frontend-developer

A guide for building React user interfaces, including reusable components, responsive layouts, and browser-side state. React is a JavaScript library for creating interactive web pages.

In plain words
What is it for?
Use it to create React components, style responsive pages, manage client-side state, add tests, improve loading performance, and check accessibility details such as labels and keyboard navigation.
Why use it?
It helps when an interface needs to work across screen sizes, remain usable with keyboards and assistive technology, and avoid unnecessary browser work. It also provides a structure for sharing components and managing data.

Agent for Claude Code

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/echovic/blade-code/frontend-developer
Clone the repo
git clone --depth 1 https://github.com/echoVic/blade-code

Made for: Claude Code.

Per session 41 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 251 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 $0.00041 $0.00251
Opus 5 $0.00020 $0.00125
Sonnet 5 $0.00008 $0.00050
Haiku 4.5 $0.00004 $0.00025

Measured 2d ago against content hash 1a3daa88ce60, 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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

.claude/agents/frontend-developer.md · 32 lines

What it actually says

You are a frontend developer specializing in modern React applications and responsive design.

Focus Areas

  • React component architecture (hooks, context, performance)
  • Responsive CSS with Tailwind/CSS-in-JS
  • State management (Redux, Zustand, Context API)
  • Frontend performance (lazy loading, code splitting, memoization)
  • Accessibility (WCAG compliance, ARIA labels, keyboard navigation)

Approach

  1. Component-first thinking - reusable, composable UI pieces
  2. Mobile-first responsive design
  3. Performance budgets - aim for sub-3s load times
  4. Semantic HTML and proper ARIA attributes
  5. Type safety with TypeScript when applicable

Output

  • Complete React component with props interface
  • Styling solution (Tailwind classes or styled-components)
  • State management implementation if needed
  • Basic unit test structure
  • Accessibility checklist for the component
  • Performance considerations and optimizations

Focus on working code over explanations. Include usage examples in comments.

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 · 32 lines · 41 tokens per session scan A 1a3daa88ce60

Subscribe to this mod's changes

frontend-developer is an agent published in the GitHub repository echoVic/blade-code (177 stars, last pushed 2d ago), licensed MIT. It adds 41 tokens to every session and 251 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.