From b6dea9c5fc0cc08dac12835a48e8b0f31991db21 Mon Sep 17 00:00:00 2001
From: Denis Shulyaka <Shulyaka@gmail.com>
Date: Mon, 7 Sep 2026 09:32:22 +0300
Subject: [PATCH] Fix OpenAI prompt caching (#181472)

---
 homeassistant/components/openai_conversation/entity.py    | 1 +
 tests/components/openai_conversation/test_ai_task.py      | 4 ++++
 tests/components/openai_conversation/test_conversation.py | 5 +++--
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/homeassistant/components/openai_conversation/entity.py b/homeassistant/components/openai_conversation/entity.py
index aa0d05ae98e9..8402b3d12058 100644
--- a/homeassistant/components/openai_conversation/entity.py
+++ b/homeassistant/components/openai_conversation/entity.py
@@ -517,6 +517,7 @@ class OpenAIBaseLLMEntity(Entity):
             input=messages,
             max_output_tokens=options.get(CONF_MAX_TOKENS, RECOMMENDED_MAX_TOKENS),
             user=chat_log.conversation_id,
+            prompt_cache_key=self.subentry.subentry_id,
             service_tier=options.get(CONF_SERVICE_TIER, RECOMMENDED_SERVICE_TIER),
             store=options.get(CONF_STORE_RESPONSES, RECOMMENDED_STORE_RESPONSES),
             stream=True,
diff --git a/tests/components/openai_conversation/test_ai_task.py b/tests/components/openai_conversation/test_ai_task.py
index dc2d70265766..b123dc497d4a 100644
--- a/tests/components/openai_conversation/test_ai_task.py
+++ b/tests/components/openai_conversation/test_ai_task.py
@@ -66,6 +66,10 @@ async def test_generate_data(
     assert result.data == "The test data"
     assert mock_create_stream.call_args is not None
     assert mock_create_stream.call_args.kwargs["store"] is expected_store
+    assert (
+        mock_create_stream.call_args.kwargs["prompt_cache_key"]
+        == ai_task_entry.subentry_id
+    )
 
 
 @pytest.mark.usefixtures("mock_init_component")
diff --git a/tests/components/openai_conversation/test_conversation.py b/tests/components/openai_conversation/test_conversation.py
index 933e57bc7d1b..199ccbb23b00 100644
--- a/tests/components/openai_conversation/test_conversation.py
+++ b/tests/components/openai_conversation/test_conversation.py
@@ -823,13 +823,13 @@ async def test_flex_tier_retry(
 @pytest.mark.parametrize(
     "subentry_options", [{CONF_CHAT_MODEL: "gpt-5.6-sol", CONF_PRO_MODE: True}]
 )
+@pytest.mark.usefixtures("mock_init_component")
 async def test_model_args(
     hass: HomeAssistant,
     mock_config_entry: MockConfigEntry,
-    mock_init_component,
     mock_create_stream: AsyncMock,
     snapshot: SnapshotAssertion,
-    subentry_options: dict,
+    subentry_options: dict[str, str | bool],
 ) -> None:
     """Test model arguments for various configuration."""
 
@@ -860,4 +860,5 @@ async def test_model_args(
     model_args = mock_create_stream.call_args.kwargs.copy()
     model_args.pop("input")
     assert model_args.pop("user") == result.conversation_id
+    assert model_args.pop("prompt_cache_key") == subentry.subentry_id
     assert model_args == snapshot