From 561e0f4d1d453368cffdfc75f0939d08ec46e52a Mon Sep 17 00:00:00 2001
From: Mrunmayee Daware <165297479+Mrun25@users.noreply.github.com>
Date: Fri, 30 Oct 2026 18:57:31 +0530
Subject: [PATCH] fix(responses): return deduplicated input without list
 parameter mutation

---
 litellm/responses/utils.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/litellm/responses/utils.py b/litellm/responses/utils.py
index a697b24cbf6..ce0bcc80c56 100644
--- a/litellm/responses/utils.py
+++ b/litellm/responses/utils.py
@@ -597,8 +597,7 @@ class ResponsesAPIRequestUtils:
                     seen_ids.add(item_id)
             restored_input.append(item)
 
-        request_input[:] = restored_input
-        return request_input
+        return cast(_RequestInputT, restored_input)  # cast-ok: list inputs retain their input type after deduplication
 
     _restore_encrypted_content_item_ids_in_input = restore_encrypted_content_item_ids_in_input