diff --git a/svc-deploy b/svc-deploy
index 8962985d8..01bd2cda7 100755
--- a/svc-deploy
+++ b/svc-deploy
@@ -1,10 +1,21 @@
 #!/bin/bash
 
+# deploy a service to a cluster
+# ./svc-deploy <deploy-env> <dir> <cluster>
+# this script expects the <dir> to contain a Makefile.tmpl.mk template that can
+# be processed with ./templatized according to config/config.yml
+
 cd $(dirname "$(realpath "${BASH_SOURCE[0]}")")
 
 export DEPLOY_ENV=$1
 export DIR=$2
 export CLUSTER=$3
+
+if [[ "$CLUSTER" != "svc" && "$CLUSTER" != "mgmt" ]]; then
+    echo "Error: CLUSTER must be either 'svc' or 'mgmt'."
+    exit 1
+fi
+
 export KUBECONFIG=$(./dev-infrastructure/make $DEPLOY_ENV $CLUSTER.aks.kubeconfigfile)
 
 ./templatize $DEPLOY_ENV $DIR/Makefile.tmpl.mk $DIR/Makefile