diff --git a/backend/agent/tools/sb_files_tool.py b/backend/agent/tools/sb_files_tool.py
index 590df309..7e192c8a 100644
--- a/backend/agent/tools/sb_files_tool.py
+++ b/backend/agent/tools/sb_files_tool.py
@@ -540,12 +540,12 @@ def authenticate_user(username, password):
             await self.sandbox.fs.upload_file(new_content.encode(), full_path)
             
             # Return rich data for frontend diff view
-            return self.success_response({
+            return ToolResult(success=True, output=json.dumps({
                 "message": f"File '{target_file}' edited successfully.",
                 "file_path": target_file,
                 "original_content": original_content,
                 "updated_content": new_content
-            })
+            }))
                     
         except Exception as e:
             logger.error(f"Unhandled error in edit_file: {str(e)}", exc_info=True)
diff --git a/frontend/src/components/thread/tool-views/file-operation/_utils.ts b/frontend/src/components/thread/tool-views/file-operation/_utils.ts
index af6ebf31..a762a347 100644
--- a/frontend/src/components/thread/tool-views/file-operation/_utils.ts
+++ b/frontend/src/components/thread/tool-views/file-operation/_utils.ts
@@ -289,7 +289,7 @@ export const extractFileEditData = (
             filePath: parsed.file_path || null,
             originalContent: parsed.original_content ?? null,
             updatedContent: parsed.updated_content ?? null,
-            success: true, // Assume success if we have content
+            success: parsed.updated_content !== null, // Success is false if updated_content is null
             timestamp: null,
             errorMessage: parsed.message,
         };