From ab2d6e4eac89ee562cd3c608641a0b182bb733e1 Mon Sep 17 00:00:00 2001
From: Jay Prajapati <79649559+jayy-77@users.noreply.github.com>
Date: Sat, 14 Feb 2026 23:48:49 +0530
Subject: [PATCH 1/2] fix(chatgpt): drop unsupported responses params for Codex

Co-authored-by: Cursor <cursoragent@cursor.com>
---
 .../llms/chatgpt/responses/transformation.py  | 21 ++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/litellm/llms/chatgpt/responses/transformation.py b/litellm/llms/chatgpt/responses/transformation.py
index 0ce24f63a89..bcb6edd39f9 100644
--- a/litellm/llms/chatgpt/responses/transformation.py
+++ b/litellm/llms/chatgpt/responses/transformation.py
@@ -73,10 +73,6 @@ class ChatGPTResponsesAPIConfig(OpenAIResponsesAPIConfig):
             litellm_params,
             headers,
         )
-        request.pop("max_output_tokens", None)
-        request.pop("max_tokens", None)
-        request.pop("max_completion_tokens", None)
-        request.pop("metadata", None)
         base_instructions = get_chatgpt_default_instructions()
         existing_instructions = request.get("instructions")
         if existing_instructions:
@@ -92,7 +88,22 @@ class ChatGPTResponsesAPIConfig(OpenAIResponsesAPIConfig):
         if "reasoning.encrypted_content" not in include:
             include.append("reasoning.encrypted_content")
         request["include"] = include
-        return request
+
+        allowed_keys = {
+            "model",
+            "input",
+            "instructions",
+            "stream",
+            "store",
+            "include",
+            "tools",
+            "tool_choice",
+            "reasoning",
+            "previous_response_id",
+            "truncation",
+        }
+
+        return {k: v for k, v in request.items() if k in allowed_keys}
 
     def transform_response_api_response(
         self,

From 35bbcf9e9889ecf0e41d81f6543f506ee9c055a7 Mon Sep 17 00:00:00 2001
From: Jay Prajapati <79649559+jayy-77@users.noreply.github.com>
Date: Sat, 14 Feb 2026 23:48:53 +0530
Subject: [PATCH 2/2] test(chatgpt): ensure Codex request filters unsupported
 params

Co-authored-by: Cursor <cursoragent@cursor.com>
---
 .../test_chatgpt_responses_transformation.py  | 39 +++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/tests/test_litellm/llms/chatgpt/responses/test_chatgpt_responses_transformation.py b/tests/test_litellm/llms/chatgpt/responses/test_chatgpt_responses_transformation.py
index bec748d8dc8..03cea8785bc 100644
--- a/tests/test_litellm/llms/chatgpt/responses/test_chatgpt_responses_transformation.py
+++ b/tests/test_litellm/llms/chatgpt/responses/test_chatgpt_responses_transformation.py
@@ -88,6 +88,45 @@ class TestChatGPTResponsesAPITransformation:
             "You are Codex, based on GPT-5."
         )
 
+    def test_chatgpt_drops_unsupported_responses_params(self):
+        config = ChatGPTResponsesAPIConfig()
+        request = config.transform_responses_api_request(
+            model="chatgpt/gpt-5.2-codex",
+            input="hi",
+            response_api_optional_request_params={
+                # unsupported by ChatGPT Codex
+                "user": "user_123",
+                "temperature": 0.2,
+                "top_p": 0.9,
+                "context_management": [{"type": "compaction", "compact_threshold": 200000}],
+                "metadata": {"foo": "bar"},
+                "max_output_tokens": 123,
+                "stream_options": {"include_usage": True},
+                # supported and should be preserved
+                "truncation": "auto",
+                "previous_response_id": "resp_123",
+                "reasoning": {"effort": "medium"},
+                "tools": [{"type": "function", "function": {"name": "hello"}}],
+                "tool_choice": {"type": "function", "function": {"name": "hello"}},
+            },
+            litellm_params=GenericLiteLLMParams(),
+            headers={},
+        )
+
+        assert "user" not in request
+        assert "temperature" not in request
+        assert "top_p" not in request
+        assert "context_management" not in request
+        assert "metadata" not in request
+        assert "max_output_tokens" not in request
+        assert "stream_options" not in request
+
+        assert request["truncation"] == "auto"
+        assert request["previous_response_id"] == "resp_123"
+        assert request["reasoning"] == {"effort": "medium"}
+        assert request["tools"] == [{"type": "function", "function": {"name": "hello"}}]
+        assert request["tool_choice"] == {"type": "function", "function": {"name": "hello"}}
+
     def test_chatgpt_non_stream_sse_response_parsing(self):
         config = ChatGPTResponsesAPIConfig()
         response_payload = {