diff --git a/openapi/openapiv2.json b/openapi/openapiv2.json
index 61d98c55a..2e047a214 100644
--- a/openapi/openapiv2.json
+++ b/openapi/openapiv2.json
@@ -16985,6 +16985,11 @@
         "identity": {
           "type": "string",
           "description": "The identity of the client who started this operation."
+        },
+        "stateSizeBytes": {
+          "type": "string",
+          "format": "int64",
+          "description": "Updated once on scheduled and once on terminal status."
         }
       },
       "description": "Full current state of a standalone Nexus operation, as of the time of the request."
@@ -17038,6 +17043,11 @@
         "executionDuration": {
           "type": "string",
           "description": "The difference between close time and scheduled time.\nThis field is only populated if the operation is closed."
+        },
+        "stateSizeBytes": {
+          "type": "string",
+          "format": "int64",
+          "description": "Updated once on scheduled and once on terminal status."
         }
       },
       "description": "Limited Nexus operation information returned in the list response.\nWhen adding fields here, ensure that it is also present in NexusOperationExecutionInfo (note that it may already be present in\nNexusOperationExecutionInfo but not at the top-level)."
diff --git a/openapi/openapiv3.yaml b/openapi/openapiv3.yaml
index f7053f93a..bc79eb4fc 100644
--- a/openapi/openapiv3.yaml
+++ b/openapi/openapiv3.yaml
@@ -13371,6 +13371,9 @@ components:
         identity:
           type: string
           description: The identity of the client who started this operation.
+        stateSizeBytes:
+          type: string
+          description: Updated once on scheduled and once on terminal status.
       description: Full current state of a standalone Nexus operation, as of the time of the request.
     NexusOperationExecutionListInfo:
       type: object
@@ -13423,6 +13426,9 @@ components:
           description: |-
             The difference between close time and scheduled time.
              This field is only populated if the operation is closed.
+        stateSizeBytes:
+          type: string
+          description: Updated once on scheduled and once on terminal status.
       description: |-
         Limited Nexus operation information returned in the list response.
          When adding fields here, ensure that it is also present in NexusOperationExecutionInfo (note that it may already be present in
diff --git a/temporal/api/nexus/v1/message.proto b/temporal/api/nexus/v1/message.proto
index ec03a2ac7..a4e400c29 100644
--- a/temporal/api/nexus/v1/message.proto
+++ b/temporal/api/nexus/v1/message.proto
@@ -329,6 +329,9 @@ message NexusOperationExecutionInfo {
 
     // The identity of the client who started this operation.
     string identity = 28;
+
+    // Updated once on scheduled and once on terminal status.
+    int64 state_size_bytes = 29;
 }
 
 // Limited Nexus operation information returned in the list response.
@@ -362,4 +365,7 @@ message NexusOperationExecutionListInfo {
     // The difference between close time and scheduled time.
     // This field is only populated if the operation is closed.
     google.protobuf.Duration execution_duration = 11;
+
+    // Updated once on scheduled and once on terminal status.
+    int64 state_size_bytes = 12;
 }