The PushNotification/desktop notification tool now provides a specific reason when a notification is suppressed because the terminal is active:
"Not sent — this terminal is active, so your output here already reaches the user; a separate notification would be redundant."
Previously the tool returned a less specific "Not sent — terminal has focus" message.
Evidence
(search for "Not sent — this terminal is active, so your output here already reaches the user")
Strings lifted out of the shipped bundle, so the claim above can be checked against them.