dotnet

name	dotnet
description	Core guidelines for writing C# 14 and .NET 10 code in the planthor-backend project.

.NET 10 & C# 14 Development Guidelines

You are an expert .NET software architect working on planthor-backend.

Core Language Rules

• Modern C#: Always use the latest C# 14 / .NET 10 features.
• Primary Constructors: Use primary constructors for dependency injection in classes instead of explicit constructor bodies.
• Nullability: Nullable reference types are enabled. Treat all compiler warnings as errors. Use ? appropriately and avoid ! (null-forgiving operator) unless absolutely necessary.
• Collection Expressions: Use [] instead of new List<T>() or Array.Empty<T>().
• Async/Await: All I/O operations MUST be asynchronous. Suffix methods with Async and ALWAYS pass CancellationToken cancellationToken.

Documentation & XML Comments

• Mandatory Documentation: ALL public-facing components (classes, interfaces, methods, properties, records, and primary constructors) MUST have dedicated XML comments.
• Standards: Use standard tags (<summary>, <param>, <returns>, <remarks>, <exception>). The comments must be descriptive, clearly explaining the why and the what, not just restating the method name.
• OpenAPI & Scalar: For API controllers, use these XML comments in combination with [ProducesResponseType] and relevant OpenAPI attributes. Ensure all XML documentation is fully compatible with Scalar (Scalar.AspNetCore) for beautiful, modern API reference generation.

Clean Architecture & MediatR Rules

• API Layer: Use API Controllers (inheriting from ControllerBase and decorated with [ApiController]) in the src/Api/Controllers directory. The controller should ONLY dispatch requests via MediatR (e.g., _sender.Send(command)). Do not put business logic in endpoints.
• Application Layer: Contains MediatR IRequestHandler implementations. This layer defines interfaces (e.g., IRepository) but NEVER implements them.
• Domain Layer: Contains pure C# entities, value objects, and domain events. NEVER reference Entity Framework, UI, or external packages here.
• Infrastructure Layer: Implements data access (EF Core) and external services.

Prohibited Patterns

• NEVER inject DbContext directly into a MediatR handler or API endpoint. Use the Repository pattern.
• NEVER use DateTime.Now. Use TimeProvider.System for testability.