diff --git a/bin/tests/system/digdelv/tests.sh b/bin/tests/system/digdelv/tests.sh
index d4db46f1c6..ae986e4a51 100644
--- a/bin/tests/system/digdelv/tests.sh
+++ b/bin/tests/system/digdelv/tests.sh
@@ -707,7 +707,7 @@ if [ -x "$DIG" ]; then
     dig_with_opts @10.53.0.3 +yaml +ednsopt=key-tag:00010002 a.example +qr >dig.out.test$n 2>&1 || ret=1
     $PYTHON yamlget.py dig.out.test$n 0 message query_message_data OPT_PSEUDOSECTION EDNS KEY-TAG >yamlget.out.test$n 2>&1 || ret=1
     read -r value <yamlget.out.test$n
-    [ "$value" = "1, 2" ] || ret=1
+    [ "$value" = "[1, 2]" ] || ret=1
     if [ $ret -ne 0 ]; then echo_i "failed"; fi
     status=$((status + ret))
   fi
diff --git a/lib/dns/message.c b/lib/dns/message.c
index 3effcb4211..9657b0776a 100644
--- a/lib/dns/message.c
+++ b/lib/dns/message.c
@@ -3783,7 +3783,7 @@ dns_message_pseudosectiontoyaml(dns_message_t *msg, dns_pseudosection_t section,
 				break;
 			case DNS_OPT_KEY_TAG:
 				if (optlen > 0U && (optlen % 2U) == 0U) {
-					const char *sep = "";
+					const char *sep = " [";
 					while (optlen > 0U) {
 						uint16_t id =
 							isc_buffer_getuint16(
@@ -3794,7 +3794,7 @@ dns_message_pseudosectiontoyaml(dns_message_t *msg, dns_pseudosection_t section,
 						sep = ",";
 						optlen -= 2;
 					}
-					ADD_STRING(target, "\n");
+					ADD_STRING(target, " ]\n");
 					continue;
 				}
 				break;