Add CQRS Query

When the user asks to add a new query, scaffold the following files in the correct microservice. Ask which service if ambiguous.

Arguments

• {Name} — Query name in PascalCase (e.g., GetDeviceById, ListBundles)
• {Service} — Target microservice (e.g., DeviceManager, BundleOrchestrator). Ask if ambiguous.

Prerequisites

• The target microservice must exist under src/
• The entity and its query repository interface should exist (if not, run /add-entity first)
• An Endpoints file should exist at Host/Endpoints/ (if not, create one)

1. Query Record (Application/Queries/{QueryName}.cs)

namespace SignalBeam.{Service}.Application.Queries;

public record {Name}Query({parameters});

For list queries, include pagination:

public record List{Entity}Query(Guid TenantId, int PageNumber = 1, int PageSize = 20, string? Search = null);

2. Response Record (Application/Contracts/)

For single entity:

public record {Name}Response({fields});

For lists, return paged response:

public record {Name}ListResponse(IReadOnlyCollection<{Name}Response> Items, int TotalCount, int PageNumber, int PageSize);

3. Handler (Application/Queries/{Name}Handler.cs)

namespace SignalBeam.{Service}.Application.Queries;

public class {Name}Handler
{
    private readonly I{Entity}QueryRepository _queryRepository;

    public {Name}Handler(I{Entity}QueryRepository queryRepository)
    {
        _queryRepository = queryRepository;
    }

    public async Task<Result<{Name}Response>> Handle({Name}Query query, CancellationToken cancellationToken)
    {
        // Use query repository (read-optimized, potentially Dapper)
        // Return Result.Success or Result.Failure("NOT_FOUND", ...)
    }
}

4. Query Repository Method

Add to the query repository interface in Domain:

Task<{Entity}?> GetByIdAsync({Entity}Id id, CancellationToken cancellationToken = default);

Implement in Infrastructure using EF Core or Dapper for read-optimized queries.

5. Endpoint (add to existing Host/Endpoints/{Domain}Endpoints.cs)

group.MapGet("/{route}", {Name})
    .WithName("{Name}")
    .WithSummary("...")
    .Produces<{Name}Response>(StatusCodes.Status200OK)
    .ProducesProblem(StatusCodes.Status404NotFound);

private static async Task<IResult> {Name}(
    [FromRoute] Guid id,
    [FromServices] {Name}Handler handler,
    CancellationToken cancellationToken)
{
    var query = new {Name}Query(id);
    var result = await handler.Handle(query, cancellationToken);
    return result.ToHttpResult();
}

For list endpoints, use [FromQuery] for pagination:

[FromQuery] int pageNumber = 1, [FromQuery] int pageSize = 20, [FromQuery] string? search = null

Checklist

• Query record is immutable
• Uses query repository (read side), not command repository
• Handler returns Result<T>
• Endpoint has OpenAPI metadata
• Pagination supported for list queries
• CancellationToken propagated

Output

After scaffolding, report:

## Scaffolded: {Name}Query

Files created/modified:
- `src/{Service}/{Service}.Application/Queries/{Name}Query.cs`
- `src/{Service}/{Service}.Application/Queries/{Name}Handler.cs`
- `src/{Service}/{Service}.Application/Contracts/{Name}Response.cs`
- `src/{Service}/{Service}.Host/Endpoints/{Domain}Endpoints.cs` (modified)

Next: Run `/run-tests` to verify, or `/add-feature` to create the frontend calling this query.

Error Handling

• Endpoints file doesn't exist: Create a new {Domain}Endpoints.cs with the route group boilerplate.
• Query repository interface missing: Create it in the Domain layer alongside the command repository.
• Entity doesn't exist: Suggest running /add-entity first before proceeding.

Related Skills

• /add-command if you also need a write endpoint for the same resource
• /add-entity if the entity doesn't exist yet
• /add-feature to create the frontend feature that calls this query