diff -r 8a0c727aa409 -r 17ccf828a2f2 dav/sync.c
--- a/dav/sync.c	Tue May 29 20:15:09 2018 +0200
+++ b/dav/sync.c	Tue May 29 20:38:22 2018 +0200
@@ -2297,6 +2297,11 @@
             tags = parse_csv_taglist(tags_str, strlen(tags_str));
             store_tags = TRUE;
             // TODO: read from stdin if tags_str is "-"
+        } else if (args->argc == 1) {
+            store_tags = TRUE;
+        } else {
+            fprintf(stderr, "Too many arguments\n");
+            ret = -1;
         }
     }