Skill UI

This skill specializes in writing, debugging, and refactoring modern JavaScript code (ES2023+). It covers advanced patterns like async/await, Promise handling, ESM modules, and optimal performance for both browser and Node.js environments. Use it for vanilla applications, complex async flows, and performance optimization.

Streamline Microsoft Clarity analytics exports inside Claude Code via the Composio integration, fetching heatmaps, session metrics, and engagement data segmented by browser, device, location, source, medium, campaign, channel, or URL over the last 1-3 days.

This guide provides expert patterns for implementing secure, full-stack authentication in Next.js using Supabase. It covers essential architectural components, including setting up separate browser and server clients, utilizing middleware for route protection and session refreshing, handling OAuth callbacks, and implementing auth operations safely via Server Actions and Server Components. Essential knowledge for building secure, modern web applications.

Build single-file HTML playgrounds with controls, live preview, and prompt output so users can explore large visual or structural spaces and copy actionable prompts without leaving the browser.

A specialist skill for writing robust, maintainable, and scalable End-to-End (E2E) tests using Playwright. This guide covers setting up test infrastructure, implementing Page Object Model (POM), using role-based selectors, handling API mocking, and debugging flaky tests. Ideal for integrating quality checks into CI/CD pipelines and performing complex browser automation.

Provides Playwright-powered browser automation that detects dev servers, writes tests to /tmp, launches a visible Chromium, and exercises login flows, responsive layouts, form submissions, link checks, or any browser task to validate web functionality.

Provides a comprehensive workflow for managing feature flags, running A/B/multivariate experiments, and analyzing user cohorts using PostHog. The guide covers implementing flag evaluation both client-side (browser) and server-side (Node.js), and demonstrates how to programmatically set up, track, and query experiment results via API calls (cURL/Bash).

This skill guides the complete setup and configuration of PostHog SDKs for modern applications. It covers best practices for implementing client-side (browser) and server-side (Node.js/Python) event tracking. Users will learn how to install the necessary SDKs via npm or pip, manage environment variables for both Project API Keys and secure Personal API Keys, and initialize the tracking service correctly to ensure accurate and reliable event capture in PostHog.

Provides a comprehensive guide and framework for executing end-to-end (E2E) tests. It simulates real user interactions across the entire application stack, covering browser UI, API calls, and database operations. The guide details best practices like implementing the Page Object Model (POM), configuring multi-browser environments (Playwright, Cypress, Selenium), and establishing robust error handling mechanisms to ensure high application stability and quality.

This guide provides a comprehensive, multi-language walkthrough for installing and initializing the Sentry SDK in various environments (Node.js, Python, Browser). It covers essential concepts like DSN setup, using secure environment variables, configuring release versions, and implementing basic error and performance tracking for robust observability in production and CI/CD pipelines.

This skill validates web applications across diverse browsers (Chromium, Gecko, WebKit) and real mobile devices. It supports both local testing using Playwright and scalable cloud testing via major platforms like BrowserStack, Sauce Labs, and Kobiton. Use it when ensuring consistent UI/UX, correct CSS rendering, and functional JavaScript behavior regardless of the target environment or device type.

This comprehensive workflow provides a complete cycle of quality assurance for software development. It covers every stage from defining the test strategy (TDD, Unit Testing) through integration, E2E testing, browser automation, performance profiling, security scanning, and final code review. Use this when setting up robust testing infrastructure or ensuring production-ready software quality.