diff --git a/packages/pigeon/CHANGELOG.md b/packages/pigeon/CHANGELOG.md
index 32c08225e63..fd7d766a21e 100644
--- a/packages/pigeon/CHANGELOG.md
+++ b/packages/pigeon/CHANGELOG.md
@@ -1,6 +1,7 @@
 ## 13.1.2
 
 * Adds compatibilty with `analyzer` 6.x.
+* [cpp] Fix C++ generator skipping FlutterError if no FlutterAPI is defined.
 
 ## 13.1.1
 
diff --git a/packages/pigeon/lib/cpp_generator.dart b/packages/pigeon/lib/cpp_generator.dart
index fb52a13aa83..35ee2a0e137 100644
--- a/packages/pigeon/lib/cpp_generator.dart
+++ b/packages/pigeon/lib/cpp_generator.dart
@@ -196,9 +196,14 @@ class CppHeaderGenerator extends StructuredGenerator<CppOptions> {
     final bool hasFlutterApi = root.apis.any((Api api) =>
         api.methods.isNotEmpty && api.location == ApiLocation.flutter);
 
-    if (hasHostApi) {
+    // Always write?
+    if (hasFlutterApi || hasHostApi) {
       _writeErrorOr(indent, friends: root.apis.map((Api api) => api.name));
     }
+
+    if (hasHostApi) {
+      // Nothing yet
+    }
     if (hasFlutterApi) {
       // Nothing yet.
     }