From dce01d84c5257ebc6a2490b4517f2b0cb2531d54 Mon Sep 17 00:00:00 2001
From: mateo <mateo@berri.ai>
Date: Fri, 16 Oct 2026 21:39:13 +0000
Subject: [PATCH] fix(responses): drop metadata from compact requests to OpenAI
 and Azure

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
---
 .../llms/openai/responses/transformation.py   | 10 ++++-
 .../test_openai_responses_transformation.py   | 37 +++++++++++++++++++
 2 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/litellm/llms/openai/responses/transformation.py b/litellm/llms/openai/responses/transformation.py
index 768d89b9a97..e7800115e68 100644
--- a/litellm/llms/openai/responses/transformation.py
+++ b/litellm/llms/openai/responses/transformation.py
@@ -63,6 +63,7 @@ _PROVIDERS_VALIDATING_TOOL_CALL_ITEM_IDS: Final = frozenset({LlmProviders.AZURE,
 _PROVIDERS_REPLAYING_ONLY_THEIR_OWN_REASONING: Final = _PROVIDERS_VALIDATING_TOOL_CALL_ITEM_IDS
 _ROLES_READING_PROMPT_CACHE_BREAKPOINTS: Final = frozenset({"system", "developer", "user"})
 _PART_TYPES_READING_PROMPT_CACHE_BREAKPOINTS: Final = frozenset({"input_text", "input_image", "input_file"})
+_COMPACT_UNSUPPORTED_PARAMS: Final = frozenset({"metadata"})
 _INPUT_ITEM: Final[TypeAdapter[Mapping[str, object]]] = TypeAdapter(Mapping[str, object])
 _CONTENT_PARTS: Final[TypeAdapter[Sequence[Mapping[str, object]]]] = TypeAdapter(Sequence[Mapping[str, object]])
 
@@ -1163,7 +1164,14 @@ class OpenAIResponsesAPIConfig(BaseResponsesAPIConfig):
         if sanitized_tools is not None:
             response_api_optional_request_params["tools"] = sanitized_tools
         data: Final = dict(
-            ResponsesAPIRequestParams(model=model, input=replay_safe_input, **response_api_optional_request_params)
+            ResponsesAPIRequestParams(
+                model=model,
+                input=replay_safe_input,
+                **cast(  # cast-ok: the inherited base signature leaves caller parameters untyped
+                    "ResponsesAPIOptionalRequestParams",
+                    {key: value for key, value in request_params.items() if key not in _COMPACT_UNSUPPORTED_PARAMS},
+                ),
+            )
         )
 
         return url, data
diff --git a/tests/unit/llms/openai/responses/test_openai_responses_transformation.py b/tests/unit/llms/openai/responses/test_openai_responses_transformation.py
index 0da28e7207e..342ca19ac69 100644
--- a/tests/unit/llms/openai/responses/test_openai_responses_transformation.py
+++ b/tests/unit/llms/openai/responses/test_openai_responses_transformation.py
@@ -1630,6 +1630,43 @@ class TestTransformListInputItemsRequest:
         assert data["model"] == "gpt-4o"
         assert data["input"] == "hello"
 
+    @pytest.mark.parametrize(
+        ("config", "api_base"),
+        [
+            pytest.param(
+                OpenAIResponsesAPIConfig(),
+                "https://api.openai.com/v1/responses",
+                id="openai",
+            ),
+            pytest.param(
+                AzureOpenAIResponsesAPIConfig(),
+                "https://x.openai.azure.com/openai/v1/responses?api-version=preview",
+                id="azure",
+            ),
+        ],
+    )
+    def test_compact_response_request_omits_metadata(
+        self,
+        config: OpenAIResponsesAPIConfig | AzureOpenAIResponsesAPIConfig,
+        api_base: str,
+    ) -> None:
+        _, data = config.transform_compact_response_api_request(
+            model="gpt-5-mini",
+            input="hi",
+            response_api_optional_request_params={
+                "metadata": {"a": "b"},
+                "instructions": "be brief",
+                "previous_response_id": "resp_1",
+            },
+            api_base=api_base,
+            litellm_params=GenericLiteLLMParams(),
+            headers={},
+        )
+
+        assert "metadata" not in data
+        assert data["instructions"] == "be brief"
+        assert data["previous_response_id"] == "resp_1"
+
     def test_azure_transform_list_input_items_request_minimal(self):
         """Test Azure implementation with minimal parameters"""
         # Setup