Frontend Standards

Frontend Standards is a skill for Claude Code from systempromptio/systemprompt-template. It costs 22 tokens per session (2,619 once invoked), scanned A, original, no licence file.

A guide to frontend coding rules for JavaScript, CSS, accessibility, events, bundled files, and the administration interface. Accessibility means making an interface usable by people with different abilities and assistive technologies.

In plain words
What is it for?
Use it when creating or reviewing browser code, styles, event handling, build output, or admin screens.
Why use it?
It gives one set of rules for building frontend code that is consistent and usable.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the systemprompt-dev plugin — 10 skills, 6 agents shipped together

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 skills/systempromptio/systemprompt-template/dev-frontend-standards
Any agent
npx skills add systempromptio/systemprompt-template --skill dev-frontend-standards
Clone the repo
git clone --depth 1 https://github.com/systempromptio/systemprompt-template

Made for: Claude Code.

Or install systemprompt-dev, the plugin that ships this one along with the rest of its 10 skills, 6 agents.

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 Frontend Standards

README.md
[![agentmods](https://agentmods.dev/badge/skills/systempromptio/systemprompt-template/dev-frontend-standards.svg)](https://agentmods.dev/skills/systempromptio/systemprompt-template/dev-frontend-standards)
Your own site
<a href="https://agentmods.dev/skills/systempromptio/systemprompt-template/dev-frontend-standards"><img src="https://agentmods.dev/badge/skills/systempromptio/systemprompt-template/dev-frontend-standards.svg" alt="Measured on agentmods" height="20"></a>
Per session 22 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,619 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin unknown 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 $0.00022 $0.02619
Opus 5 $0.00011 $0.01309
Sonnet 5 $0.00004 $0.00524
Haiku 4.5 $0.00002 $0.00262

Measured 6d ago against content hash f4de0ed15b49, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

Frontend Standards 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 6d 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.

storage/files/plugins/systemprompt-dev/skills/dev-frontend-standards/SKILL.md · 302 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

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. 6d ago First seen · 302 lines · 22 tokens per session scan A f4de0ed15b49

Subscribe to this mod's changes

Frontend Standards is a skill published in the GitHub repository systempromptio/systemprompt-template (28 stars, last pushed yesterday), with no licence file. It adds 22 tokens to every session and 2,619 once invoked, about $0.0001 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.