHub repository vudovn/ag-kit (8,168 stars, last pushed 4d ago), licensed MIT. It adds 33 tokens to every session and 2,025 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 2026-08-30.
Other skills, from other repositories
systematic-debugging
Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.
brainstorming
You MUST use this before any creative work - creating features, building components, adding functionality, or modifying behavior. Explores user intent, requirements and design before implementation.
auto-perf-optimize
Run agent-driven VS Code performance or memory investigations. Use when asked to launch Code OSS, automate a VS Code scenario, run the Chat memory smoke runner, capture renderer heap snapshots, take workflow screenshots, compare run summaries, or drive a repeatable scenario before heap-snapshot analysis.
chat-perf
Run chat perf benchmarks and memory leak checks against the local dev build or any published VS Code version. Use when investigating chat rendering regressions, validating perf-sensitive changes to chat UI, or checking for memory leaks in the chat response pipeline.
chat-pet-sprite-creation
Use when creating or changing VS Code chat pet sprite art, sprite sheets, state animations, eye treatments, Stable/Insiders variants, or pet transitions under src/vs/workbench/contrib/chat/browser/widget/media/chatPet.
cpu-profile-analysis
Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating…