diff --git a/domain_tests/in_grammar_domain_test.cc b/domain_tests/in_grammar_domain_test.cc
index 196ab3e..a3dcce3 100644
--- a/domain_tests/in_grammar_domain_test.cc
+++ b/domain_tests/in_grammar_domain_test.cc
@@ -29,6 +29,7 @@
 namespace fuzztest {
 namespace {
 
+// TODO(changochen): Add documentation.
 TEST(InJsonGrammar, InitGeneratesDifferentValidJson) {
   absl::BitGen bitgen;
   auto domain = InJsonGrammar();