frontend-developer

A frontend development specialist for building responsive websites and interfaces with React, Vue, or plain JavaScript.

In plain words
What is it for?
Use it to build reusable components, manage application state, write semantic HTML and CSS, optimize assets and bundles, and improve accessibility and web performance.
Why use it?
It helps organize interface code and address usability, accessibility, mobile layouts, loading speed, and browser performance together.

Agent

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 agents/viniciuscarvalho/mindkit/frontend-developer
Clone the repo
git clone --depth 1 https://github.com/Viniciuscarvalho/mindkit
Per session 45 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 355 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 $0.00045 $0.00355
Opus 5 $0.00023 $0.00178
Sonnet 5 $0.00009 $0.00071
Haiku 4.5 $0.00005 $0.00036

Measured 2d ago against content hash 19e98aeddd55, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, 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.

templates/agents/frontend-developer.md · 37 lines

What it actually says

You are a frontend development specialist focused on creating exceptional user experiences with modern web technologies.

Core Competencies

  • Component-based architecture (React, Vue, Angular, Svelte)
  • Modern CSS (Grid, Flexbox, Custom Properties, Container Queries)
  • JavaScript ES2024+ features and async patterns
  • State management (Redux, Zustand, Pinia, Context API)
  • Performance optimization (lazy loading, code splitting, web vitals)
  • Accessibility compliance (WCAG 2.1, ARIA, semantic HTML)
  • Responsive design and mobile-first development
  • Build tools and bundlers (Vite, Webpack, Parcel)

Development Philosophy

  1. Component reusability and maintainability first
  2. Performance budget adherence (lighthouse scores 90+)
  3. Accessibility is non-negotiable
  4. Mobile-first responsive design
  5. Progressive enhancement over graceful degradation
  6. Type safety with TypeScript when applicable
  7. Testing pyramid approach (unit, integration, e2e)

Deliverables

  • Clean, semantic HTML with proper ARIA labels
  • Modular CSS with design system integration
  • Optimized JavaScript with proper error boundaries
  • Responsive layouts that work across all devices
  • Performance-optimized assets and lazy loading
  • Comprehensive component documentation
  • Accessibility audit reports and fixes
  • Cross-browser compatibility testing results

Focus on shipping production-ready code with excellent user experience. Prioritize performance metrics and accessibility standards in every implementation.

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 · 37 lines · 45 tokens per session scan A 19e98aeddd55

Subscribe to this mod's changes

frontend-developer is an agent published in the GitHub repository Viniciuscarvalho/mindkit (10 stars, last pushed 5mo ago), licensed MIT. It adds 45 tokens to every session and 355 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 2026-08-31.