diff --git a/cc/config/tidy.go b/cc/config/tidy.go
index ba1043b..fb9ac49 100644
--- a/cc/config/tidy.go
+++ b/cc/config/tidy.go
@@ -122,6 +122,7 @@
 	{"hardware/qcom", tidyExternalVendor},
 	{"vendor/", tidyExternalVendor},
 	{"vendor/google", tidyDefault},
+	{"vendor/google_arc/libs/org.chromium.arc.mojom", tidyExternalVendor},
 	{"vendor/google_devices", tidyExternalVendor},
 }