I have been using the builtin macOS `caffeinate` command for this.
For example:
caffeinate -dimsu
That keeps the Mac awake so I can use Claude remotely from phone.
You can also wrap your command as well, but I rarely use it.
caffeinate -dimsu your-agent-command
Caffeinate is burned into my muscle memory at this point. I attribute that to the realization that you could repeat opt flags. There's something catchy about
caffeinate -dimsum