JSL Regex matching square brackets [ ]

[#1]

\[ doesnt seem to go well within quotes.. Is there a solution here?

[#2]

You need to do some extra escaping for the opening

str = "i am {name} [age]";
reg = Regex(str, "\!\[\w+\]");

https://www.jmp.com/support/help/en/18.1/jmp/jsl-syntax-rules.shtml

Edit: Some explanation here How do you replace square brackets "[" "]" in a string with Regex? (JMP strings make a special case of \[ and ]\ anywhere in a JMP string to turn off JMP's escaping.)