Start here. This is the direct spoken answer to practice first.
Overview
A conversation identifier is not permission to send an entire history back to a model forever.
The application owns the conversation, participants, messages, tool outcomes, and business state in a durable store. For each turn it builds a bounded model context from the relevant history, current policy, and trusted state. The provider's conversation feature can simplify transport, but it does not replace application authorization, retention, or an auditable record.