Loop your assistant into any conversation.
Copy it on an email to have it follow along, or forward one to ask for help. Either way, it only ever replies to you.
Copy it in to watch
Add your assistant to the cc line and it follows the conversation from there, keeping track of what is open and what has gone quiet.
Forward it to ask
Forward any email with a question and your assistant replies with the answer, a draft, or a summary.
It only ever replies to you
Your assistant never messages the other people on the conversation. What it finds goes to your inbox alone, and you decide what goes out.
Bring it into the conversation.
Copy your assistant on the next conversation you do not want to babysit.