diff --git a/python/packages/server/src/officeconvert_server/models.py b/python/packages/server/src/officeconvert_server/models.py
index bd6dc4c..e73b487 100644
--- a/python/packages/server/src/officeconvert_server/models.py
+++ b/python/packages/server/src/officeconvert_server/models.py
@@ -6,6 +6,7 @@ from dataclasses import dataclass, field
 from datetime import datetime, timezone
 from pathlib import Path
 from typing import Any
+from officeconvertapi.v1 import conversion_pb2
 
 def utc_now() -> datetime:
     """Return the current UTC timestamp with timezone information."""
@@ -20,7 +21,7 @@ class ConversionSession:
     source_filename: str
     bucket_name: str
     upload_object_key: str
-    status: int
+    status: conversion_pb2.ConversionStatus
     created_at: datetime = field(default_factory=utc_now)
     updated_at: datetime = field(default_factory=utc_now)
     error_message: str = ""
diff --git a/python/packages/server/src/officeconvert_server/storage.py b/python/packages/server/src/officeconvert_server/storage.py
index 1bdd215..49c5740 100644
--- a/python/packages/server/src/officeconvert_server/storage.py
+++ b/python/packages/server/src/officeconvert_server/storage.py
@@ -71,13 +71,24 @@ class S3Store:
         """Remove all objects in a bucket and then delete the bucket."""
         objects = list(self._client.list_objects(bucket_name, recursive=True))
         if objects:
+            delete_requests: list[DeleteObject] = []
+            for obj in objects:
+                object_name = obj.object_name
+                if object_name is None:
+                    raise RuntimeError(
+                        "encountered unnamed object while removing bucket contents"
+                    )
+                delete_requests.append(DeleteObject(object_name))
+
             errors = self._client.remove_objects(
                 bucket_name,
-                [DeleteObject(obj.object_name) for obj in objects],
+                delete_requests,
             )
             for err in errors:
+                object_name = err.name or "<unknown>"
+                message = err.message or err.code
                 raise RuntimeError(
-                    f"failed to delete object {err.object_name}: {err.message}"
+                    f"failed to delete object {object_name}: {message}"
                 )
         try:
             self._client.remove_bucket(bucket_name)