diff --git a/src/core/lib/channel/channel_stack_builder.cc b/src/core/lib/channel/channel_stack_builder.cc
index 05bbae71d37..72985b807fe 100644
--- a/src/core/lib/channel/channel_stack_builder.cc
+++ b/src/core/lib/channel/channel_stack_builder.cc
@@ -71,7 +71,7 @@ void grpc_channel_stack_builder_set_target(grpc_channel_stack_builder* b,
 
 std::string grpc_channel_stack_builder_get_target(
     grpc_channel_stack_builder* b) {
-  return b->target == nullptr ? std::string() : std::string(b->target);
+  return b->target == nullptr ? std::string("unknown") : std::string(b->target);
 }
 
 static grpc_channel_stack_builder_iterator* create_iterator_at_filter_node(