diff --git a/templates/bazelisk.yml b/templates/bazelisk.yml
index aee690476c31c6536d954fa44e19fabb5dc02940..3aa4886648fbc52fa948ceb726f948dc62a9526e 100644
--- a/templates/bazelisk.yml
+++ b/templates/bazelisk.yml
@@ -33,6 +33,10 @@ spec:
       VARIABLES="${VARIABLES-$[[inputs.variables]]}"
       while IFS= read -r LINE; do
         for VARIABLE in ${VARIABLES}; do
+            if test -z ${!VARIABLE+x}; then
+                printf >&2 '\e[1;33mWarning:\e[0m `\e[1;35m%s\e[0m` is not available in the environment for run commands replacement\n' "${VARIABLE}"
+                continue
+            fi
             LINE="${LINE//\$\{${VARIABLE}\}/${!VARIABLE}}"
         done
         printf '%s\n' "${LINE}" >> "${ROOT}/$[[inputs.dst]]"