diff --git a/apm-network/src/main/proto/DiscoveryService.proto b/apm-network/src/main/proto/DiscoveryService.proto
index c1a14bcfb..cda0fa286 100644
--- a/apm-network/src/main/proto/DiscoveryService.proto
+++ b/apm-network/src/main/proto/DiscoveryService.proto
@@ -20,7 +20,8 @@ service InstanceDiscoveryService {
 
 message ApplicationInstance {
     int32 applicationId = 1;
-    int64 registerTime = 2;
+    string agentUUID = 2;
+    int64 registerTime = 3;
 }
 
 message ApplicationInstanceMapping {
@@ -61,4 +62,4 @@ message ServiceNameMappingElement {
 message ServiceNameElement {
     string serviceName = 1;
     int32 applicationId = 2;
-}
\ No newline at end of file
+}