diff --git a/scripts/celerity/generate_sprites.php b/scripts/celerity/generate_sprites.php
index 83ca46d766..d967666fd9 100755
--- a/scripts/celerity/generate_sprites.php
+++ b/scripts/celerity/generate_sprites.php
@@ -55,9 +55,11 @@ function gly($y) {
 }
 
 $sheet = new PhutilSpriteSheet();
+$at = '@';
 $sheet->setCSSHeader(<<<EOCSS
 /**
  * @provides autosprite-css
+ * {$at}generated
  */
 
 .autosprite {
diff --git a/webroot/rsrc/css/autosprite.css b/webroot/rsrc/css/autosprite.css
index ee0c33254b..3a88bba802 100644
--- a/webroot/rsrc/css/autosprite.css
+++ b/webroot/rsrc/css/autosprite.css
@@ -1,5 +1,6 @@
 /**
  * @provides autosprite-css
+ * @generated
  */
 
 .autosprite {