The very useful undertow_request_count_total metric is missing a tag for which resource and path it is reported for.  

 
For example it would be very useful if the metrics would look like below or something in the line with that?  
 

      undertow_request_count_total {path="/rest/v2/cool/smurfs" , resource="SmurfResource.java" } 

 
 
Also there is some questions if you have an endpoint with where you have a variable as the path:  

@Path("/rest/v2/cool/smurf/{smurfId}") 

That can possible report a very big set of tags thus I suggest reporting this in the metric:

     undertow_request_count_total {path="/rest/v2/cool/smurf/{smurfId}" , resource="SmurfResource.java" }