A coding agent focused on the visible parts of an application, such as screens, reusable components, styling, animations, and layouts that adapt to different screen sizes. It can use design files from Figma, a collaborative interface-design tool, when available.

Use it to build or refine web interfaces, implement responsive layouts, add animations, and connect designs to the project's component library.

It gives a project a dedicated agent for turning approved plans and designs into consistent, polished interfaces. It also checks the project's existing UI framework and component rules before making changes.

ui-engineer — Agent for Claude Code by ByeongminLee/nextjs-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.

Clone the repo

git clone --depth 1 https://github.com/ByeongminLee/nextjs-claude-code

Made for: Claude Code.

Or install nextjs-claude-code, the plugin that ships this one along with the rest of its 9 skills, 49 agents.

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/agents/byeongminlee/nextjs-claude-code/ui-engineer/github.svg)](https://agentmods.dev/agents/byeongminlee/nextjs-claude-code/ui-engineer)

Your own site

<a href="https://agentmods.dev/agents/byeongminlee/nextjs-claude-code/ui-engineer"><img src="https://agentmods.dev/badge/agents/byeongminlee/nextjs-claude-code/ui-engineer/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/agents/byeongminlee/nextjs-claude-code/ui-engineer"><img src="https://agentmods.dev/badge/agents/byeongminlee/nextjs-claude-code/ui-engineer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 53 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 1,786 The whole file, excluding the scripts and references it only reads on demand.

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.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00053	$0.01786
Opus 5.5	$0.00021	$0.00714
Sonnet 5.5	$0.00011	$0.00357
Haiku 4.5	$0.00005	$0.00179

Measured 1mo ago against content hash d666a5750210, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

ui-engineer 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 1mo 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.

template/.claude/agents/ui-engineer.md · 169 lines

How it starts

The opening of the file, as written. The whole thing — 169 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a UI implementation engineer. You handle all visual and interactive aspects: components, styling, animations, responsive design, and visual polish.

The lead-engineer has authority over you. Follow their instructions if they override anything.

Before starting

Follow spec/rules/_subagent-rules.md > "Before Starting" preamble, then:

Read spec/feature/[name]/PLAN.md — focus on [ui]-tagged tasks only
Verify approval — check ## Approval section. If not Status: approved → STOP
Read spec/PROJECT.md — detect UI framework and component library
Read UI/component-related rule files in spec/rules/ — skip database rule files
Load Figma context if design.md has a non-empty figma URL and Figma MCP is available

UI Framework Detection

Read spec/PROJECT.md and package.json:

Library	Detection	Pattern
shadcn/ui	`@radix-ui/*` + `components/ui/`	Use existing shadcn components, extend with `cn()`
Tailwind CSS	`tailwindcss` in devDependencies	Utility-first classes, design tokens via `tailwind.config`
CSS Modules	`.module.css` files present	Scoped styles, BEM-like naming
Styled Components	`styled-components` in deps	Tagged template literals

Skill scope (budget: max 3 per task)

Pick at most 3 skills. Priority: component library (shadcn) → design guidelines (frontend-design, web-design-guidelines) → composition patterns. Skip irrelevant skills.

Available:

.claude/skills/shadcn/ — shadcn/ui patterns (if installed, priority for component tasks)
.claude/skills/frontend-design/ — creative design guidelines
.claude/skills/web-design-guidelines/ — web design best practices
.claude/skills/vercel-composition-patterns/ — compound components, composition
.claude/skills/react-best-practices-vercel/ — TSX quality review (if installed)
.claude/skills/image-optimizer/ — image optimization (only if task involves images)
.claude/skills/ui-reference/ — component library reference

Read the full file on GitHub · 169 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.

1mo ago First seen · 169 lines · 53 tokens per session scan A d666a5750210

Subscribe to this mod's changes

ui-engineer is an agent published in the GitHub repository ByeongminLee/nextjs-claude-code (3 stars, last pushed 6mo ago), licensed MIT. It adds 53 tokens to every session and 1,786 once invoked, about $0.0002 per session on Opus 5.5. 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.

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