claude-craftkit

Backend engineering with Modular Monolith, bounded contexts, and Hono. **ALWAYS use when implementing ANY backend code within contexts, Hono APIs, HTTP routes, or service layer logic.** Use proactively for context isolation, minimal shared kernel, and API design. Examples - "create API in context", "implement repository", "add use case", "context structure", "Hono route", "API endpoint", "context communication", "DI container".

Clean Architecture principles for Modular Monolith with bounded contexts and minimal shared kernel. **ALWAYS use when working on backend code, ESPECIALLY when creating files, deciding file locations, or organizing contexts (auth, tax, bi, production).** Use proactively to ensure context isolation and prevent "Core Obesity Syndrome". Examples - "create entity", "add repository", "where should this file go", "modular monolith", "bounded context", "shared kernel", "context isolation", "file location", "layer organization".

Expert in code design standards including SOLID principles, Clean Code patterns (KISS, YAGNI, DRY, TDA), and pragmatic software design. **ALWAYS use when designing ANY classes/modules, implementing features, fixing bugs, refactoring code, or writing functions.** Use proactively to ensure proper design, separation of concerns, simplicity, and maintainability. Examples - "create class", "design module", "implement feature", "refactor code", "fix bug", "is this too complex", "apply SOLID", "keep it simple", "avoid over-engineering".

Error handling patterns including exceptions, Result pattern, validation strategies, retry logic, and circuit breakers. **ALWAYS use when implementing error handling in backend code, APIs, use cases, or validation logic.** Use proactively for robust error handling, recovery mechanisms, and failure scenarios. Examples - "handle errors", "Result pattern", "throw exception", "validate input", "error recovery", "retry logic", "circuit breaker", "exception hierarchy".

Expert frontend engineering with simplified pragmatic architecture, React 19, TanStack ecosystem, and Zustand state management. **ALWAYS use when implementing ANY frontend features.** Use when setting up project structure, creating pages and state management, designing gateway injection patterns, setting up HTTP communication and routing, organizing feature modules, or optimizing performance. **ALWAYS use when implementing Gateway Pattern (Interface + HTTP + Fake), Context API injection, Zustand stores, TanStack Router, or feature-based architecture.**

Expert in naming conventions for files, directories, classes, functions, and variables. **ALWAYS use when creating ANY files, folders, classes, functions, or variables, OR when renaming any code elements.** Use proactively to ensure consistent, readable naming across the codebase. Examples - "create new component", "create file", "create folder", "name this function", "rename function", "rename file", "rename class", "refactor variable names", "review naming conventions".

Development workflow and quality gates for the Bun + TypeScript stack. **ALWAYS use before commits** to ensure quality gates are met. Also use when starting development or when user asks about workflow process. Examples - "before commit", "quality gates", "workflow checklist", "bun commands", "pre-commit checks".

TypeScript type safety including type guards and advanced type system features. **ALWAYS use when writing ANY TypeScript code (frontend AND backend)** to ensure strict type safety, avoid `any` types, and leverage the type system. Examples - "create function", "implement class", "define interface", "type guard", "discriminated union", "type narrowing", "conditional types", "handle unknown types".