From 016e7cb9769e82d720e76fb25dbee3f9f4f188e7 Mon Sep 17 00:00:00 2001
From: ccurme <chester.curme@gmail.com>
Date: Fri, 7 Aug 2026 09:14:09 -0400
Subject: [PATCH] fix(openai): handle `ContextWindowExceededError` (#39300)

---
 .../langchain_openai/chat_models/base.py      |  1 +
 .../tests/unit_tests/chat_models/test_base.py | 25 +++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/libs/partners/openai/langchain_openai/chat_models/base.py b/libs/partners/openai/langchain_openai/chat_models/base.py
index 576b24f7eb..e39433fb47 100644
--- a/libs/partners/openai/langchain_openai/chat_models/base.py
+++ b/libs/partners/openai/langchain_openai/chat_models/base.py
@@ -564,6 +564,7 @@ def _handle_openai_bad_request(e: openai.BadRequestError) -> None:
         "context_length_exceeded" in str(e)
         or "Input tokens exceed the configured limit" in e.message
         or "prompt is too long" in e.message
+        or "ContextWindowExceededError" in e.message
     ):
         raise OpenAIContextOverflowError(
             message=e.message, response=e.response, body=e.body
diff --git a/libs/partners/openai/tests/unit_tests/chat_models/test_base.py b/libs/partners/openai/tests/unit_tests/chat_models/test_base.py
index e4c953f6d2..5c54c458e6 100644
--- a/libs/partners/openai/tests/unit_tests/chat_models/test_base.py
+++ b/libs/partners/openai/tests/unit_tests/chat_models/test_base.py
@@ -4507,6 +4507,31 @@ def test_context_overflow_error_prompt_too_long() -> None:
     assert "prompt is too long" in str(exc_info.value)
 
 
+def test_context_overflow_error_context_window_exceeded() -> None:
+    """Test context overflow error triggered by ContextWindowExceededError."""
+    error_body = {
+        "error": {
+            "message": "ContextWindowExceededError: maximum context length exceeded",
+            "type": "invalid_request_error",
+            "param": "messages",
+            "code": "invalid_request_error",
+        }
+    }
+    bad_request_error = openai.BadRequestError(
+        message=error_body["error"]["message"],
+        response=MagicMock(status_code=400),
+        body=error_body,
+    )
+    llm = ChatOpenAI()
+
+    with patch.object(llm.client, "with_raw_response") as mock_client:
+        mock_client.create.side_effect = bad_request_error
+        with pytest.raises(ContextOverflowError) as exc_info:
+            llm.invoke([HumanMessage(content="test")])
+
+    assert "ContextWindowExceededError" in str(exc_info.value)
+
+
 def test_context_overflow_error_backwards_compatibility() -> None:
     """Test that ContextOverflowError can be caught as BadRequestError."""
     llm = ChatOpenAI()