diff --git a/homeassistant/components/openai_conversation/conversation.py b/homeassistant/components/openai_conversation/conversation.py
index 67e79e270d7..126a4713fb5 100644
--- a/homeassistant/components/openai_conversation/conversation.py
+++ b/homeassistant/components/openai_conversation/conversation.py
@@ -141,6 +141,11 @@ async def _transform_stream(
             if isinstance(event.item, ResponseOutputMessage):
                 yield {"role": event.item.role}
             elif isinstance(event.item, ResponseFunctionToolCall):
+                # OpenAI has tool calls as individual events
+                # while HA puts tool calls inside the assistant message.
+                # We turn them into individual assistant content for HA
+                # to ensure that tools are called as soon as possible.
+                yield {"role": "assistant"}
                 current_tool_call = event.item
         elif isinstance(event, ResponseOutputItemDoneEvent):
             item = event.item.model_dump()
diff --git a/tests/components/openai_conversation/snapshots/test_conversation.ambr b/tests/components/openai_conversation/snapshots/test_conversation.ambr
index 77c28de2773..0f874969aff 100644
--- a/tests/components/openai_conversation/snapshots/test_conversation.ambr
+++ b/tests/components/openai_conversation/snapshots/test_conversation.ambr
@@ -17,13 +17,6 @@
           }),
           'tool_name': 'test_tool',
         }),
-        dict({
-          'id': 'call_call_2',
-          'tool_args': dict({
-            'param1': 'call2',
-          }),
-          'tool_name': 'test_tool',
-        }),
       ]),
     }),
     dict({
@@ -33,6 +26,20 @@
       'tool_name': 'test_tool',
       'tool_result': 'value1',
     }),
+    dict({
+      'agent_id': 'conversation.openai',
+      'content': None,
+      'role': 'assistant',
+      'tool_calls': list([
+        dict({
+          'id': 'call_call_2',
+          'tool_args': dict({
+            'param1': 'call2',
+          }),
+          'tool_name': 'test_tool',
+        }),
+      ]),
+    }),
     dict({
       'agent_id': 'conversation.openai',
       'role': 'tool_result',
@@ -48,3 +55,38 @@
     }),
   ])
 # ---
+# name: test_function_call_without_reasoning
+  list([
+    dict({
+      'content': 'Please call the test function',
+      'role': 'user',
+    }),
+    dict({
+      'agent_id': 'conversation.openai',
+      'content': None,
+      'role': 'assistant',
+      'tool_calls': list([
+        dict({
+          'id': 'call_call_1',
+          'tool_args': dict({
+            'param1': 'call1',
+          }),
+          'tool_name': 'test_tool',
+        }),
+      ]),
+    }),
+    dict({
+      'agent_id': 'conversation.openai',
+      'role': 'tool_result',
+      'tool_call_id': 'call_call_1',
+      'tool_name': 'test_tool',
+      'tool_result': 'value1',
+    }),
+    dict({
+      'agent_id': 'conversation.openai',
+      'content': 'Cool',
+      'role': 'assistant',
+      'tool_calls': None,
+    }),
+  ])
+# ---
diff --git a/tests/components/openai_conversation/test_conversation.py b/tests/components/openai_conversation/test_conversation.py
index 269590b483a..99559cb3b61 100644
--- a/tests/components/openai_conversation/test_conversation.py
+++ b/tests/components/openai_conversation/test_conversation.py
@@ -596,6 +596,48 @@ async def test_function_call(
     assert mock_chat_log.content[1:] == snapshot
 
 
+async def test_function_call_without_reasoning(
+    hass: HomeAssistant,
+    mock_config_entry_with_assist: MockConfigEntry,
+    mock_init_component,
+    mock_create_stream: AsyncMock,
+    mock_chat_log: MockChatLog,  # noqa: F811
+    snapshot: SnapshotAssertion,
+) -> None:
+    """Test function call from the assistant."""
+    mock_create_stream.return_value = [
+        # Initial conversation
+        (
+            *create_function_tool_call_item(
+                id="fc_1",
+                arguments=['{"para', 'm1":"call1"}'],
+                call_id="call_call_1",
+                name="test_tool",
+                output_index=1,
+            ),
+        ),
+        # Response after tool responses
+        create_message_item(id="msg_A", text="Cool", output_index=0),
+    ]
+    mock_chat_log.mock_tool_results(
+        {
+            "call_call_1": "value1",
+        }
+    )
+
+    result = await conversation.async_converse(
+        hass,
+        "Please call the test function",
+        mock_chat_log.conversation_id,
+        Context(),
+        agent_id="conversation.openai",
+    )
+
+    assert result.response.response_type == intent.IntentResponseType.ACTION_DONE
+    # Don't test the prompt, as it's not deterministic
+    assert mock_chat_log.content[1:] == snapshot
+
+
 @pytest.mark.parametrize(
     ("description", "messages"),
     [