Learn How I Talk now says how much mail a run will touch before it reads a message, and a second run over the same mailbox reads only what arrived since the first.
The number comes before the reading
The first search returns how many messages the window holds, and the run says so in one line. On Personal nothing is charged to GBrain, because the run spends the AI’s own plan. Asking for everything still asks before the larger job.
A second run reads new mail, not the mailbox
The workspace keeps a checkpoint for each connected account and each search: the day that search reached. A later run starts from that day, so it lists what arrived since and skips every thread already read. A morning habit reads one page of new mail instead of the whole mailbox again.
What you might notice
A run with nothing new finishes in seconds. Stopping is safe at any point, because the checkpoint on disk holds the place. One conversation is read once, so a thread that picks up again is not read again by itself.
What you need to do
Nothing, if a workspace already runs the skill. To start, connect an AI with Read & Write and paste the prompt on Email, read once and kept current.