Conversation.ExternalID of the session's conversation — the signed per-session scope id for an
anonymous guest. null/undefined when the conversation has none (a named user's session) or
could not be loaded.
OptionalConversationTrue when the conversation was loaded under the CALLER's identity (so its row-level security allowed
the read). Only consulted for a named principal with a resource scope on a conversation that carries
no ExternalID; omitted means unknown and is treated as unreadable (fail closed).
AIAgentSession.UserID.
What the decision needs to know about the session.