A companion who remembers you
Talk to it like you'd message a friend. It remembers what matters to you, keeps track of things for you, and reminds you right on time, in its own voice.
Remembers you
Your name, your people, what you're going through. Say it once and it remembers, and you can always see and edit what it knows.
Keeps things for you
Ask it to note something down or look something up. It runs the errand and tells you how it went.
On time, in its voice
"Remind me at 8 tomorrow" becomes a notification at 8, written by your companion. Once, never twice.
One long conversation, one companion who stays the same person.