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csharp-best-practices skill

/skills/csharp-best-practices

This skill provides up-to-date C# 12 and .NET 8 best-practice guidelines to reference during code writing, injecting guidance before coding.

npx playbooks add skill jeongheonk/c-sharp-custom-marketplace --skill csharp-best-practices

Review the files below or copy the command above to add this skill to your agents.

Files (13)
SKILL.md
2.9 KB
---
name: csharp-best-practices
description: C# 12 / .NET 8 기준 코드 작성 가이드라인. 코드 작성 전/중에 참조하는 knowledge-base skill. Modern C# 기능과 베스트 프랙티스를 자동 주입.
user-invocable: true
context: current
argument-hint: "[topic]"
allowed-tools:
  - Read
  - Glob
  - Grep
---

# C# Best Practices

C# 12 / .NET 8 기준 코드 작성 가이드라인 knowledge-base skill.

## Overview

이 스킬은 코드 **작성 시** 참조하는 가이드라인을 제공합니다. 코드 리뷰(csharp-code-review)와 달리, 작성 전/중에 올바른 패턴을 안내합니다.

| 구분 | csharp-code-review | csharp-best-practices |
|------|-------------------|----------------------|
| 목적 | 기존 코드 리뷰/검토 | 코드 작성 시 가이드라인 참조 |
| 시점 | 코드 작성 후 | 코드 작성 전/중 |
| 출력 | 리뷰 리포트 | 가이드라인 주입 |

## Arguments

- `$ARGUMENTS[0]`: 조회할 토픽 (optional)
  - 미지정 시 전체 규칙 목록 표시
  - 예: `primary-constructor`, `record`, `pattern-matching`

## Rules

### C# 12 Features (.NET 8) — CRITICAL

코드 작성 시 반드시 고려해야 할 C# 12 기능:

| 규칙 | 파일 | 설명 |
|------|------|------|
| Primary Constructors | `rules/cs12-primary-constructor.md` | class/struct 직접 생성자 매개변수 |
| Collection Expressions | `rules/cs12-collection-expression.md` | `[1, 2, 3]` 통합 구문 |
| Alias Any Type | `rules/cs12-alias-any-type.md` | `using` alias 모든 타입 |
| Lambda Default Params | `rules/cs12-lambda-defaults.md` | 람다 기본 매개변수 |
| Inline Arrays | `rules/cs12-inline-array.md` | struct 고정 크기 배열 |
| ref readonly Parameters | `rules/cs12-ref-readonly-param.md` | ref/in 명확한 API |

### Modern C# (C# 9-11, .NET 8 호환) — MEDIUM

| 규칙 | 파일 | 버전 |
|------|------|------|
| Record Types | `rules/modern-record-type.md` | C# 9 |
| required / init | `rules/modern-required-init.md` | C# 11 |
| Pattern Matching | `rules/modern-pattern-matching.md` | C# 8-11 |
| List Patterns | `rules/modern-list-pattern.md` | C# 11 |
| Raw String Literals | `rules/modern-raw-string-literal.md` | C# 11 |
| File-scoped Namespaces | `rules/modern-file-scoped-namespace.md` | C# 10 |

## Execution

### 토픽 지정 시

해당 규칙 파일을 읽고 가이드라인을 출력합니다.

```
/csharp-best-practices primary-constructor
→ rules/cs12-primary-constructor.md 내용 출력
```

### 토픽 미지정 시

전체 규칙 목록을 요약하여 출력합니다.

```
/csharp-best-practices
→ 12개 규칙 목록 + 간단 설명 출력
```

## 현재 전달받은 인자

**ARGUMENTS**: $ARGUMENTS

## 실행 지시

1. ARGUMENTS가 있으면 해당 토픽과 매칭되는 규칙 파일을 찾아 내용을 출력하세요.
2. ARGUMENTS가 비어있으면 전체 규칙 목록을 요약하여 출력하세요.
3. 규칙 출력 시 **Before/After 코드 예시**를 반드시 포함하세요.

Overview

This skill provides C# 12 / .NET 8 coding guidelines to consult while writing code. It injects modern language features and practical patterns so you apply up-to-date idioms during design and implementation. Use it as an in-line knowledge base that favors preventive guidance over post-hoc review.

How this skill works

When asked for a specific topic, the skill locates the matching rule file and returns a concise guideline with Before/After code examples. If no topic is provided, it summarizes the full ruleset for quick scanning. The content emphasizes C# 12 features (primary constructors, collection expressions, alias any type, lambda defaults, inline arrays, ref readonly parameters) and compatible modern C# practices.

When to use it

  • Before starting a new class, struct, or API design to pick idiomatic constructs
  • While implementing features to prefer modern, safer syntactic forms
  • To learn or enforce C# 12 features in a .NET 8 codebase
  • When preparing code for review to reduce common style and API mistakes
  • To generate quick Before/After examples for teaching or documentation

Best practices

  • Prefer primary constructors for simple immutable data containers to reduce boilerplate
  • Use collection expressions and inline arrays where readability and allocation patterns improve
  • Adopt 'alias any type' where obvious aliases reduce noise and improve intent
  • Mark parameters ref readonly (in/ref) when avoiding copies on large structs
  • Leverage modern pattern matching, records, required/init and file-scoped namespaces for clarity

Example use cases

  • Request 'primary-constructor' to get a rule with Before/After examples showing constructor reduction
  • Ask for 'collection-expression' to learn replacing verbose initializers with [a, b, c] syntax
  • Summarize all rules to create a team’s lightweight C# 12 checklist for pull requests
  • Embed guidelines in an IDE snippet or pre-commit hook to nudge developers toward modern patterns
  • Produce documentation examples demonstrating ref readonly parameter usage for performance

FAQ

What happens if I don't provide a topic?

The skill returns a summarized list of all rules with short descriptions and suggested uses.

Will I get code examples?

Yes. Every rule response includes Before/After code examples illustrating the recommended change.