diff --git a/src/check b/src/check
index 9f95f56..481e77d 100755
--- a/src/check
+++ b/src/check
@@ -4,9 +4,4 @@ set -eu
 
 [ -e /opt/resource/common ] && cd /opt/resource
 . ./common
-
-jq -r tostring << EOF
-[
-    $(crane digest "$REPOSITORY:$TAG")
-]
-EOF
+jq --null-input --arg version "$(crane digest "$REPOSITORY:$TAG")" '[$version]'
diff --git a/src/in b/src/in
index a70e2ad..5cc3e43 100755
--- a/src/in
+++ b/src/in
@@ -11,4 +11,4 @@ cd "$oci_dir"
 tar cf "$1/image.tar" ./*
 cd - 1>&2
 
-echo "$(jq -r .version < "$INPUT_FILE")"
+echo "$(jq .version < "$INPUT_FILE")"
diff --git a/src/out b/src/out
index 916c74b..59c2607 100755
--- a/src/out
+++ b/src/out
@@ -11,4 +11,4 @@ cd "$oci_dir"
 tar xf "$1/$(jq -r .params.image < "$INPUT_FILE")"
 cd - 1>&2
 crane push "$oci_dir" "$REPOSITORY:$TAG" --image-refs="$IMAGE_REFS_FILE"
-sed 's/^[^@]*@//' < "$IMAGE_REFS_FILE"
+jq --null-input --arg version "$(sed 's/^[^@]*@//' < "$IMAGE_REFS_FILE")" '$version'