fix: omit chat completions store by default

Author: Aphroq

src/agents/models/chatcmpl_helpers.py

@@ -29,9 +29,7 @@ def is_openai(cls, client: AsyncOpenAI) -> bool:
 
     @classmethod
     def get_store_param(cls, client: AsyncOpenAI, model_settings: ModelSettings) -> bool | None:
-        # Match the behavior of Responses where store is True when not given
-        default_store = True if cls.is_openai(client) else None
-        return model_settings.store if model_settings.store is not None else default_store
+        return model_settings.store
 
     @classmethod
     def get_stream_options_param(

tests/models/test_openai_chatcompletions.py

@@ -577,12 +577,12 @@ def __init__(self, completions: DummyCompletions) -> None:
 
 
 def test_store_param():
-    """Should default to True for OpenAI API calls, and False otherwise."""
+    """Should omit store unless it is explicitly set."""
 
     model_settings = ModelSettings()
     client = AsyncOpenAI()
-    assert ChatCmplHelpers.get_store_param(client, model_settings) is True, (
-        "Should default to True for OpenAI API calls"
+    assert ChatCmplHelpers.get_store_param(client, model_settings) is None, (
+        "Should omit store when not specified for Chat Completions"
     )
 
     model_settings = ModelSettings(store=False)