diff --git a/daemon/mqtt.c b/daemon/mqtt.c
index 7053f86a2..22e4619c4 100644
--- a/daemon/mqtt.c
+++ b/daemon/mqtt.c
@@ -161,8 +161,10 @@ static void mqtt_call_stats(call_t *call, JsonBuilder *json) {
 
 
 static void mqtt_monologue_stats(struct call_monologue *ml, JsonBuilder *json) {
-	json_builder_set_member_name(json, "tag");
-	glib_json_builder_add_str(json, &ml->tag);
+	if (ml->tag.len) {
+		json_builder_set_member_name(json, "tag");
+		glib_json_builder_add_str(json, &ml->tag);
+	}
 
 	if (ml->label.len) {
 		json_builder_set_member_name(json, "label");