dotnet-core-expert Checked

Use when building .NET 8 applications with minimal APIs, clean architecture, or cloud-native microservices. Invoke for Entity Framework Core, CQRS with MediatR, JWT authentication, AOT compilation.

.NET Core Expert

Use when building .NET 8 applications with minimal APIs, clean architecture, or cloud-native microservices. Invoke for Entity Framework Core, CQRS with MediatR, JWT authentication, AOT compilation.

.NET Core Expert

Core Workflow

1. **Analyze requirements** — Identify architecture pattern, data models, API design

2. **Design solution** — Create clean architecture layers with proper separation

3. **Implement** — Write high-performance code with modern C# features; run dotnet build to verify compilation — if build fails, review errors, fix issues, and rebuild before proceeding

4. **Secure** — Add authentication, authorization, and security best practices

5. **Test** — Write comprehensive tests with xUnit and integration testing; run dotnet test to confirm all tests pass — if tests fail, diagnose failures, fix the implementation, and re-run before continuing; verify endpoints with curl or a REST client

Reference Guide

Load detailed guidance based on context:

| Topic | Reference | Load When |

|-------|-----------|-----------|

| Minimal APIs | references/minimal-apis.md | Creating endpoints, routing, middleware |

| Clean Architecture | references/clean-architecture.md | CQRS, MediatR, layers, DI patterns |

| Entity Framework | references/entity-framework.md | DbContext, migrations, relationships |

| Authentication | references/authentication.md | JWT, Identity, authorization policies |

| Cloud-Native | references/cloud-native.md | Docker, health checks, configuration |

Constraints

### MUST DO

• Use .NET 8 and C# 12 features
• Enable nullable reference types: <Nullable>enable</Nullable> in the .csproj
• Use async/await for all I/O operations — e.g., await dbContext.Users.ToListAsync()
• Implement proper dependency injection
• Use record types for DTOs — e.g., public record UserDto(int Id, string Name);
• Follow clean architecture principles
• Write integration tests with WebApplicationFactory<Program>
• Configure OpenAPI/Swagger documentation

### MUST NOT DO

• Use synchronous I/O operations
• Expose entities directly in API responses
• Skip input validation
• Use legacy .NET Framework patterns
• Mix concerns across architectural layers
• Use deprecated EF Core patterns

Code Examples

### Minimal API Endpoint

// Program.cs
var builder = WebApplication.CreateBuilder(args);
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
builder.Services.AddMediatR(cfg => cfg.RegisterServicesFromAssembly(typeof(Program).Assembly));

var app = builder.Build();
app.UseSwagger();
app.UseSwaggerUI();

app.MapGet("/users/{id}", async (int id, ISender sender, CancellationToken ct) =>
{
    var result = await sender.Send(new GetUserQuery(id), ct);
    return result is null ? Results.NotFound() : Results.Ok(result);
})
.WithName("GetUser")
.Produces<UserDto>()
.ProducesProblem(404);

app.Run();