diff --git a/agent_based_epidemic_sim/core/BUILD b/agent_based_epidemic_sim/core/BUILD
index 488e685..12fc89f 100644
--- a/agent_based_epidemic_sim/core/BUILD
+++ b/agent_based_epidemic_sim/core/BUILD
@@ -329,6 +329,11 @@ cc_test(
     srcs = [
         "location_discrete_event_simulator_test.cc",
     ],
+    # copybara:comment_begin
+    tags = [
+        "optonly",
+    ],
+    # copybara:comment_end
     deps = [
         ":broker",
         ":event",