diff --git a/format/seat-definition.schema.json b/format/seat-definition.schema.json
index 7ca51ea..dfba914 100644
--- a/format/seat-definition.schema.json
+++ b/format/seat-definition.schema.json
@@ -359,6 +359,10 @@
         "needs-approval": {
           "type": "boolean",
           "description": "the verb runs only on the operator's Approve of the call, for every holder (design 46 milestone 7, 2)"
+        },
+        "by-caller": {
+          "type": "boolean",
+          "description": "the holder's process answers the verb itself and tells callers apart by the account the bus proved (ADR 0259 3; design 47 G 554, 621, 656)"
         }
       }
     },