Alarm IsCondition Expression

in below example i am traying to use TagName as param in tag name . as shown in below screenshot
example 1 is working fine.
But in example (2) when trying to replace 0 to TagName which name is (0) it's not working.

You cannot nest curly braces. Use another (custom) property with an indirect tag binding to obtain the desired tag, then use that custom property with your jsonGet() expression.