common-best-practices

Apply Guard, Value Types, Immutability, and Naming conventions in Swift. Use when writing idiomatic Swift using guard, value types, immutability, or naming conventions. (triggers: **/*.swift, guard, let, struct, final)

Apply core coding standards, dependency injection, and configuration for Spring Boot 3. Use when applying Spring Boot 3 coding standards or configuring dependency injection. (triggers: application.properties, **/*Service.java, autowired, requiredargsconstructor, configuration-properties, slf4j)

Write PHP following best practices, PSR standards, and code quality guidelines. Use when writing PHP following PSR standards, SOLID principles, or improving code quality. (triggers: **/*.php, psr-12, camelCase, PascalCase, dry, solid)

Core patterns for robust Kotlin code including scope functions and backing properties. Use when writing idiomatic Kotlin, choosing between scope functions (let/apply/run/also/with), encapsulating mutable state with backing properties, or exposing read-only collection interfaces. (triggers: **/*.kt, apply, let, run, also, with, runCatching, backing property, MutableList, internal, private set)

Idiomatic JavaScript patterns and conventions for maintainable code. Use when writing or refactoring JavaScript following idiomatic patterns and conventions. (triggers: **/*.js, **/*.mjs, module, import, export, error, validation)

Apply core Effective Java patterns for robust, maintainable code. Use when applying SOLID principles, choosing between inheritance and composition, refactoring Java code smells, or reviewing class design. (triggers: **/*.java, refactor, SOLID, builder, factory, composition, immutable, Optional, checked exception, clean code)

Dart code quality conventions: naming, const/final/var hierarchy, single quotes, trailing commas, collection idioms, tear-offs, and import organization. Use when writing new Dart code or reviewing for style violations — wrong import style, global variables, var misuse, anonymous lambdas where tear-offs fit, or missing trailing commas. (triggers: **/*.dart, naming, convention, trailing comma, import, tear-off)

Enforce structured JSON logging, OpenTelemetry distributed tracing, and RED metrics across backend services. Use when adding request correlation, setting up tracing spans, defining SLO burn-rate alerts, or instrumenting middleware. (triggers: **/*.service.ts, **/*.handler.ts, **/*.middleware.ts, **/*.interceptor.ts, **/*.go, **/*.java, **/*.kt, **/*.py, logging, tracing, metrics, opentelemetry, observability, slo)

Enforce universal mobile UX principles for touch-first interfaces including touch targets, safe areas, and mobile-specific interaction patterns. Use when building mobile screens, handling touch interactions, or validating safe area compliance. (triggers: **/*_page.dart, **/*_screen.dart, **/*_view.dart, **/*.swift, **/*Activity.kt, **/*Screen.tsx, mobile, responsive, SafeArea, touch, gesture, viewport)

Apply motion design principles for mobile apps covering timing curves, transitions, gestures, and performance-conscious animations. Use when implementing screen transitions, gesture-driven interactions, shared-element animations, or optimizing animation frame rates on iOS, Android, or Flutter. (triggers: **/*_page.dart, **/*_screen.dart, **/*.swift, **/*Activity.kt, **/*Screen.tsx, Animation, AnimationController, Animated, MotionLayout, transition, gesture)

Cross-cutting standards for error design, response shapes, error codes, and boundary placement across API, domain, and infrastructure layers. Use when defining error hierarchies, wrapping exceptions, building standardized error responses, or placing error boundaries in layered architectures. (triggers: **/*.service.ts, **/*.handler.ts, **/*.controller.ts, **/*.go, **/*.java, **/*.kt, **/*.py, error handling, exception, try catch, error boundary, error response, error code, throw)

Standards for creating clear, audience-appropriate C4 and UML architecture diagrams with Mermaid. Use when producing system context diagrams, container views, sequence diagrams, or updating ARCHITECTURE.md files. (triggers: ARCHITECTURE.md, **/*.mermaid, **/*.drawio, diagram, architecture, c4, system design, mermaid)