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 skills add HoangNguyen0403/agent-skills-standard --skill best-practicesgit clone --depth 1 https://github.com/HoangNguyen0403/agent-skills-standardWrote 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/hoangnguyen0403/agent-skills-standard/best-practices)<a href="https://agentmods.dev/skills/hoangnguyen0403/agent-skills-standard/best-practices"><img src="https://agentmods.dev/badge/skills/hoangnguyen0403/agent-skills-standard/best-practices/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.
<a href="https://agentmods.dev/skills/hoangnguyen0403/agent-skills-standard/best-practices"><img src="https://agentmods.dev/badge/skills/hoangnguyen0403/agent-skills-standard/best-practices.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 5.1 | $0.00017 | $0.00423 |
| Opus 5.5 | $0.00007 | $0.00169 |
| Sonnet 5.5 | $0.00003 | $0.00085 |
| Haiku 4.5 | $0.00002 | $0.00042 |
Grade A, and why
JavaScript Best Practices scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
What it actually says
JavaScript Best Practices
Priority: P1 (OPERATIONAL)
Conventions and patterns for writing maintainable JavaScript.
Implementation Guidelines
- Naming:
camelCase(vars/funcs),PascalCase(classes),UPPER_SNAKE(constants). - Errors: Throw
Errorobjects only. Handle all async errors. - Comments: JSDoc for APIs. Explain "why" not "what".
- Files: One entity per file.
index.jsfor exports. - Modules: Named exports only. Order: Ext -> Int -> Rel.
Anti-Patterns
- No Globals: Encapsulate state.
- No Magic Numbers: Use
const. - No Nesting: Guard clauses/early returns.
- No Defaults: Use named exports.
- No Side Effects: Keep functions pure.
Code
// Constants
const STATUS = { OK: 200, ERROR: 500 };
// Errors
class APIError extends Error {
constructor(msg, code) {
super(msg);
this.code = code;
}
}
// Async + JDoc
/** @throws {APIError} */
export async function getData(id) {
if (!id) throw new APIError('Missing ID', 400);
const res = await fetch(`/api/${id}`);
if (!res.ok) throw new APIError('Failed', res.status);
return res.json();
}
Reference & Examples
For module patterns and project structure: See references/REFERENCE.md.
Related Topics
language | tooling
What ships with it
1 file 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.
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.
- 1mo ago First seen · 65 lines · 17 tokens per session scan A 990a75fe88c6
JavaScript Best Practices is a skill published in the GitHub repository HoangNguyen0403/agent-skills-standard (583 stars, last pushed today), licensed MIT. It adds 17 tokens to every session and 423 once invoked, about $0.0001 per session on Opus 5.5. 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.
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