Decorator pattern for CQRS handlers adds authorization and telemetry in .NET

The article shows how to add authorization and telemetry around CQRS handlers in .NET without using MediatR, relying on Dependency Injection and OpenTelemetry. It explains that the Decorator pattern lets each layer wrap a handler behind the same interface, so callers need not know how many layers exist. A pizzeria internal tool example illustrates the need: checking a user's permissions, measuring execution time, and recording success or failure. The author distinguishes queries, which read or compute data, from commands, which change state, and notes that CQRS does not require MediatR. The piece targets ASP.NET Core projects on .NET 10 and includes tests to verify the decorator chain works.