Paeon, you are doing it right. Your variable mySnippet is persistent as is. I’m trying to think of why it’s not working for you and can think of only 2 reasons, either 1) you are resetting the variable somewhere else in your script or 2) you are editing the script in script editor and pressing the “compile” button. Every time you press compile in script editor the persistent variable is forgotten and reset to the initial value.
Run this several times and you will see it works fine…
property mySnippet : ""
display dialog "Before choose: " & mySnippet
set mySnippet to (choose file) as text
display dialog "After choose: " & mySnippet
So you see nothing is wrong with the persistent variable.