From 1656e7ea642769286a200b3e5395b87c66c54a04 Mon Sep 17 00:00:00 2001
From: PriyanJindal <pjindal@arize.com>
Date: Tue, 1 Sep 2026 15:22:35 -0700
Subject: [PATCH] fix(responses): propagate chat bridge stream errors

---
 .../transformation.py                         | 38 +++++++++++
 ...responses_transformation_transformation.py | 67 +++++++++++++++++++
 2 files changed, 105 insertions(+)

diff --git a/litellm/completion_extras/litellm_responses_transformation/transformation.py b/litellm/completion_extras/litellm_responses_transformation/transformation.py
index 7368de1e968..0ac2849f1ef 100644
--- a/litellm/completion_extras/litellm_responses_transformation/transformation.py
+++ b/litellm/completion_extras/litellm_responses_transformation/transformation.py
@@ -1368,6 +1368,21 @@ class OpenAiResponsesToChatCompletionStreamIterator(BaseModelResponseIterator):
                     )
                 ]
             )
+        elif event_type in (ResponsesAPIStreamEvents.RESPONSE_FAILED, ResponsesAPIStreamEvents.ERROR):
+            from litellm.responses.streaming_iterator import _error_event_fields, _status_code_for_error_fields
+
+            error_payload: Final = (
+                parsed_chunk.get("response", {}).get("error")
+                if event_type == ResponsesAPIStreamEvents.RESPONSE_FAILED
+                else parsed_chunk.get("error")
+            )
+            error_message, error_type, error_code = _error_event_fields(error_payload)
+            raise litellm.APIError(
+                status_code=_status_code_for_error_fields(error_type, error_code),
+                message=error_message,
+                llm_provider="openai",
+                model="responses",
+            )
         elif event_type == "response.output_item.added":
             # New output item added
             output_item = parsed_chunk.get("item", {})
@@ -1498,6 +1513,29 @@ class OpenAiResponsesToChatCompletionStreamIterator(BaseModelResponseIterator):
                 )
             else:
                 raise ValueError(f"Chat provider: Invalid text delta {parsed_chunk}")
+        elif event_type == ResponsesAPIStreamEvents.REFUSAL_DELTA:
+            refusal: Final = parsed_chunk.get("delta")
+            if isinstance(refusal, str):
+                return ModelResponseStream(
+                    choices=[
+                        StreamingChoices(
+                            index=0,
+                            delta=Delta(refusal=refusal),
+                            finish_reason=None,
+                        )
+                    ]
+                )
+            raise ValueError(f"Chat provider: Invalid refusal delta {parsed_chunk}")
+        elif event_type == ResponsesAPIStreamEvents.REFUSAL_DONE:
+            return ModelResponseStream(
+                choices=[
+                    StreamingChoices(
+                        index=0,
+                        delta=Delta(),
+                        finish_reason=None,
+                    )
+                ]
+            )
         elif event_type == "response.reasoning_summary_text.delta":
             content_part = parsed_chunk.get("delta", None)
             if content_part:
diff --git a/tests/test_litellm/completion_extras/litellm_responses_transformation/test_completion_extras_litellm_responses_transformation_transformation.py b/tests/test_litellm/completion_extras/litellm_responses_transformation/test_completion_extras_litellm_responses_transformation_transformation.py
index 21b60d7a216..2115517aa0b 100644
--- a/tests/test_litellm/completion_extras/litellm_responses_transformation/test_completion_extras_litellm_responses_transformation_transformation.py
+++ b/tests/test_litellm/completion_extras/litellm_responses_transformation/test_completion_extras_litellm_responses_transformation_transformation.py
@@ -3796,6 +3796,73 @@ def test_response_incomplete_stream_event_without_details_defaults_to_length():
     assert result.choices[0].finish_reason == "length"
 
 
+@pytest.mark.parametrize(
+    ("event", "expected_status"),
+    [
+        (
+            {
+                "type": "response.failed",
+                "response": {
+                    "error": {
+                        "type": "server_error",
+                        "code": "server_error",
+                        "message": "generation failed",
+                    }
+                },
+            },
+            500,
+        ),
+        (
+            {
+                "type": "error",
+                "error": {
+                    "type": "invalid_request_error",
+                    "code": "invalid_prompt",
+                    "message": "prompt was rejected",
+                },
+            },
+            400,
+        ),
+    ],
+)
+def test_response_stream_errors_raise_litellm_api_errors(event, expected_status):
+    from litellm.completion_extras.litellm_responses_transformation.transformation import (
+        OpenAiResponsesToChatCompletionStreamIterator,
+    )
+
+    iterator = OpenAiResponsesToChatCompletionStreamIterator(
+        streaming_response=iter([f"data: {json.dumps(event)}"]), sync_stream=True
+    )
+
+    with pytest.raises(litellm.APIError) as exc_info:
+        next(iterator)
+
+    assert exc_info.value.status_code == expected_status
+    assert event.get("error", event.get("response", {}).get("error"))["message"] in str(exc_info.value)
+
+
+def test_response_refusal_stream_events_preserve_refusal_delta_without_duplication():
+    from litellm.completion_extras.litellm_responses_transformation.transformation import (
+        OpenAiResponsesToChatCompletionStreamIterator,
+    )
+
+    iterator = OpenAiResponsesToChatCompletionStreamIterator(
+        streaming_response=iter(
+            [
+                'data: {"type":"response.refusal.delta","delta":"I cannot help with that."}',
+                'data: {"type":"response.refusal.done","refusal":"I cannot help with that."}',
+            ]
+        ),
+        sync_stream=True,
+    )
+
+    delta = next(iterator)
+    done = next(iterator)
+
+    assert delta.choices[0].delta.get("refusal") == "I cannot help with that."
+    assert done.choices[0].delta.get("refusal") is None
+
+
 def test_assistant_message_with_tool_calls_keeps_its_content():
     """Regression for https://github.com/BerriAI/litellm/issues/24985.