diff --git a/schema/metadata/aclDefs.json b/schema/metadata/aclDefs.json
index 38f286a526..6de9251542 100644
--- a/schema/metadata/aclDefs.json
+++ b/schema/metadata/aclDefs.json
@@ -30,7 +30,7 @@
             "type": "string"
         },
         "linkCheckerClassNameMap": {
-            "description": "Link checker classes for specific links.",
+            "description": "Link checker classes for specific links. Should implement `Espo\\Core\\Acl\\LinkChecker`.",
             "type": "object",
             "additionalProperties": {
                 "type": "string"