Analyze what code will be affected by changes. Use when user asks "what will break if I change X", "impact of changing X", "dependencies of X", "is it safe to modify X", or before making significant code changes.
Trace code execution paths and data flow. Use when user asks "how does X work", "what happens when X", "trace the flow of X", "where does data come from", or needs to understand feature implementation.
Expert database optimizer specializing in query optimization, performance tuning, and scalability across multiple database systems. Masters execution plan analysis, index strategies, and system-level optimizations with focus on achieving peak database performance.
Expert developer experience optimizer specializing in build performance, tooling efficiency, and workflow automation. Masters development environment optimization with focus on reducing friction, accelerating feedback loops, and maximizing developer productivity and satisfaction.
Systematic debugging methodologies, troubleshooting workflows, logging strategies, error tracking, performance profiling, stack trace analysis, and debugging tools across languages and environments. Covers local debugging, distributed systems, production issues, and root cause analysis.
Use when debugging web applications in chrome via the remote debugging protocol. Provides capabilities for inspecting DOM, executing JS, taking screenshots, and automating browser interactions.
Expert performance engineer specializing in system optimization, bottleneck identification, and scalability engineering. Masters performance testing, profiling, and tuning across applications, databases, and infrastructure with focus on achieving optimal response times and resource efficiency.
Expert in React Native 0.83+ and Expo SDK 54+ environment setup. Helps with Node.js 20+, Xcode 16.1+, Android Studio, watchman, CocoaPods, EAS Build, simulators, emulators, and troubleshooting. Activates for environment setup, installation issues, xcode setup, android studio, simulators, emulators, react-native init, expo init, development environment, SDK configuration, EAS Build, development builds.
Performance engineering expert for optimization, profiling, benchmarking, and scalability. Analyzes performance bottlenecks, optimizes database queries, improves frontend performance, reduces bundle size, implements caching strategies, optimizes algorithms, and ensures system scalability. Activates for performance, optimization, slow, latency, profiling, benchmark, scalability, caching, Redis cache, CDN, bundle size, code splitting, lazy loading, database optimization, query optimization, N+1 problem, indexing, algorithm complexity, Big O, memory leak, CPU usage, load testing, stress testing, performance metrics, Core Web Vitals, LCP, FID, CLS, TTFB.
Expert in React Native 0.83+ performance optimization including Hermes V1, React 19.2 concurrent features, Intersection Observer, Web Performance APIs, bundle size reduction, memory management, rendering optimization, FlashList, expo-image v2, memoization, lazy loading, code splitting. Activates for performance, slow app, lag, memory leak, bundle size, optimization, flatlist performance, re-render, fps, jank, startup time, app size, hermes, concurrent rendering.
Debugger Specialist. Use this for Root Cause Analysis (RCA), reproduction scripts, and scientific debugging protocols. Follows the Iron Law "No Fix Without Root Cause".
Getting started guides for BlazeMeter, including onboarding, migration guides, continuous testing journey, glossary, and mobile testing. Use when getting started with BlazeMeter for (1) Navigating BlazeMeter University onboarding, (2) Migrating from Runscope or JMeter, (3) Understanding the continuous testing journey, (4) Referencing BlazeMeter terminology, (5) Testing mobile sites and apps, or any other getting started tasks.
Expert in Metro bundler configuration, optimization, troubleshooting, caching strategies, custom transformers, asset management, source maps, bundling performance. Activates for metro, metro bundler, metro.config.js, bundler, bundle, cache, transformer, asset resolver, metro cache, bundling error, unable to resolve module, port 8081.
生成可读性报告。当用户请求为项目源代码生成可读性报告时，使用此功能。输出名为 readability-report.html 的单页 HTML 文件作为可读性报告，该报告集成了 Node.js 脚本和 HTML 模板。
Use when reviewing Bknd code, debugging issues, or checking for common mistakes. Covers anti-patterns, gotchas, known bugs, and troubleshooting strategies for Bknd v0.20.x applications. Use this skill to identify problems in existing code or prevent issues when writing new code.
Multi-framework UI testing expert - Cypress, Testing Library, component tests. Use for framework comparison, Cypress-specific testing, or React Testing Library. For DEEP Playwright expertise, use e2e-playwright skill instead. Activates for Cypress, Testing Library, component tests, React testing, Vue testing, framework comparison, which testing tool, Cypress vs Playwright, render component, fireEvent, userEvent, screen queries, getByRole, getByText, getByTestId, waitFor, findBy, queryBy, test component, mount component, shallow render, integration test UI, DOM testing, accessibility testing, aria queries, form testing, user interaction testing, click test, input test.
Expert in React Native testing strategies including unit tests with Jest, integration tests, E2E tests with Detox, component testing with React Native Testing Library, snapshot testing, mocking native modules, testing on simulators and real devices. Activates for testing, jest, detox, e2e, unit test, integration test, component test, test runner, mock, snapshot test, testing library, react native testing library, test automation.
Expert in debugging React Native and Expo mobile applications. Covers React DevTools, Flipper, Chrome DevTools, network debugging, crash analysis, error boundaries, debugging native modules, remote debugging, breakpoints, console logging strategies. Activates for debugging mobile app, react native debugging, flipper, devtools, breakpoints, crash, error, remote debugging, network request debugging, console.log, debugger, react native debugger.
Building Expo DevTools Plugins with CLI Interfaces for interacting with running Expo apps using agents.
Use to audit test quality with Google Fellow SRE scrutiny - identifies tautological tests, coverage gaming, weak assertions, missing corner cases. Creates bd epic with tasks for improvements, then runs SRE task refinement on each.
