What problem does it solve? Building message-driven .NET services requires consistent patterns for receiving commands and events from a broker, validating payloads, handling errors, and delegating to application logic. This Skill guides you through adding or modifying subscribers in a CoreEx Subscribe host so each subscriber stays a thin routing layer with no embedded business logic. ## Core Features & Use Cases - Three Subscriber Scenarios: Distinguishes command subscribers (delegate to application services), event data-sync subscribers (delegate to IXxxSyncAdapter replication adapters), and event business-process subscribers (choreography steps delegating to application services). - Typed and Untyped Subscribers: Covers SubscribedBase for key-only messages and SubscribedBase<TValue> with ValueValidator for payload-carrying messages, plus subject naming conventions with payload-driven .v{n} version suffixes. - Error Handling and Saga Guidance: Configures shared static ErrorHandler instances for graceful not-found and retry/dead-letter control, and explains choreography-based saga design with idempotency and compensation rules. - Use Case: You need to react to a product.updated event from another domain and keep a local cached copy. The Skill produces a typed ModifySubscriber with a ValueValidator that delegates to your sync adapter, with no Program.cs changes required thanks to AddSubscribersUsing discovery. ## Quick Start Ask the AI to add a CoreEx subscriber for a given scenario, subject, and payload type, for example: create a typed event data-sync subscriber for the subject contoso.products.product.updated.v1 that validates the payload and delegates to IProductSyncAdapter.
