diff --git a/app_dart/lib/src/request_handlers/github/webhook_subscription.dart b/app_dart/lib/src/request_handlers/github/webhook_subscription.dart
index 0e59cd9..96a7b68 100644
--- a/app_dart/lib/src/request_handlers/github/webhook_subscription.dart
+++ b/app_dart/lib/src/request_handlers/github/webhook_subscription.dart
@@ -416,7 +416,7 @@
           filename.endsWith('.m') ||
           filename.endsWith('.java') ||
           filename.endsWith('.cc')) {
-        needsTests = true;
+        needsTests = !_allChangesAreCodeComments(file);
       }
 
       if (kEngineTestRegExp.hasMatch(filename)) {
diff --git a/app_dart/test/request_handlers/github/webhook_subscription_test.dart b/app_dart/test/request_handlers/github/webhook_subscription_test.dart
index 9740d49..09e00ed 100644
--- a/app_dart/test/request_handlers/github/webhook_subscription_test.dart
+++ b/app_dart/test/request_handlers/github/webhook_subscription_test.dart
@@ -1610,6 +1610,46 @@
       ));
     });
 
+    test('Engine does not comment for comment-only changes', () async {
+      const int issueNumber = 123;
+
+      tester.message = generateGithubWebhookMessage(
+        action: 'opened',
+        number: issueNumber,
+        slug: Config.engineSlug,
+      );
+      const String patch = '''
+@@ -128,7 +128,7 @@
+
+/// Insert interesting comment here.
+///
+-/// More details here, but some of them are wrong.
++/// These are the right details!
+void foo() {
+  int bar = 0;
+  String baz = '';
+''';
+
+      when(pullRequestsService.listFiles(Config.engineSlug, issueNumber)).thenAnswer(
+        (_) => Stream<PullRequestFile>.fromIterable(<PullRequestFile>[
+          PullRequestFile()
+            ..filename = 'flutter/lib/ui/foo.dart'
+            ..additionsCount = 1
+            ..deletionsCount = 1
+            ..changesCount = 2
+            ..patch = patch,
+        ]),
+      );
+
+      await tester.post(webhook);
+
+      verifyNever(issuesService.createComment(
+        Config.engineSlug,
+        issueNumber,
+        argThat(contains(config.missingTestsPullRequestMessageValue)),
+      ));
+    });
+
     test('No labels when only pubspec.yaml changes', () async {
       const int issueNumber = 123;