diff --git a/homeassistant/components/openai_conversation/entity.py b/homeassistant/components/openai_conversation/entity.py
index 69ca4c9a1eb..7351cbccbfa 100644
--- a/homeassistant/components/openai_conversation/entity.py
+++ b/homeassistant/components/openai_conversation/entity.py
@@ -293,6 +293,7 @@ class OpenAIBaseLLMEntity(Entity):
                 "top_p": options.get(CONF_TOP_P, RECOMMENDED_TOP_P),
                 "temperature": options.get(CONF_TEMPERATURE, RECOMMENDED_TEMPERATURE),
                 "user": chat_log.conversation_id,
+                "store": False,
                 "stream": True,
             }
             if tools:
@@ -304,8 +305,7 @@ class OpenAIBaseLLMEntity(Entity):
                         CONF_REASONING_EFFORT, RECOMMENDED_REASONING_EFFORT
                     )
                 }
-            else:
-                model_args["store"] = False
+                model_args["include"] = ["reasoning.encrypted_content"]
 
             try:
                 result = await client.responses.create(**model_args)
diff --git a/tests/components/openai_conversation/conftest.py b/tests/components/openai_conversation/conftest.py
index b8944d837be..628c1846e16 100644
--- a/tests/components/openai_conversation/conftest.py
+++ b/tests/components/openai_conversation/conftest.py
@@ -5,7 +5,10 @@ from unittest.mock import patch
 
 import pytest
 
-from homeassistant.components.openai_conversation.const import DEFAULT_CONVERSATION_NAME
+from homeassistant.components.openai_conversation.const import (
+    CONF_CHAT_MODEL,
+    DEFAULT_CONVERSATION_NAME,
+)
 from homeassistant.config_entries import ConfigSubentryData
 from homeassistant.const import CONF_LLM_HASS_API
 from homeassistant.core import HomeAssistant
@@ -59,6 +62,19 @@ def mock_config_entry_with_assist(
     return mock_config_entry
 
 
+@pytest.fixture
+def mock_config_entry_with_reasoning_model(
+    hass: HomeAssistant, mock_config_entry: MockConfigEntry
+) -> MockConfigEntry:
+    """Mock a config entry with assist."""
+    hass.config_entries.async_update_subentry(
+        mock_config_entry,
+        next(iter(mock_config_entry.subentries.values())),
+        data={CONF_LLM_HASS_API: llm.LLM_API_ASSIST, CONF_CHAT_MODEL: "o4-mini"},
+    )
+    return mock_config_entry
+
+
 @pytest.fixture
 async def mock_init_component(
     hass: HomeAssistant, mock_config_entry: MockConfigEntry
diff --git a/tests/components/openai_conversation/test_conversation.py b/tests/components/openai_conversation/test_conversation.py
index 3d662cb0f00..7a3bcb21768 100644
--- a/tests/components/openai_conversation/test_conversation.py
+++ b/tests/components/openai_conversation/test_conversation.py
@@ -499,6 +499,7 @@ def create_reasoning_item(id: str, output_index: int) -> list[ResponseStreamEven
                 summary=[],
                 type="reasoning",
                 status=None,
+                encrypted_content="AAA",
             ),
             output_index=output_index,
             sequence_number=0,
@@ -510,6 +511,7 @@ def create_reasoning_item(id: str, output_index: int) -> list[ResponseStreamEven
                 summary=[],
                 type="reasoning",
                 status=None,
+                encrypted_content="AAABBB",
             ),
             output_index=output_index,
             sequence_number=0,
@@ -566,7 +568,7 @@ def create_web_search_item(id: str, output_index: int) -> list[ResponseStreamEve
 
 async def test_function_call(
     hass: HomeAssistant,
-    mock_config_entry_with_assist: MockConfigEntry,
+    mock_config_entry_with_reasoning_model: MockConfigEntry,
     mock_init_component,
     mock_create_stream: AsyncMock,
     mock_chat_log: MockChatLog,  # noqa: F811
@@ -617,7 +619,7 @@ async def test_function_call(
         "id": "rs_A",
         "summary": [],
         "type": "reasoning",
-        "encrypted_content": None,
+        "encrypted_content": "AAABBB",
     }
     assert result.response.response_type == intent.IntentResponseType.ACTION_DONE
     # Don't test the prompt, as it's not deterministic