Add a GetHomeState tool to return the current state of the home (#140971)

* Add a GetHomeState tool to return the current state of the home

* Fix check for exposing entities

* Add "all" to get home state description

tests/helpers/test_llm.py

@@ -181,19 +181,19 @@ async def test_assist_api(
 
     assert len(llm.async_get_apis(hass)) == 1
     api = await llm.async_get_api(hass, "assist", llm_context)
-    assert len(api.tools) == 0
+    assert [tool.name for tool in api.tools] == ["get_home_state"]
 
     # Match all
     intent_handler.platforms = None
 
     api = await llm.async_get_api(hass, "assist", llm_context)
-    assert len(api.tools) == 1
+    assert [tool.name for tool in api.tools] == ["test_intent", "get_home_state"]
 
     # Match specific domain
     intent_handler.platforms = {"light"}
 
     api = await llm.async_get_api(hass, "assist", llm_context)
-    assert len(api.tools) == 1
+    assert len(api.tools) == 2
     tool = api.tools[0]
     assert tool.name == "test_intent"
     assert tool.description == "Execute Home Assistant test_intent intent"
@@ -643,6 +643,15 @@ async def test_assist_api_prompt(
 {exposed_entities_prompt}"""
     )
 
+    # Verify that the get_home_state tool returns the same results as the exposed_entities_prompt
+    result = await api.async_call_tool(
+        llm.ToolInput(tool_name="get_home_state", tool_args={})
+    )
+    assert result == {
+        "success": True,
+        "result": exposed_entities_prompt,
+    }
+
     # Fake that request is made from a specific device ID with an area
     llm_context.device_id = device.id
     area_prompt = (
@@ -1267,3 +1276,19 @@ async def test_calendar_get_events_tool(hass: HomeAssistant) -> None:
         "start_date_time": now,
         "end_date_time": dt_util.start_of_local_day() + timedelta(days=7),
     }
+
+
+async def test_no_tools_exposed(hass: HomeAssistant) -> None:
+    """Test that tools are not exposed when no entities are exposed."""
+    assert await async_setup_component(hass, "homeassistant", {})
+    context = Context()
+    llm_context = llm.LLMContext(
+        platform="test_platform",
+        context=context,
+        user_prompt="test_text",
+        language="*",
+        assistant="conversation",
+        device_id=None,
+    )
+    api = await llm.async_get_api(hass, "assist", llm_context)
+    assert api.tools == []