diff --git a/protobuf/flow/executiondata/executiondata.proto b/protobuf/flow/executiondata/executiondata.proto
index 67b2fef79..69d541155 100644
--- a/protobuf/flow/executiondata/executiondata.proto
+++ b/protobuf/flow/executiondata/executiondata.proto
@@ -466,7 +466,7 @@ message SubscribeEventsResponse {
   // Timestamp from the block containing the events.
   google.protobuf.Timestamp block_timestamp = 4;
 
-  // The message index of the response message. Used by the client to ensure they received all messages. Starts from "1".
+  // The message index of the response message. Used by the client to ensure they received all messages. Starts from "0".
   uint64 message_index = 5;
 }
 
@@ -618,7 +618,7 @@ message SubscribeAccountStatusesResponse {
   // Block height of the block containing the events.
   uint64 block_height = 2;
 
-  // The message index of the response message. Used by the client to ensure they received all messages. Starts from "1".
+  // The message index of the response message. Used by the client to ensure they received all messages. Starts from "0".
   uint64 message_index = 3;
 
   message Result {