diff --git a/src/kaleidoscope_internal/sketch_preprocessing/sketch_header.h b/src/kaleidoscope_internal/sketch_preprocessing/sketch_header.h
index 34fea268..17a4780f 100644
--- a/src/kaleidoscope_internal/sketch_preprocessing/sketch_header.h
+++ b/src/kaleidoscope_internal/sketch_preprocessing/sketch_header.h
@@ -1 +1,3 @@
 // Any code that appears here is added to the top of the preprocessed sketch file.
+
+#define KALEIDOSCOPE_SKETCH