diff --git a/utils/attic-token.bash b/utils/attic-token.bash
index ff7f8fd..4b2febf 100755
--- a/utils/attic-token.bash
+++ b/utils/attic-token.bash
@@ -1,8 +1,13 @@
 #!/usr/bin/env bash
 
-cache=""
-cache_pattern=""
-token_type=""
+if (( $# != 3 )); then
+   echo "usage: $0 <cache/cache group> <cache pattern> <token type>"
+   exit 1
+fi
+
+cache="$1"
+cache_pattern="$2"
+token_type="$3"
 
 case $token_type in
     "cache-creator")