diff --git a/opentelemetry/src/main/java/io/grpc/opentelemetry/OpenTelemetryMetricsModule.java b/opentelemetry/src/main/java/io/grpc/opentelemetry/OpenTelemetryMetricsModule.java
index 82ad41e7b20..f7990f60fa4 100644
--- a/opentelemetry/src/main/java/io/grpc/opentelemetry/OpenTelemetryMetricsModule.java
+++ b/opentelemetry/src/main/java/io/grpc/opentelemetry/OpenTelemetryMetricsModule.java
@@ -466,6 +466,7 @@ private static final class ServerTracer extends ServerStreamTracer {
       this.fullMethodName = fullMethodName;
       this.streamPlugins = checkNotNull(streamPlugins, "streamPlugins");
       this.stopwatch = module.stopwatchSupplier.get().start();
+      isGeneratedMethod = fullMethodName != null;
     }
 
     @Override