on idle not starting

I never worked with on idle so it may be a dumb question, apologies in advance. When I run the following script as script or as program it will never initiate the on idle command. Is there anything I need to do?

on run
	say "start"
end run

on idle
	say "repeat"
	return 10
end idle

When you saved it as an application did you select “Stay Open”?

I’ve actually never used a idle handler, but that would be my guess.

That was it!