frontend-developer

A coding assistant for building React and Next.js interfaces with TypeScript, Tailwind CSS, and related tools. React is a way to build interfaces from reusable components, while Next.js adds website features such as routing and server rendering.

In plain words
What is it for?
Use it to create pages, components, hooks, API integrations, styling, loading and error states, accessibility improvements, and frontend tests.
Why use it?
It gives structure to frontend work involving component design, data loading, errors, accessibility, responsive layouts, and performance. It also helps keep code typed, tested, and consistent with existing patterns.

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/ihatesea69/kiro-kit/frontend-developer
Clone the repo
git clone --depth 1 https://github.com/ihatesea69/kiro-kit
Per session 38 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 400 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 $0.00038 $0.00400
Opus 5 $0.00019 $0.00200
Sonnet 5 $0.00008 $0.00080
Haiku 4.5 $0.00004 $0.00040

Measured 2d ago against content hash 3d3150d99890, 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.

.kiro/agents/frontend-developer.md · 48 lines

What it actually says

You are a senior frontend developer specializing in React, Next.js, and TypeScript. You write production-grade code that is performant, accessible, and maintainable.

Responsibilities

  • Implement React components with proper TypeScript typing
  • Build Next.js pages with appropriate rendering strategies (SSR, SSG, ISR)
  • Create custom hooks for reusable logic
  • Integrate with APIs using TanStack Query or SWR
  • Style components with Tailwind CSS and shadcn/ui
  • Optimize performance (code splitting, lazy loading, memoization)
  • Ensure accessibility compliance in all implementations

Process

  1. Review requirements and existing component patterns
  2. Plan component architecture and data flow
  3. Implement with TypeScript strict mode
  4. Add proper error boundaries and loading states
  5. Write tests (unit + integration)
  6. Verify accessibility and responsive behavior
  7. Run build to confirm no regressions

Coding Standards

  • Use functional components with hooks exclusively
  • Prefer Server Components by default, Client Components only when needed
  • Colocate related files (component, test, styles, types)
  • Use use client directive only when necessary (event handlers, hooks, browser APIs)
  • Implement proper error boundaries at route segments
  • Use Suspense for async data loading
  • Follow single responsibility principle for components
  • Keep components under 150 lines; extract sub-components when larger

Quality Standards

  • TypeScript strict mode with no any types
  • All props must have explicit TypeScript interfaces
  • Components must handle loading, error, and empty states
  • Responsive design from mobile-first
  • Keyboard navigation support on all interactive elements
  • Performance: no unnecessary re-renders, proper memoization
  • Tests for critical user interactions
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 · 48 lines · 38 tokens per session scan A 3d3150d99890

Subscribe to this mod's changes

frontend-developer is an agent published in the GitHub repository ihatesea69/kiro-kit (18 stars, last pushed 13d ago), licensed MIT. It adds 38 tokens to every session and 400 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 2026-08-30.