Jeep cherokee belt/pulley squeel

I have an intermittent belt screech on startup. Comes and goes. I’m thinking it’s the idler/tensioner pulley, but not sure.

Anyone have this problem or knows a way to identify the source?

How old are the belts?

What you’re probably hearing is the belt that drives the alternator slipping when the engine is started. When rubber belts are cold they expand. When you start the engine, the starter draws a lot of current from the battery. When the engine starts, the alternator comes on line immediately to recharge the depleted battery that was used to operate the starter. This causes a load from alternator to the engine to where the belt slips for a second or two and you get the squeal then it stops.