diff --git a/object/service.proto b/object/service.proto
index 1d08ff5..4ff36a3 100644
--- a/object/service.proto
+++ b/object/service.proto
@@ -106,7 +106,9 @@ service ObjectService {
   // - **CONTAINER_NOT_FOUND** (3072, SECTION_CONTAINER): \
   //   object container not found;
   // - **TOKEN_EXPIRED** (4097, SECTION_SESSION): \
-  //   provided session token has expired.
+  //   provided session token has expired;
+  // - **OBJECT_ALREADY_REMOVED** (2052, SECTION_OBJECT): \
+  //   object has been already marked as removed.
   rpc Delete(DeleteRequest) returns (DeleteResponse);
 
   // Returns the object Headers without data payload. By default full header is