Web & Frontend

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Use this skill when the user says 'gRPC', 'protobuf', 'protocol buffers', 'streaming RPC', 'unary call', 'server streaming', 'client streaming', 'bidirectional streaming', 'gRPC interceptor', 'gRPC error handling', 'protobuf schema', 'service definition', 'RPC design', or when designing gRPC APIs. This skill enforces consistent protobuf schema conventions, streaming patterns, interceptor chains, and structured error handling for gRPC services. Applies to any backend stack using gRPC. Do NOT use for: REST API design, GraphQL schema, message queue design, or frontend data fetching.

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Use this skill when the user says 'CSS strategy', 'CSS Modules', 'CSS-in-JS', 'utility-first CSS', 'Tailwind CSS', 'styled-components', 'Emotion', 'CSS organization', 'CSS architecture', 'CSS approach', 'BEM', 'CSS naming convention', 'CSS preprocessor', 'Sass', 'PostCSS', 'styled-jsx', 'Linaria', 'vanilla-extract', 'CSS decision', 'styling approach'. This skill helps choose the right CSS approach based on project size, team composition, performance requirements, and build tooling. Works with any frontend framework. Do NOT use for: component design (use design-system skill), Tailwind-specific questions (use tailwind-css skill), or design token setup (use theming skill).

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Use this skill when the user says 'tailwind', 'utility css', 'design tokens', 'responsive tailwind', 'tailwind config', 'custom theme'. This skill enforces utility-first CSS principles, design token extraction, responsive breakpoint patterns, and Tailwind config best practices. Applies to any frontend stack.

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Use this skill when the user says 'Spring Boot structure', 'Spring architecture', 'Spring Boot clean arch', 'Spring layered', 'Spring hexagonal', 'Spring WebFlux', 'Spring Data', 'Spring Boot folder', or when building a Spring Boot application. This skill enforces: package-by-feature (not by layer), hexagonal architecture with ports and adapters, Spring stereotypes correctly applied (@Repository in infrastructure, not domain), constructor injection (no @Autowired on fields), and MVC vs WebFlux decision guide. Requires Spring Boot (pom.xml or build.gradle). Do NOT use for: Kotlin Multiplatform, non-Spring Java, or frontend Angular.

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Use this skill when the user says 'accessibility', 'a11y', 'WCAG', 'screen reader', 'ARIA', 'keyboard navigation', 'color contrast', 'focus management', 'semantic HTML', or when ensuring frontend applications are accessible. This skill enforces: semantic HTML first (no div soup), ARIA only when native semantics are insufficient, WCAG 2.2 AA compliance, and automated a11y testing in CI. Works with any frontend framework. Do NOT use for: backend API accessibility, database design, or performance optimization.

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Use this skill when the user says 'bundler', 'Vite', 'Webpack', 'Turbopack', 'build tool', 'bundle config', 'build optimization', 'tree shaking', 'code splitting', 'lazy loading', 'chunk splitting', 'asset bundling', 'build performance', 'bundler migration'. Configure and optimize frontend build tooling. Do NOT use for: framework-specific builds or deployment pipelines.

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Use this skill when the user says 'data fetching', 'TanStack Query', 'SWR', 'React Query', 'server state', 'API client', 'data fetching pattern', 'cache invalidation', 'optimistic update', 'pagination data', 'infinite scroll', 'stale-while-revalidate'. Design data fetching layer for frontend apps. Do NOT use for: backend API design or database queries.

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Use this skill when the user says 'feature flags', 'LaunchDarkly', 'split testing', 'A/B testing', 'gradual rollout', 'canary release', 'feature toggle', 'flag provider', 'targeting rule', or when implementing frontend feature flags. This skill enforces: typed flag definitions, provider-agnostic abstraction layer, gradual rollout with percentage targeting, and A/B test assignment tracking. Works with LaunchDarkly, Split.io, Flagsmith, or custom flag backends. Do NOT use for: backend-only flag evaluation, server-side config management, infrastructure provisioning.

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Use this skill when the user says 'form handling', 'form validation', 'React Hook Form', 'Formik', 'form state', 'form submission', 'field validation', 'form error', 'controlled input', 'uncontrolled input', 'form schema', 'Zod validation', 'form dirty', 'field array'. Implement client-side forms with validation, complex fields, and UX patterns. Do NOT use for: backend validation or API design.

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Use this skill when the user asks about microfrontend, Module Federation, Web Components, iframe integration, shared dependencies, or cross-app communication between frontend applications.

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Use this skill when the user says 'crash report', 'crashlytics', 'sentry', 'symbolication', 'dsym', 'breadcrumb', 'non-fatal', 'user context', 'error tracking'. This skill enforces proper crash reporting patterns: SDK setup, symbolication, breadcrumbs, non-fatal error capture, user context, and release health monitoring. Applies to iOS, Android, Flutter, and React Native.

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Use this skill when the user says 'in-app purchase', 'IAP', 'subscription', 'consumable', 'StoreKit', 'Play Billing', 'receipt validation', 'restore purchase'. This skill enforces proper purchase flow patterns: product configuration, purchase flow, receipt validation, subscription management, and restore handling. Applies to iOS, Android, Flutter, and React Native.

itsual Skill

Verify UI behavior using browser automation, visual checks, and DevTools-style inspection. Use for end-to-end flows, visual regressions, accessibility in the browser, or when unit tests are insufficient for user-facing behavior.

itsual Skill

Audit interfaces for accessibility issues using standards, tools, and manual checks — then prioritize and remediate effectively. Use when evaluating existing products for WCAG conformance, preparing for compliance, or improving inclusive quality.

itsual Skill

Design inclusive interfaces that work for people with diverse abilities, meeting accessibility standards and real user needs. Use when creating or auditing designs for keyboard use, screen readers, contrast, motion sensitivity, and inclusive patterns.

itsual Skill

Evaluate system or component design for scalability, maintainability, security, and alignment with goals. Use when proposing or reviewing significant architectural changes, new services, or major refactors.

itsual Skill

Build production-quality user interfaces with attention to accessibility, performance, responsiveness, and maintainability. Use for any UI work, component development, frontend features, or when the user mentions React, Vue, CSS, design systems, or user-facing interfaces.

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Use this skill when asked about smart contract development, Solidity, Vyper, Rust smart contracts (Solana, NEAR, Polkadot), Haskell/Plutus (Cardano), Cairo/StarkNet, dApp backend development, Truffle, Hardhat, Foundry, Anchor, and blockchain application patterns. Languages: Solidity, Vyper, Rust, Haskell, Cairo, Move. Covers EVM-based development (Ethereum, Polygon, Arbitrum, Optimism), SVM-based development (Solana), eUTxO-based development (Cardano), StarkNet/STARK-based development (Cairo), smart contract security, gas optimization, upgradeable contracts, and cross-contract communication. Do NOT use for: blockchain core protocol (use blockchain-core), web3 frontend (use blockchain-web3), or testing (use blockchain-testing).

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Use this skill when the user says 'auth', 'authentication', 'login', 'signup', 'JWT', 'OAuth', 'OAuth2', 'OpenID Connect', 'route guard', 'protected route', 'auth middleware', 'token storage', 'refresh token', 'session management', 'access token', 'logout', 'SSO', 'magic link', 'passwordless', 'MFA', '2FA'. This skill enforces secure token storage, proper route guard patterns, OAuth flow handling (PKCE, Implicit, Auth Code), refresh token rotation, and session persistence. Works with any frontend framework (React, Vue, Angular, Svelte) and any auth provider (Auth0, Clerk, Supabase, Firebase, Cognito, custom). Do NOT use for: backend auth logic, API token validation, or database-level auth.

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Use this skill when the user says 'error handling', 'error boundary', 'error recovery', 'graceful degradation', 'fallback UI', 'error reporting', 'error logging', 'crash recovery', 'error fallback', 'retry pattern', 'error state', 'error boundary React', 'Vue error handler', 'Angular error handler', 'error boundary Svelte'. This skill enforces error boundary implementation at key UI levels, graceful degradation patterns, error reporting to monitoring services, and user-facing recovery options. Works with any frontend framework (React, Vue, Angular, Svelte). Do NOT use for: API error handling patterns (use data-fetching skill), form validation errors (use form-handling skill), or backend error handling.

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Use this skill when the user says 'web component', 'custom element', 'shadow DOM', 'HTML template', 'CustomElementsRegistry', 'ElementInternals', 'form-associated element', 'cross-framework component', 'vanilla web component'. This skill enforces: custom element lifecycle methods, shadow DOM for style encapsulation, <slot> and <template> patterns, ElementInternals for form participation, and attribute/property reflection for cross-framework compatibility. Requires no specific framework — works in any web project. Do NOT use for: Lit-specific components, framework-specific components (React/Vue/Angular), or projects that should use a library-based approach.

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WebGPU & WebGL: Rendering Pipelines and GPU Memory Optimization

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Use this skill when the user says 'browser caching', 'cache headers', 'service worker', 'SW', 'stale-while-revalidate', 'SWR', 'cache strategy', 'Cache-Control', 'ETag', 'cache busting', 'offline caching', or when optimizing frontend load performance. This skill enforces: Cache-Control headers with appropriate max-age, service worker caching with stale-while-revalidate pattern, cache-busted asset URLs, and offline fallback. Works with any frontend framework. Do NOT use for: backend response caching, CDN configuration, database query caching.

j4flmao Skill

Unity C# scripting and DOTS/ECS mechanics - component systems, Jobs, Burst, archetypes/chunks, async patterns, and C# performance in game code.

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Use this skill when the user says 'database design', 'schema design', 'query optimization', 'slow query', 'migration', 'index', 'ORM', 'repository pattern', 'N+1 problem', 'transaction', or when designing or troubleshooting the data layer. This skill enforces schema design principles, indexing strategy, N+1 detection and fixing, transaction boundaries, migration best practices, and the repository pattern. Applies to PostgreSQL, MySQL, MongoDB, and ORMs (TypeORM, Prisma, SQLAlchemy, Diesel, GORM, Spring Data). Do NOT use for: API design, caching, or frontend state management.

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Blockchain indexing covering The Graph subgraphs, Dune Analytics, Goldsky pipelines, ChainIndex custom indexers, and ETL event-warehousing patterns for blockchain data. Covers event-driven indexing, reorg handling, data source templates, and multi-chain data aggregation. Do NOT use for: web3 frontend data fetching (use blockchain-web3), smart contract development (use blockchain-application), or general ETL (out of scope).

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Use this skill when the user says 'state management', 'global state', 'Redux', 'Zustand', 'Pinia', 'NgRx', 'React Context', 'state architecture', 'where to put state', 'server state vs client state', or when deciding how to manage application state. This skill enforces: server state goes in server state libraries (TanStack Query, SWR, Apollo), local state goes in useState/ref/signals, shared state goes in lightweight stores (Zustand, Pinia, Signal Store), and complex state goes in XState or Redux Toolkit. Works with React, Vue, Angular. Do NOT use for: database design, backend caching, or API design.

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Use this skill when the user says 'push notification', 'APNs', 'FCM', 'remote notification', 'push token', 'notification payload', 'notification channel'. This skill enforces platform-specific push notification patterns: permission flow, token management, payload structure, foreground/background handling, and notification channels. Applies to iOS, Android, Flutter, and React Native.

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Use this skill when the user asks 'where does this code go', 'what layer', 'clean architecture', 'hexagonal', 'ports and adapters', 'domain layer', 'application layer', 'infrastructure layer', 'should this be in service or repository', or when designing or reviewing backend code organization. This skill enforces strict Clean/Hexagonal Architecture layer rules — Domain has ZERO dependencies on infrastructure. Applies to NestJS, Go, Rust, Python, Spring Boot. Do NOT use for: database optimization, API endpoint design, or frontend code organization.

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Use this skill when the user says 'WebSocket', 'real-time', 'socket.io', 'WS connection', 'reconnection', 'WS rooms', 'broadcast', 'WS scaling', 'WS clustering', 'pub/sub over WS', 'SSE', 'Server-Sent Events', 'long polling', 'WS handshake', or when designing real-time communication. This skill enforces consistent WebSocket patterns: connection lifecycle, room management, reconnection strategies, message framing, and horizontal scaling. Applies to any backend stack. Do NOT use for: REST API design, gRPC streaming, message queue design, or frontend rendering.

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Use this skill when the user says 'resilience', 'circuit breaker', 'retry', 'bulkhead', 'timeout', 'fallback', 'resilience4j', 'fault tolerance', 'rate limiter', 'backoff', 'retry strategy', 'bulkhead pattern'. This skill applies production fault-tolerance patterns: circuit breaker, retry with backoff, bulkhead isolation, timeouts, and fallback handlers. Applies to any backend stack. Do NOT use for: infrastructure-level resiliency (K8s liveness probes), database replication, or frontend error handling.

j4flmao Skill

Webpack Module Federation & Rspack: Runtime Dependency Sharing Architecture

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Use this skill when the user says 'image optimization', 'responsive images', 'image CDN', 'lazy loading images', 'next/image', 'srcset', 'picture element', 'WebP', 'AVIF', 'image compression', 'image CDN', 'blur placeholder', 'progressive image'. Optimize images for web performance including format selection, responsive images, lazy loading, and CDN integration. Do NOT use for: video optimization or server-side image processing.

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Use this skill when the user says 'TypeScript patterns', 'generic components', 'type-safe API', 'discriminated unions', 'type guards', 'type narrowing', 'TS patterns', 'type-safe React', or when writing TypeScript for frontend applications. This skill enforces: generic component patterns with proper constraint bounds, type-safe API client wrappers with response typing, discriminated unions for UI state management, and user-defined type guards. Works with React, Vue, Angular, or any TS-based frontend. Do NOT use for: backend type setup, Node.js runtime types, or basic TypeScript syntax questions.

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Use this skill when the user says 'i18n', 'internationalization', 'localization', 'locale switching', 'RTL', 'right-to-left', 'i18next', 'react-intl', 'vue-i18n', 'translation', 'language selector', 'formatjs', 'ICU message format', 'pluralization', 'LTR', 'bidirectional text'. This skill enforces proper i18n library selection, locale switching patterns, RTL/LTR layout support, ICU message syntax, and translation file management. Works with any frontend framework (React, Vue, Angular, Svelte). Do NOT use for: backend i18n, database collation, or content translation workflows.

itsual Skill

Design and implement dark mode (and theming) that maintains hierarchy, accessibility, and brand quality in low-light interfaces. Use when adding dark theme support, refining theme tokens, or ensuring parity between light and dark experiences.