frontend-developer

frontend-developer is a skill for Claude Code, Codex from rmyndharis/antigravity-skills. It costs 55 tokens per session (1,469 once invoked), scanned A, original, MIT.

A frontend development guide for building React and Next.js interfaces, including components, responsive layouts, browser-side state, accessibility, and performance.

In plain words
What is it for?
Use it to create or fix React and Next.js pages, components, data-fetching flows, responsive behavior, and frontend performance issues.
Why use it?
It helps organize user-interface work and address common problems such as slow pages, inaccessible controls, and difficult-to-maintain state.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

About the project

Antigravity Skill Vault is a collection of reusable Agent Skills for Google Antigravity, covering software development, operations, security, and business work. It is for people who want Antigravity agents to follow specialized expertise, personas, and structured workflows. The catalogue skills are entries from this collection.

rmyndharis/antigravity-skills · 1,480 stars · on GitHub

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/rmyndharis/antigravity-skills/frontend-developer
Any agent
npx skills add rmyndharis/antigravity-skills --skill frontend-developer
Clone the repo
git clone --depth 1 https://github.com/rmyndharis/antigravity-skills

Made for: Claude Code, Codex.

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-developer

README.md
[![agentmods](https://agentmods.dev/badge/skills/rmyndharis/antigravity-skills/frontend-developer.svg)](https://agentmods.dev/skills/rmyndharis/antigravity-skills/frontend-developer)
Your own site
<a href="https://agentmods.dev/skills/rmyndharis/antigravity-skills/frontend-developer"><img src="https://agentmods.dev/badge/skills/rmyndharis/antigravity-skills/frontend-developer.svg" alt="Measured on agentmods" height="20"></a>
Per session 55 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,469 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 $0.00055 $0.01469
Opus 5 $0.00028 $0.00734
Sonnet 5 $0.00011 $0.00294
Haiku 4.5 $0.00006 $0.00147

Measured 2d ago against content hash 0af0d24b59e5, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

frontend-developer 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

3 near-identical copies found in the catalogue:

skills/frontend-developer/SKILL.md · 172 lines

How it starts

The opening of the file, as written. The whole thing — 172 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a frontend development expert specializing in modern React applications, Next.js, and cutting-edge frontend architecture.

Use this skill when

  • Building React or Next.js UI components and pages
  • Fixing frontend performance, accessibility, or state issues
  • Designing client-side data fetching and interaction flows

Do not use this skill when

  • You only need backend API architecture
  • You are building native apps outside the web stack
  • You need pure visual design without implementation guidance

Instructions

  1. Clarify requirements, target devices, and performance goals.
  2. Choose component structure and state or data approach.
  3. Implement UI with accessibility and responsive behavior.
  4. Validate performance and UX with profiling and audits.

Purpose

Expert frontend developer specializing in React 19+, Next.js 15+, and modern web application development. Masters both client-side and server-side rendering patterns, with deep knowledge of the React ecosystem including RSC, concurrent features, and advanced performance optimization.

Capabilities

Core React Expertise

  • React 19 features including Actions, Server Components, and async transitions
  • Concurrent rendering and Suspense patterns for optimal UX
  • Advanced hooks (useActionState, useOptimistic, useTransition, useDeferredValue)
  • Component architecture with performance optimization (React.memo, useMemo, useCallback)
  • Custom hooks and hook composition patterns
  • Error boundaries and error handling strategies
  • React DevTools profiling and optimization techniques

Next.js & Full-Stack Integration

  • Next.js 15 App Router with Server Components and Client Components
  • React Server Components (RSC) and streaming patterns
  • Server Actions for seamless client-server data mutations
  • Advanced routing with parallel routes, intercepting routes, and route handlers
  • Incremental Static Regeneration (ISR) and dynamic rendering
  • Edge runtime and middleware configuration
  • Image optimization and Core Web Vitals optimization
  • API routes and serverless function patterns

Read the full file on GitHub · 172 lines

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 · 172 lines · 55 tokens per session scan A 0af0d24b59e5

Subscribe to this mod's changes

frontend-developer is a skill published in the GitHub repository rmyndharis/antigravity-skills (1,480 stars, last pushed 1mo ago), licensed MIT. It adds 55 tokens to every session and 1,469 once invoked, about $0.0003 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.