diff --git a/.clang-tidy b/.clang-tidy
index 9a2afcc5..b1b6561e 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -23,6 +23,7 @@ performance-*,
 -performance-noexcept-move-constructor,
 -performance-unnecessary-value-param,
 readability-const-return-type,
+readability-container-contains,
 readability-redundant-declaration,
 readability-redundant-string-init,
 clang-analyzer-core.*,
diff --git a/test/mp/test/test.cpp b/test/mp/test/test.cpp
index 7f465a33..5ecb7cc4 100644
--- a/test/mp/test/test.cpp
+++ b/test/mp/test/test.cpp
@@ -181,7 +181,7 @@ KJ_TEST("Call FooInterface methods")
     }
     KJ_EXPECT(in.unordered_set_int.size() == out.unordered_set_int.size());
     for (const auto& elem : in.unordered_set_int) {
-        KJ_EXPECT(out.unordered_set_int.count(elem) == 1);
+        KJ_EXPECT(out.unordered_set_int.contains(elem));
     }
     KJ_EXPECT(in.vector_bool.size() == out.vector_bool.size());
     for (size_t i = 0; i < in.vector_bool.size(); ++i) {