A set of coding guidance for building, reviewing, and optimizing frontend interfaces. It covers React, forms, routing, data fetching, accessibility, styling, motion, and interface design.

Use it when creating or refining web interfaces, React components, forms, navigation, accessibility, performance, or visual design.

It brings related frontend practices together so interface work can be reviewed and improved consistently.

frontend — Plugin for Claude Code by fellipeutaka/leon

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.

Clone the repo

git clone --depth 1 https://github.com/fellipeutaka/leon

Made for: Claude Code.

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.

README.md

[![agentmods](https://agentmods.dev/badge/plugins/fellipeutaka/leon/frontend/github.svg)](https://agentmods.dev/plugins/fellipeutaka/leon/frontend)

Your own site

<a href="https://agentmods.dev/plugins/fellipeutaka/leon/frontend"><img src="https://agentmods.dev/badge/plugins/fellipeutaka/leon/frontend/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.

Your own site · 80×15

<a href="https://agentmods.dev/plugins/fellipeutaka/leon/frontend"><img src="https://agentmods.dev/badge/plugins/fellipeutaka/leon/frontend.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session not measured What this adds to a session before it is invoked.

When invoked not measured The manifest loads nothing itself; its 35 skills cost 2,722 tokens a session between them.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Security

Grade A, and why

frontend 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.

.claude-plugin/marketplace.json#frontend · 43 lines

What it actually says

{
  "name": "frontend",
  "description": "Skills for building, reviewing, and optimizing frontend interfaces.",
  "source": "./",
  "strict": false,
  "skills": [
    "./skills/ai-sdk",
    "./skills/baseline-ui",
    "./skills/canvas-design",
    "./skills/composition-patterns",
    "./skills/denji",
    "./skills/design-lab",
    "./skills/fixing-accessibility",
    "./skills/fixing-metadata",
    "./skills/fixing-motion-performance",
    "./skills/frontend-design",
    "./skills/figma-raw-geometry",
    "./skills/interface-design",
    "./skills/interaction-design",
    "./skills/kanpeki",
    "./skills/motion",
    "./skills/nuqs",
    "./skills/paraglide-js",
    "./skills/react-best-practices",
    "./skills/react-hook-form-zod",
    "./skills/react-native-skills",
    "./skills/shadcn",
    "./skills/shadcn-dream",
    "./skills/tanstack-ai",
    "./skills/tanstack-db",
    "./skills/tanstack-form",
    "./skills/tanstack-hotkeys",
    "./skills/tanstack-query",
    "./skills/tanstack-react-store",
    "./skills/tanstack-router",
    "./skills/tanstack-virtual",
    "./skills/tanstack-pacer",
    "./skills/tanstack-table",
    "./skills/ui-ux-pro-max",
    "./skills/web-design-guidelines",
    "./skills/zustand"
  ]
}

Contents

What it installs

The manifest is a name and a version. 35 skills travel with it, and installing the plugin installs all of them — 2,722 tokens a session between them. Each is measured on its own page, and each can be installed alone.

Files

What ships with it

1 file beside marketplace.json#frontend 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.

marketplace.json 4.4 KB

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.

yesterday First seen · 43 lines scan A 2b84b4f072e0

Subscribe to this mod's changes

frontend is a plugin published in the GitHub repository fellipeutaka/leon (5 stars, last pushed yesterday), licensed MIT. Its token cost is not measured: this kind of file is read by the harness, not the model. 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 2026-11-05.

CSS and styling Design and UX Frontend React

frontend next to 6 plugins from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
frontendfellipeutaka/leon	Plugin	5	yesterday	MIT	A	—	Claude Code
shadcnshadcn-ui/ui	Plugin	127k	yesterday	MIT	A	—	Cursor
frontendjezweb/claude-skills	Plugin	1.1k	28d ago	MIT	A	—	Claude Code
ui-polishopkod-france/opkod-claude-code-plugins	Plugin	10	1mo ago	MIT	A	—	Claude Code
frontend-developerarmanzeroeight/fastagent-plugins	Plugin	29	3mo ago	MIT	A	—	Claude Code
uiforgeTaewoooPark/UIForge	Plugin	10	3mo ago	MIT	A	—	Claude Code
ui-ux-design-proca-who-codes/ultimate.UIUX.design.skills	Plugin	6	3mo ago	MIT	A	—	Claude Code