debug-and-refactor

Debug Angular applications systematically with expert-level diagnostic techniques. This skill provides comprehensive guidance for troubleshooting dependency injection errors, change detection issues (NG0100), RxJS subscription leaks, lazy loading failures, zone.js problems, and common Angular runtime errors. Includes structured four-phase debugging methodology, Angular DevTools usage, console debugging utilities (ng.probe), and performance profiling strategies for modern Angular applications.

Debug Django web applications with systematic diagnostic approaches. This skill covers troubleshooting Django-specific errors including TemplateDoesNotExist, ImproperlyConfigured, IntegrityError, migration conflicts, CSRF failures, N+1 query problems, and circular imports. Includes Django Debug Toolbar setup, ORM query logging, pdb/ipdb usage, shell_plus debugging, and comprehensive logging configuration. Provides four-phase methodology for root cause analysis and regression prevention.

Debug Docker containers, images, and infrastructure with systematic diagnostic techniques. This skill provides comprehensive guidance for troubleshooting container exit codes, OOM kills, image build failures, networking issues, volume mount problems, and permission errors. Covers four-phase debugging methodology from quick assessment to deep analysis, essential Docker commands, debug container techniques for minimal images, and platform-specific troubleshooting for Windows, Mac, and Linux.

Debug ASP.NET Core and .NET applications with systematic diagnostic approaches. This skill covers troubleshooting dependency injection container errors, middleware pipeline issues, Entity Framework Core query problems, configuration binding failures, authentication/authorization issues, and startup failures. Includes Visual Studio and VS Code debugging, dotnet-trace, dotnet-dump, dotnet-counters tools, Serilog configuration, Application Insights integration, and four-phase debugging methodology.

Debug Express.js and Node.js applications with systematic diagnostic techniques. This skill provides comprehensive guidance for troubleshooting middleware execution issues, routing problems, CORS errors, async error handling, memory leaks, and unhandled promise rejections. Covers DEBUG environment variable usage, Node Inspector with Chrome DevTools, VS Code debugging, Morgan request logging, and diagnostic middleware patterns. Includes four-phase debugging methodology and common error message reference.

Debug FastAPI applications systematically with this comprehensive troubleshooting skill. Covers async/await issues, Pydantic validation errors (422 responses), dependency injection failures, CORS configuration problems, database session management, and circular import resolution. Provides structured four-phase debugging methodology with FastAPI-specific tools including uvicorn logging, OpenAPI docs, and middleware debugging patterns.

Debug Flask applications systematically with this comprehensive troubleshooting skill. Covers routing errors (404/405), Jinja2 template issues, application context problems, SQLAlchemy session management, blueprint registration failures, and circular import resolution. Provides structured four-phase debugging methodology with Flask-specific tools including Werkzeug debugger, Flask-DebugToolbar, and Flask shell for interactive investigation.

Debug Flutter applications systematically with this comprehensive troubleshooting skill. Covers RenderFlex overflow errors, setState() after dispose() issues, null check operator failures, platform channel problems, build context errors, and hot reload failures. Provides structured four-phase debugging methodology with Flutter DevTools, widget inspector, performance profiling, and platform-specific debugging for Android, iOS, and web targets.

Debug Kubernetes clusters and workloads systematically with this comprehensive troubleshooting skill. Covers CrashLoopBackOff, ImagePullBackOff, OOMKilled, pending pods, service connectivity issues, PVC binding failures, and RBAC permission errors. Provides structured four-phase debugging methodology with kubectl commands, ephemeral debug containers, and essential one-liners for diagnosing pod, service, network, and storage problems across namespaces.

Debug Laravel applications systematically with this comprehensive troubleshooting skill. Covers class/namespace errors, database SQLSTATE issues, route problems (404/405), Blade template errors, middleware issues (CSRF/auth), queue job failures, and cache/session problems. Provides structured four-phase debugging methodology with Laravel Telescope, Debugbar, Artisan tinker, and logging best practices for development and production environments.

Debug NestJS issues systematically. Use when encountering dependency injection errors like "Nest can't resolve dependencies", module import issues, circular dependencies between services or modules, guard and interceptor problems, decorator configuration issues, microservice communication errors, WebSocket gateway failures, pipe validation errors, or any NestJS-specific runtime issues requiring diagnosis.

Debug Next.js issues systematically. Use when encountering SSR errors, hydration mismatches like "Text content did not match", routing issues with App Router or Pages Router, build failures, dynamic import problems, API route errors, middleware issues, caching and revalidation problems, or performance bottlenecks. Covers both Pages Router and App Router architectures.

Debug Nuxt.js issues systematically. Use when encountering SSR errors, Nitro server issues, hydration mismatches like "Hydration text/node mismatch", composable problems with useFetch or useAsyncData, plugin initialization failures, module conflicts, auto-import issues, or Vue-specific runtime errors in a Nuxt context.

Debug Pandas issues systematically. Use when encountering DataFrame errors, SettingWithCopyWarning, KeyError on column access, merge and join mismatches with unexpected NaN values, memory errors with large DataFrames, dtype conversion issues, index alignment problems, or any data manipulation errors in Python data analysis workflows.

Debug PyTorch issues systematically. Use when encountering tensor errors, CUDA out of memory errors, gradient problems like NaN loss or exploding gradients, shape mismatches between layers, device conflicts between CPU and GPU, autograd graph issues, DataLoader problems, dtype mismatches, or training instabilities in deep learning workflows.

Debug Rails issues systematically. Use when encountering ActiveRecord errors like RecordNotFound, routing issues, N+1 query problems detected by Bullet, asset pipeline issues, migration failures, gem conflicts, ActionController errors, CSRF token problems, or any Ruby on Rails application errors requiring diagnosis.

Debug React Native issues systematically. Use when encountering native module errors like "Native module cannot be null", Metro bundler issues including port conflicts and cache corruption, platform-specific build failures for iOS CocoaPods or Android Gradle, bridge communication problems, Hermes engine bytecode compilation failures, red screen fatal errors, or New Architecture migration issues with TurboModules and Fabric renderer.

Debug React issues systematically. Use when encountering component errors like "Cannot read property of undefined", infinite re-render loops with "Too many re-renders", stale closures in hooks, key prop warnings, memory leaks with useEffect, hydration mismatches in SSR/SSG applications, hook rule violations, missing dependency warnings, or performance bottlenecks. Covers functional components, hooks, and modern React 18/19 patterns including Server Components and concurrent features.

Debug Scikit-learn issues systematically. Use when encountering model errors like NotFittedError, shape mismatches between train and test data, NaN/infinity value errors, pipeline configuration issues, convergence warnings from optimizers, cross-validation failures due to class imbalance, data leakage causing suspiciously high scores, or preprocessing errors with ColumnTransformer and feature alignment.

Debug Spring Boot issues systematically. Use when encountering bean errors like NoSuchBeanDefinitionException, circular dependency issues, application startup failures, JPA/Hibernate problems including LazyInitializationException and N+1 queries, security misconfigurations causing 403 Forbidden errors, property binding failures, CSRF token issues, or any Spring Boot application requiring diagnosis with Actuator endpoints and JVM debugging.

Debug Svelte application issues systematically. This skill helps diagnose and resolve Svelte-specific problems including reactivity failures, runes issues ($state, $derived, $effect), store subscription memory leaks, SSR hydration mismatches, and compiler warnings. Covers both Svelte 4 legacy patterns and Svelte 5 runes-based reactivity. Provides debugging tools like $inspect(), {@debug} tags, and svelte-check CLI usage.

Debug SwiftUI application issues systematically. This skill helps diagnose and resolve SwiftUI-specific problems including view update failures, state management issues with @State/@Binding/@ObservedObject, NavigationStack problems, memory leaks from retain cycles, preview crashes, Combine publisher issues, and animation glitches. Provides Xcode debugger techniques, Instruments profiling, and LLDB commands for iOS/macOS development.

Debug TensorFlow and Keras issues systematically. This skill helps diagnose and resolve machine learning problems including tensor shape mismatches, GPU/CUDA detection failures, out-of-memory errors, NaN/Inf values in loss functions, vanishing/exploding gradients, SavedModel loading errors, and data pipeline bottlenecks. Provides tf.debugging assertions, TensorBoard profiling, eager execution debugging, and version compatibility guidance.

Debug Terraform infrastructure-as-code issues systematically. This skill helps diagnose and resolve Terraform-specific problems including state lock conflicts, provider authentication failures, resource dependency cycles, state drift detection, import failures, module version conflicts, and plan/apply errors. Provides TF_LOG debugging, terraform console usage, state manipulation commands, and CI/CD best practices for infrastructure automation.

Debug Vue.js 3 application issues systematically. This skill helps diagnose and resolve Vue-specific problems including reactivity failures with ref/reactive, component update issues, Pinia store state management problems, computed property caching bugs, Teleport/Suspense rendering issues, and SSR hydration mismatches. Provides Vue DevTools usage, console debugging techniques, Vite dev server troubleshooting, and vue-tsc type checking guidance.

Refactor Angular code to improve maintainability, readability, and adherence to best practices. Transforms large components, nested subscriptions, and outdated patterns into clean, modern Angular code. Applies signals, standalone components, OnPush change detection, proper RxJS patterns, and Angular Style Guide conventions. Identifies and fixes memory leaks, function calls in templates, fat components, and missing lazy loading.

Refactor Django/Python code to improve maintainability, readability, and adherence to best practices. Transforms fat views, N+1 queries, and outdated patterns into clean, modern Django code. Applies Python 3.12+ features like type parameter syntax and @override decorator, Django 5+ patterns like GeneratedField and async views, service layer architecture, and PEP 8 conventions. Identifies and fixes anti-patterns including mutable defaults, bare exceptions, and improper ORM usage.

Refactor Docker configurations to improve security, performance, and maintainability. Transforms insecure Dockerfiles and docker-compose files into production-ready containers following 2025 best practices. Implements multi-stage builds, non-root users, pinned image versions, health checks, secrets management, and network segmentation. Fixes common anti-patterns like running as root, hardcoded credentials, missing .dockerignore, and bloated images.

Refactor ASP.NET Core/C# code to improve maintainability, readability, and adherence to best practices. Transforms fat controllers, duplicate code, and outdated patterns into clean, modern .NET code. Applies C# 12 features like primary constructors and collection expressions, SOLID principles, Clean Architecture patterns, and proper dependency injection. Identifies and fixes anti-patterns including service locator, captive dependencies, and missing async/await patterns.

Refactor Express.js/Node.js code to improve maintainability, readability, and adherence to best practices. Transforms callback hell, fat route handlers, and outdated patterns into clean, modern JavaScript/TypeScript code. Applies async/await, controller-service-repository architecture, proper middleware patterns, and ESM modules. Identifies and fixes anti-patterns including blocking event loop, improper error handling, forEach with async callbacks, and memory leaks.

Refactor FastAPI/Python code to improve maintainability, readability, and adherence to best practices. This skill transforms working code into exemplary code following FastAPI patterns, Pydantic v2, and SOLID principles. It addresses fat route handlers, blocking I/O in async routes, code duplication, deep nesting, missing type hints, and improper dependency injection. Apply when you notice business logic in routes, Pydantic v1 patterns, or code violating PEP 8 conventions.

Refactor Flask code to improve maintainability, readability, and adherence to best practices. This skill transforms Flask applications using the application factory pattern, Blueprint organization, and service layer separation. It addresses fat route handlers, missing error handling, improper context local usage, and security issues. Apply when you notice global app instances, routes without Blueprints, business logic in handlers, or missing CSRF protection.

Refactor Flutter/Dart code to improve maintainability, readability, and performance. This skill applies Dart 3 features like records, patterns, and sealed classes, implements proper state management with Riverpod or BLoC, and uses Freezed for immutable models. It addresses monolithic widgets, missing const constructors, improper BuildContext usage, and deep nesting. Apply when you notice widgets doing too much, performance issues from unnecessary rebuilds, or legacy Dart 2 patterns.

Refactor Kubernetes configurations to improve security, reliability, and maintainability. This skill applies defense-in-depth security principles, proper resource constraints, and GitOps patterns using Kustomize or Helm. It addresses containers running as root, missing health probes, hardcoded configs, and duplicate YAML across environments. Apply when you notice security vulnerabilities, missing Pod Disruption Budgets, or :latest image tags in production.

Refactor PHP/Laravel code to improve maintainability, readability, and adherence to best practices. This skill transforms code using modern PHP 8.3+/8.4+ features like property hooks and typed constants, Laravel 11+ patterns including Actions and simplified structure, and SOLID principles. It addresses fat controllers, code duplication, N+1 queries, and missing type declarations. Apply when you notice business logic in controllers or legacy PHP patterns.

Refactor NestJS/TypeScript code to improve maintainability, readability, and adherence to best practices. Identifies and fixes circular dependencies, god object services, fat controllers with business logic, deep nesting, and SRP violations. Applies NestJS patterns including proper module organization, provider scopes, custom decorators, guards, interceptors, pipes, DTOs with class-validator, exception filters, CQRS, repository pattern, and event-driven architecture. Transforms code into exemplary implementations following SOLID principles.

Refactor Next.js code to improve maintainability, readability, and adherence to App Router best practices. Identifies and fixes God Components, prop drilling, inappropriate 'use client' usage, outdated Pages Router patterns, missing Suspense boundaries, incorrect caching strategies, and useEffect data fetching anti-patterns. Applies modern Next.js 15 patterns including Server Components, Client Components, Server Actions, streaming with Suspense, proper caching strategies, Container-Presentational pattern, layout composition, parallel routes, and intercepting routes.

Refactor Nuxt.js/Vue code to improve maintainability, readability, and adherence to best practices. Identifies and fixes DRY violations, oversized components, deep nesting, SRP violations, data fetching anti-patterns with useFetch/useAsyncData/$fetch, poor composable organization, and mixed business/presentation logic. Applies Nuxt 3 patterns including auto-imports, proper data fetching, single-responsibility composables, TypeScript integration, runtime config, Nitro server routes, Nuxt Layers, middleware patterns, Pinia state management, and performance optimizations.

Refactor Pandas code to improve maintainability, readability, and performance. Identifies and fixes loops/.iterrows() that should be vectorized, overuse of .apply() where vectorized alternatives exist, chained indexing patterns, inplace=True usage, inefficient dtypes, missing method chaining opportunities, complex filters, merge operations without validation, and SettingWithCopyWarning patterns. Applies Pandas 2.0+ features including PyArrow backend, Copy-on-Write, vectorized operations, method chaining, .query()/.eval(), optimized dtypes, and pipeline patterns.

Refactor PyTorch code to improve maintainability, readability, and adherence to best practices. Identifies and fixes DRY violations, long functions, deep nesting, SRP violations, and opportunities for modular components. Applies PyTorch 2.x patterns including torch.compile optimization, Automatic Mixed Precision (AMP), optimized DataLoader configuration, modular nn.Module design, gradient checkpointing, CUDA memory management, PyTorch Lightning integration, custom Dataset classes, model factory patterns, weight initialization, and reproducibility patterns.

Refactor Ruby on Rails code to improve maintainability, readability, and adherence to best practices. This skill transforms messy Rails code into elegant, well-structured solutions following Rails conventions and modern Ruby best practices. It addresses fat controllers and models, extracts business logic into service objects, applies DRY principles, uses concerns for shared behavior, implements query objects for complex database operations, and leverages Rails 8 and Ruby 3.3+ features including pattern matching and Data classes.

Refactor React Native and TypeScript code to improve maintainability, readability, and performance for cross-platform mobile applications. This skill transforms complex mobile code into clean, well-structured solutions following React Native New Architecture patterns including Fabric, TurboModules, and JSI. It addresses FlatList performance issues, prop drilling, platform-specific code organization, and inline styles. Leverages Expo SDK 52+ features, React Navigation v7, and Reanimated for smooth 60fps animations.

Refactor React and TypeScript code to improve maintainability, readability, and performance. This skill transforms complex React components into clean, well-structured code following modern React 19 patterns. It addresses component bloat, prop drilling, unnecessary re-renders, and improper hook usage. Leverages React 19 features including the React Compiler for automatic memoization, Actions for form handling, useOptimistic for immediate UI feedback, the use() hook for async data, and Server Components for optimal performance.

Refactor Scikit-learn and machine learning code to improve maintainability, reproducibility, and adherence to best practices. This skill transforms working ML code into production-ready pipelines that prevent data leakage and ensure reproducible results. It addresses preprocessing outside pipelines, missing random_state parameters, improper cross-validation, and custom transformers not following sklearn API conventions. Implements proper Pipeline and ColumnTransformer patterns, systematic hyperparameter tuning, and appropriate evaluation metrics.

Refactor Spring Boot and Java code to improve maintainability, readability, and adherence to enterprise best practices. This skill transforms messy Spring Boot applications into clean, well-structured solutions following SOLID principles and Spring Boot 3.x conventions. It addresses fat controllers, improper transaction boundaries, field injection anti-patterns, and scattered configuration. Leverages Java 21+ features including record patterns, pattern matching for switch, virtual threads, and sequenced collections.