Frontend

Grey Haven's comprehensive testing strategy - Vitest unit/integration/e2e for TypeScript, pytest markers for Python, >80% coverage requirement, fixture patterns, and Doppler for test environments. Use when writing tests, setting up test infrastructure, running tests, debugging test failures, improving coverage, configuring CI/CD, or when user mentions 'test', 'testing', 'pytest', 'vitest', 'coverage', 'TDD', 'test-driven development', 'unit test', 'integration test', 'e2e', 'end-to-end', 'test fixtures', 'mocking', 'test setup', 'CI testing'.

UI/UX design intelligence. 50 styles, 21 palettes, 50 font pairings, 20 charts, 8 stacks (React, Next.js, Vue, Svelte, SwiftUI, React Native, Flutter, Tailwind). Actions: plan, build, create, design, implement, review, fix, improve, optimize, enhance, refactor, check UI/UX code. Projects: website, landing page, dashboard, admin panel, e-commerce, SaaS, portfolio, blog, mobile app, .html, .tsx, .vue, .svelte. Elements: button, modal, navbar, sidebar, card, table, form, chart. Styles: glassmorphism, claymorphism, minimalism, brutalism, neumorphism, bento grid, dark mode, responsive, skeuomorphism, flat design. Topics: color palette, accessibility, animation, layout, typography, font pairing, spacing, hover, shadow, gradient.

Use when completing tasks, implementing major features, or before merging to verify work meets requirements

Fetches official documentation for external libraries and frameworks (React, Next.js, Prisma, FastAPI, Express, Tailwind, MongoDB, etc.) with 60-90% token savings via content-type filtering. Use this skill when implementing features using library APIs, debugging library-specific errors, troubleshooting configuration issues, installing or setting up frameworks, integrating third-party packages, upgrading between library versions, or looking up correct API patterns and best practices. Triggers automatically during coding work - fetch docs before writing library code to get correct patterns, not after guessing wrong.

HTML 슬라이드를 PowerPoint(PPTX) 파일로 변환. PPTX 생성, 편집, 썸네일 생성이 필요할 때 사용.

Apply Grey Haven's TanStack ecosystem patterns - Router file-based routing, Query data fetching with staleTime, and Start server functions. Use when building React applications with TanStack Start. Triggers: 'TanStack', 'TanStack Start', 'TanStack Query', 'TanStack Router', 'React Query', 'file-based routing', 'server functions'.

Creates production-grade, reusable skills that extend Claude's capabilities. This skill should be used when users want to create a new skill, improve an existing skill, or build domain-specific intelligence. Gathers context from codebase, conversation, and authentic sources before creating adaptable skills.

Expert React video scene component creator for educational content. Builds production-grade, visually distinctive components using framer-motion animations, pixel-precise positioning, and optimized performance patterns. Follows strict component format with React.memo, threshold-based state updates, and module-level definitions. Outputs self-contained TSX components with proper timing sync, 60fps performance, and comprehensive reference-based implementation.

Build LLM-powered applications and pipelines using proven methodology - task-model fit analysis, pipeline architecture, structured outputs, file-based state, and cost estimation. Use when building AI features, data processing pipelines, agents, or any LLM-integrated system. Inspired by Karpathy's methodology and production case studies.

Specialized testing for React applications using TanStack ecosystem (Query, Router, Table, Form) with Vite and Vitest. Use when testing React + TanStack apps, mocking server state, testing router, or validating query behavior. Triggers: 'TanStack testing', 'React Query testing', 'test TanStack', 'mock query', 'router test'.

Apply Bootstrapped AI Methodology Engineering (BAIME) to develop project-specific methodologies through systematic Observe-Codify-Automate cycles with dual-layer value functions (instance quality + methodology quality). Use when creating testing strategies, CI/CD pipelines, error handling patterns, observability systems, or any reusable development methodology. Provides structured framework with convergence criteria, agent coordination, and empirical validation. Validated in 8 experiments with 100% success rate, 4.9 avg iterations, 10-50x speedup vs ad-hoc. Works for testing, CI/CD, error recovery, dependency management, documentation systems, knowledge transfer, technical debt, cross-cutting concerns.

Turn the idea for a feature into a fully-formed PRD/design/specification and implementation-plan. Use in pre-implementation (idea-to-design) stages to make sure you understand the requirements and have a correct implementation plan before writing actual code.

Use when you have a spec or requirements for a multi-step task, before touching code

Browser automation using Playwright MCP. Navigate websites, fill forms, click elements, take screenshots, and extract data. Use for web browsing, form submission, web scraping, or UI testing. NOT for static content (use curl/wget).

Comprehensive performance analysis and optimization for algorithms (O(n²)→O(n)), databases (N+1 queries, indexes), React (memoization, virtual lists), bundles (code splitting), API caching, and memory leaks. 85%+ improvement rate. Use when application is slow, response times exceed SLA, high CPU/memory usage, performance budgets needed, or when user mentions 'performance', 'slow', 'optimization', 'bottleneck', 'speed up', 'latency', 'memory leak', or 'performance tuning'.

Generate production-ready project scaffolds for Grey Haven stack with Cloudflare Workers, React + TypeScript, Python + Pydantic, PlanetScale, proper structure, and configuration. Use when starting new projects, creating microservices, setting up monorepo workspaces, initializing projects, or when user mentions 'new project', 'project scaffold', 'project template', 'project setup', 'bootstrap project', 'project starter', or 'initialize project'.

Use when styling Rails views - Tailwind CSS utility-first framework and DaisyUI component library with theming

Systematic API design methodology with 6 validated patterns covering parameter categorization, safe refactoring, audit-first approach, automated validation, quality gates, and example-driven documentation. Use when designing new APIs, improving API consistency, implementing breaking change policies, or building API quality enforcement. Provides deterministic decision trees (5-tier parameter system), validation tool architecture, pre-commit hook patterns. Validated with 82.5% cross-domain transferability, 37.5% efficiency gains through audit-first refactoring.

Comprehensive test suite generation with unit tests, integration tests, edge cases, and error handling. Use when generating tests for existing code, improving coverage, or creating systematic test suites. Triggers: 'generate tests', 'add tests', 'test coverage', 'write tests for', 'create test suite'.

프레젠테이션 슬라이드를 미려한 HTML로 디자인. 슬라이드 HTML 생성, 시각적 디자인, 레이아웃 구성이 필요할 때 사용.