diff --git a/include/scrimmage/simcontrol/SimControl.h b/include/scrimmage/simcontrol/SimControl.h
index 0d7f0b121d..40549c08b2 100644
--- a/include/scrimmage/simcontrol/SimControl.h
+++ b/include/scrimmage/simcontrol/SimControl.h
@@ -212,7 +212,8 @@ class SimControl {
      * parameters.
      */
     bool generate_entity(const int &ent_desc_id,
-                         std::map<std::string, std::string> &params);
+                         std::map<std::string, std::string> &params,
+                         int request_id=0);
 
     /// @brief Get the pointer to the MissionParser instance.
     MissionParsePtr mp();
diff --git a/msgs/Event.proto b/msgs/Event.proto
index 00b6dcbf13..2b24cea1bf 100644
--- a/msgs/Event.proto
+++ b/msgs/Event.proto
@@ -26,6 +26,7 @@ message UserForcedExit {
 
 message EntityGenerated {
         int32 entity_id = 1;
+        int32 request_id = 2;
 }
 
 message EntityRemoved {
@@ -45,4 +46,5 @@ message GenerateEntity {
         scrimmage_proto.State state = 2;
         repeated KeyValuePair entity_param = 3;
         int32 entity_id = 4;
+        int32 request_id = 5;
 }
diff --git a/src/simcontrol/SimControl.cpp b/src/simcontrol/SimControl.cpp
index c8385e5cdc..bb8ca3fac3 100644
--- a/src/simcontrol/SimControl.cpp
+++ b/src/simcontrol/SimControl.cpp
@@ -282,11 +282,12 @@ bool SimControl::generate_entity(const int &ent_desc_id) {
     if (it_params == mp_->entity_descriptions().end()) {
         return false;
     }
-    return generate_entity(ent_desc_id, it_params->second);
+    return generate_entity(ent_desc_id, it_params->second, 0);
 }
 
 bool SimControl::generate_entity(const int &ent_desc_id,
-                                 std::map<std::string, std::string> &params) {
+                                 std::map<std::string, std::string> &params,
+                                 int request_id) {
 #if ENABLE_JSBSIM == 1
     params["JSBSIM_ROOT"] = jsbsim_root_;
 #endif
@@ -394,6 +395,7 @@ bool SimControl::generate_entity(const int &ent_desc_id,
 
     auto msg = std::make_shared<Message<sm::EntityGenerated>>();
     msg->data.set_entity_id(ent->id().id());
+    msg->data.set_request_id(request_id);
     pub_ent_gen_->publish(msg);
 
     return true;
@@ -864,10 +866,13 @@ bool SimControl::start() {
             params[msg->data.entity_param(i).key()] = msg->data.entity_param(i).value();
         }
 
+        int request_id = 0;
+        request_id = msg->data.request_id();
+
         // Recreate the rtree with one additional size for this entity.
         this->create_rtree(1);
 
-        if (not this->generate_entity(it_ent_desc_id->second, params)) {
+        if (not this->generate_entity(it_ent_desc_id->second, params, request_id)) {
             cout << "Failed to generate entity with tag: "
                  << msg->data.entity_tag() << endl;
             return;