Calling Functions using REST APIs

i want to know where i can see the graph of restapi base function and also see the log , to check why that function failed.

i can see in the audit log that my function failed but don't know the reason why its failed.

if a custom function failed in automation i can see why that failed by going in the 

settings > automation > actions > custom function and then click on the tab

but where i can the same thing like this for rest api function ?