From d569e2b91ff5160bc857afb1e9ebef4feac505b9 Mon Sep 17 00:00:00 2001
From: MarkXian <mark-xian@foxmail.com>
Date: Sat, 29 Aug 2026 11:13:59 +0800
Subject: [PATCH] fix(router): justify fallback stream cast

---
 litellm/router.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/litellm/router.py b/litellm/router.py
index 8b1487222cc..a2e12f85388 100644
--- a/litellm/router.py
+++ b/litellm/router.py
@@ -5207,7 +5207,9 @@ class Router:
             wrapper.adopt_fallback_source(fallback_response)
             if hasattr(fallback_response, "__aiter__"):
                 fallback_stream: Final = await self._aanthropic_messages_streaming_iterator(
-                    response=cast("AsyncIterator[bytes]", fallback_response),
+                    response=cast(  # cast-ok: __aiter__ check established the streaming fallback shape
+                        "AsyncIterator[bytes]", fallback_response
+                    ),
                     initial_kwargs=initial_kwargs,
                     allow_fallback=False,
                 )