Swe

---
name: swe
description: Applies software engineering best practices, design principles, and avoids common anti-patterns. Use when designing systems, reviewing code quality, refactoring legacy code, making architectural decisions, or improving maintainability.
---

# Software Engineering Best Practices

A comprehensive guide to writing maintainable, scalable, and high-quality software, organized by development phase.

## Phases

| Phase          | File                                     | Content                                                                        |
| -------------- | ---------------------------------------- | ------------------------------------------------------------------------------ |
| Design         | [design.md](./references/design.md)                 | Requirements, principles, architecture, security by design                     |
| Implementation | [implementation.md](./references/implementation.md) | Self-documenting code, naming, functions, error handling, linting, code smells |
| Testing        | [testing.md](./references/testing.md)               | Test pyramid, BDD, test quality, anti-patterns                                 |
| Review         | [review.md](./references/review.md)                 | Code review checklist, self-review before PR                                   |
| Maintenance    | [maintenance.md](./references/maintenance.md)       | Refactoring, technical debt, performance, documentation                        |

## Key Principles Summary

- **Simplicity wins**: Write the simplest code that works; add complexity only when required
- **Single responsibility**: Each function/class/module should do one thing well
- **Self-documenting code**: Code should explain itself; comments are a code smell
- **Fail fast**: Validate inputs early, let unexpected errors propagate
- **Test behavior**: Focus on what code does, not implementation details
- **No backwards compatibility**: Don't add legacy support unless explicitly requested
- **Consistency**: Match existing project conventions over personal preference

## Related Skills and Tools

This skill integrates with other available tools for practical implementation:

| Task                       | Skill/Tool                           | Usage                                                              |
| -------------------------- | ------------------------------------ | ------------------------------------------------------------------ |
| **Code Analysis**          | [codemapper](../codemapper/SKILL.md) | Map codebase structure, trace call paths, find callers/callees     |
| **Structural Refactoring** | [ast-grep](../ast-grep/SKILL.md)     | Search/replace code patterns using AST, safe automated refactoring |
| **Duplicate Detection**    | [jscpd](../jscpd/SKILL.md)           | Find copy-pasted code blocks across files                          |
| **Dead Code Detection**    | [knip](../knip/SKILL.md)             | Find unused dependencies, files, and exports                       |
| **Testing**                | [vitest](../vitest/SKILL.md)         | Write and run tests, mocking, coverage reports                     |
| **Type Safety**            | [typescript](../typescript/SKILL.md) | Type definitions, generics, type guards                            |
| **Python Quality**         | [python](../python/SKILL.md)         | pytest, ruff, mypy for Python projects                             |
| **Version Control**        | [jujutsu](../jujutsu/SKILL.md)       | Track changes, rebase, manage commits                              |
| **Code Review**            | [gh](../gh/SKILL.md)                 | Create PRs, manage issues, review workflow                         |
| **Package Management**     | [bun](../bun/SKILL.md)               | Install dependencies, run scripts, bundle code                     |