Hello,
In his case since it looks like this
[
{
"[KPI_Value]": 0.9215686274509803
}
]
I would do it like this
split(trim(split(string(outputs('Compose')),':')[1]),'}')[0]
Where it first turns it into a string, so it can be split by the :, and then again split by the }

And it only shows the input as the same as the output because the input is based on the code I have so thats expect.
Cheers
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Thank You
Michael Gernaey MCT | MCSE | Ex-Microsoft
https://gernaeysoftware.com
LinkedIn: https://www.linkedin.com/in/michaelgernaey