diff --git a/api/message/types.go b/api/message/types.go
index d8948e3..b012b79 100644
--- a/api/message/types.go
+++ b/api/message/types.go
@@ -64,8 +64,10 @@ type ActionTrace struct {
 	// Contract account.
 	Contract string `json:"contract" msgpack:"contract"`
 
-	Receiver string      `json:"receiver" msgpack:"receiver"`
-	Data     interface{} `json:"data" msgpack:"data"`
+	Receiver      string `json:"receiver" msgpack:"receiver"`
+	FirstReceiver bool   `json:"first_receiver" msgpack:"first_receiver"`
+
+	Data interface{} `json:"data" msgpack:"data"`
 
 	Authorization []PermissionLevel `json:"authorization" msgpack:"authorization"`