From 756d4df1cde9f36d4e66a3945f83bec5c1d97ff1 Mon Sep 17 00:00:00 2001
From: mateo-berri <277851410+mateo-berri@users.noreply.github.com>
Date: Mon, 9 Nov 2026 19:17:51 -0800
Subject: [PATCH] fix(proxy): keep the top-level model on the Responses
 fallback metadata event

---
 litellm/proxy/proxy_server.py                           | 6 +++++-
 tests/unit/proxy/proxy_server/test_streaming_helpers.py | 2 ++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/litellm/proxy/proxy_server.py b/litellm/proxy/proxy_server.py
index 22204a12f4b..76af150b4e3 100644
--- a/litellm/proxy/proxy_server.py
+++ b/litellm/proxy/proxy_server.py
@@ -9918,7 +9918,11 @@ def _format_fallback_metadata_sse_event(
 ) -> str | bytes:
     litellm_fallback: Final = {"fallback_model": fallback_model, "errors": fallback_errors}
     if error_state is not None:
-        event: Final = {"type": _RESPONSES_FALLBACK_METADATA_EVENT_TYPE, "litellm_fallback": litellm_fallback}
+        event: Final = {
+            "type": _RESPONSES_FALLBACK_METADATA_EVENT_TYPE,
+            "model": fallback_model or "",
+            "litellm_fallback": litellm_fallback,
+        }
         error_state.observe_chunk(event)
         return error_state.mark_emitted(f"data: {json.dumps(event)}\n\n")
     payload: Final = {
diff --git a/tests/unit/proxy/proxy_server/test_streaming_helpers.py b/tests/unit/proxy/proxy_server/test_streaming_helpers.py
index 689f9aba45e..58e5b362f4b 100644
--- a/tests/unit/proxy/proxy_server/test_streaming_helpers.py
+++ b/tests/unit/proxy/proxy_server/test_streaming_helpers.py
@@ -952,8 +952,10 @@ async def test_responses_stream_sends_fallback_metadata_as_a_typed_event_framed_
     )
     assert payloads[1] == {
         "type": "litellm.fallback_metadata",
+        "model": "fallback-model",
         "litellm_fallback": {"fallback_model": "fallback-model", "errors": fallback_errors},
     }
+    assert {payload.get("model") for payload in payloads} == {"fallback-model"}
     assert len({frame.startswith("event: ") for frame in event_frames}) == 1