Each tool stops after a set number of calls a day against one application. The count resets daily.
The limit protects the application, not the assistant. Every client reaching your mail draws from the same number, so one assistant cannot spend another’s allowance without you seeing it.
Where to find one
Open the client, then Limits, or the application, then Limits. Both show the same numbers from a different side: what this client used today, or what the account has left across every client reaching it.
An assistant that hits a limit will hand you the link to that exact page, so you usually arrive here already knowing which one.
The two ways to change it
Add room for today is temporary. It is gone when the day resets, and the standing number comes back. Use it to unblock something now.
Change the daily limit is the standing number, every day from now on. Leave it empty to go back to ours.
Both are yours alone. An assistant can read its allowance and tell you it ran out; it cannot raise it.
What “paused” means
A tool at its limit is paused, not broken. Everything else that application can do keeps working, and the paused tool starts again when the day resets.