Instruction file imported from am-space/own-planner (.github/instructions/backend.instructions.md). Copyright stays with the author.

Backend Instructions

Technology

• Use C# for server-side changes.
• Target .NET 10 and align with the existing code style in the edited project.
• Preserve nullability annotations and existing async APIs.

Coding rules

• Prefer async/await for I/O and service operations.
• Preserve cancellation token flow where applicable.
• Use dependency injection instead of direct construction when wiring services.
• Validate public method arguments early.
• Preserve structured logging patterns based on ILogger<T> and message templates.
• Avoid sync-over-async unless there is already an established pattern and it cannot be changed safely.
• Dispose async resources safely.

Layering rules

• Keep domain logic in OwnPlanner.Domain.
• Keep application orchestration, use-cases, and DTO mapping in OwnPlanner.Application.
• Keep database, filesystem, external API, and adapter concerns in OwnPlanner.Infrastructure.
• Keep HTTP, authentication, and presentation concerns in OwnPlanner.Web.Server.
• Do not move infrastructure concerns into domain or application layers.

Web server guidance

• Follow existing ASP.NET Core patterns for controllers, services, and registration.
• Preserve authentication and user-isolation behavior.
• When modifying chat-related services, preserve session behavior, async disposal, and structured logs.
• Prefer extending existing services instead of duplicating cross-cutting logic.

Change preferences

• Favor small, readable changes over broad refactors.
• Keep public APIs stable unless the task explicitly requires a contract change.
• When editing existing files, match their formatting and local conventions.