diff --git a/scripts/setup.sh b/scripts/setup.sh
index a7ebc8369..979215d5d 100755
--- a/scripts/setup.sh
+++ b/scripts/setup.sh
@@ -6,6 +6,7 @@
 
 set -xeu
 
+# Fail earlier if required variables are not set
 test -n ${PYDOC_VERSION+x}
 test -n ${PYDOC_REPO+x}
 test -n ${PYDOC_LANGUAGE+x}