How do you remove the supply of stolen tools?

In prison Architect how do you remove the supply of stolen tools?

I assume you are trying to complete a grant, if so it's good to get this one out the way before your prison becomes too large.

The most important things it to put metal detectors in workshop doorways, after that additional metal detectors at other busy locations (e.g. canteen) will help.

Make sure contraband cannot be thrown over the fence and perform nightly shakedowns to find tools hidden in cells or smuggled in. Keep up the searches for a few days in a row and you should be able to get the supply to zero.