Prometheus metrics at gateway: UNKNOWN instead of a path in uri

Question

I'm using prometheus metrics in my project. In the gateway, I see UNKNOWN in the metrics

http_server_requests_seconds_count{exception="None",method="PUT",outcome="SUCCESS",status="200",uri="UNKNOWN",} 8.0

Spring sets this value in WebMvcTags in the uri method because it doesn't find a pattern. How to make a path instead of UNKNOWN? Should I set a pattern?