C5 proved you could call Claude from C#. A single request/response is fine for short answers, but it has two limits: the user stares at a spinner until the whole reply lands, and the model can only talk — it can't do anything to your data. C6 fixes both. Streaming surfaces tokens as they're generated, and a tool-calling agent loop lets Claude search the catalog and update reading progress by calling your existing Core services. No new packages — you're still on the Anthropic SDK from C5, and your Anthropic API key is already in user-secrets.
