fix(openai): omit timeout from client_params when not set by user

libs/partners/openai/langchain_openai/chat_models/base.py

@@ -1022,10 +1022,11 @@ def validate_environment(self) -> Self:
         client_params: dict = {
             "organization": self.openai_organization,
             "base_url": self.openai_api_base,
-            "timeout": self.request_timeout,
             "default_headers": self.default_headers,
             "default_query": self.default_query,
         }
+        if self.request_timeout is not None:
+            client_params["timeout"] = self.request_timeout
         if self.max_retries is not None:
             client_params["max_retries"] = self.max_retries
 

libs/partners/openai/tests/unit_tests/chat_models/test_base.py

@@ -127,6 +127,20 @@ def test_openai_client_caching() -> None:
     assert llm1.root_client._client is not llm7.root_client._client
 
 
+def test_timeout_omitted_from_client_params_when_none() -> None:
+    """Timeout should be omitted from client_params when None (default),
+    letting the SDK's built-in default apply."""
+    with patch("openai.OpenAI") as mock_sync:
+        ChatOpenAI(model="gpt-4.1-mini", api_key=SecretStr("test"))
+        sync_kwargs = mock_sync.call_args
+        assert "timeout" not in sync_kwargs.kwargs
+
+    with patch("openai.OpenAI") as mock_sync:
+        ChatOpenAI(model="gpt-4.1-mini", api_key=SecretStr("test"), timeout=30)
+        sync_kwargs = mock_sync.call_args
+        assert sync_kwargs.kwargs.get("timeout") == 30
+
+
 def test_profile() -> None:
     model = ChatOpenAI(model="gpt-4")
     assert model.profile