dotnet-best-practices
Ensure .NET/C# code meets best practices for the solution/project.
Summary
- Purpose
- Helps align .NET/C# code with a solution's practices for documentation, architecture, dependency injection, async work, testing, configuration, localization, logging, security, and maintainability.
- When to use
- Apply it during implementation or review of .NET/C# changes involving services, tests, configuration, async work, error handling, or other project conventions.
- Outputs
- The resulting code follows applicable project practices for documentation, design, services, testing, configuration, async operations, logging, security, and resource handling.
Upstream changes (3, latest included 2026-02-19)
caab1f6 Convert all prompts to skills and update plugin manifests Adds a .NET/C# best-practices skill covering documentation, architecture, dependency injection, localization, async, testing, configuration, Semantic Kernel, error handling, security, and code quality. 2f9c96d Fix deprecated 'mode' attribute in prompt files by renaming to 'agent' (#441) Renames the prompt front-matter field from `mode` to `agent`, retaining the value `agent`. e1c7c7a Add 18 new prompts files (#56) Adds a .NET/C# best-practices prompt covering documentation, architecture, dependency injection, localization, async, testing, configuration, Semantic Kernel, error handling, security, and code quality. npx skills add "lettucebo/Skills#v2.2.0@dotnet-best-practices" --full-depth ⚠ Available after v2.2.0 is published
.NET/C# Best Practices
Your task is to ensure .NET/C# code in ${selection} meets the best practices specific to this solution/project. This includes:
Documentation & Structure
- Create comprehensive XML documentation comments for all public classes, interfaces, methods, and properties
- Include parameter descriptions and return value descriptions in XML comments
- Follow the established namespace structure: {Core|Console|App|Service}.{Feature}
Design Patterns & Architecture
- Use primary constructor syntax for dependency injection (e.g.,
public class MyClass(IDependency dependency)) - Implement the Command Handler pattern with generic base classes (e.g.,
CommandHandler<TOptions>) - Use interface segregation with clear naming conventions (prefix interfaces with 'I')
- Follow the Factory pattern for complex object creation.
Dependency Injection & Services
- Use constructor dependency injection with null checks via ArgumentNullException
- Register services with appropriate lifetimes (Singleton, Scoped, Transient)
- Use Microsoft.Extensions.DependencyInjection patterns
- Implement service interfaces for testability
Resource Management & Localization
- Use ResourceManager for localized messages and error strings
- Separate LogMessages and ErrorMessages resource files
- Access resources via
_resourceManager.GetString("MessageKey")
Async/Await Patterns
- Use async/await for all I/O operations and long-running tasks
- Return Task or Task from async methods
- Use ConfigureAwait(false) where appropriate
- Handle async exceptions properly
Testing Standards
- Use MSTest framework with FluentAssertions for assertions
- Follow AAA pattern (Arrange, Act, Assert)
- Use Moq for mocking dependencies
- Test both success and failure scenarios
- Include null parameter validation tests
Configuration & Settings
- Use strongly-typed configuration classes with data annotations
- Implement validation attributes (Required, NotEmptyOrWhitespace)
- Use IConfiguration binding for settings
- Support appsettings.json configuration files
Semantic Kernel & AI Integration
- Use Microsoft.SemanticKernel for AI operations
- Implement proper kernel configuration and service registration
- Handle AI model settings (ChatCompletion, Embedding, etc.)
- Use structured output patterns for reliable AI responses
Error Handling & Logging
- Use structured logging with Microsoft.Extensions.Logging
- Include scoped logging with meaningful context
- Throw specific exceptions with descriptive messages
- Use try-catch blocks for expected failure scenarios
Performance & Security
- Use C# 12+ features and .NET 8 optimizations where applicable
- Implement proper input validation and sanitization
- Use parameterized queries for database operations
- Follow secure coding practices for AI/ML operations
Code Quality
- Ensure SOLID principles compliance
- Avoid code duplication through base classes and utilities
- Use meaningful names that reflect domain concepts
- Keep methods focused and cohesive
- Implement proper disposal patterns for resources