No need to make up hypotheticals. The server isn't the final destination for your LLM requests. The reply needs to come back to you.
If Bob and Alice are in an E2EE chat Bob and Alice are the ends. Even if Bob asks Alice a question and she replies back to Bob, Alice is still an end.
Similarly with AI. The AI is one of the ends of the conversation.
If Bob and Alice are in an E2EE chat Bob and Alice are the ends. Even if Bob asks Alice a question and she replies back to Bob, Alice is still an end.
Similarly with AI. The AI is one of the ends of the conversation.