The All-Purpose Tool is a spellcasting focus for artificers printed in Tasha's. Among other things, it has the following property:
As an action, you can focus on the tool to channel your creative forces. Choose a cantrip that you don't know from any class list. For 8 hours, you can cast that cantrip, and it counts as an artificer cantrip for you. Once this property is used, it can't be used again until the next dawn.
At a first reading, my interpretation is that you can choose a cantrip once per day, and you can then cast that cantrip as often as you want (for the next eight hours).
However, I'm realizing it doesn't actually say how many times you can cast the cantrip during that time. This could also potentially be read as letting you cast the cantrip once during those eight hours, and then not being able to cast it again until "this property" recharges.
How can I be sure which interpretation is correct?