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

homeassistant/helpers/llm.py

@@ -66,6 +66,11 @@ Answer questions about the world truthfully.
 Answer in plain text. Keep it simple and to the point.
 """
 
+NO_ENTITIES_PROMPT = (
+    "Only if the user wants to control a device, tell them to expose entities "
+    "to their voice assistant in Home Assistant."
+)
+
 
 @callback
 def async_render_no_api_prompt(hass: HomeAssistant) -> str:
@@ -329,10 +334,7 @@ class AssistAPI(API):
         self, llm_context: LLMContext, exposed_entities: dict | None
     ) -> str:
         if not exposed_entities or not exposed_entities["entities"]:
-            return (
-                "Only if the user wants to control a device, tell them to expose entities "
-                "to their voice assistant in Home Assistant."
-            )
+            return NO_ENTITIES_PROMPT
         return "\n".join(
             [
                 *self._async_get_preable(llm_context),
@@ -454,6 +456,9 @@ class AssistAPI(API):
                 for script_entity_id in exposed_entities[SCRIPT_DOMAIN]
             )
 
+        if exposed_domains:
+            tools.append(GetHomeStateTool())
+
         return tools
 
 
@@ -885,3 +890,39 @@ class CalendarGetEventsTool(Tool):
         ]
 
         return {"success": True, "result": events}
+
+
+class GetHomeStateTool(Tool):
+    """Tool for getting the current state of exposed entities.
+
+    This returns state for all entities that have been exposed to
+    the assistant. This is different than the GetState intent, which
+    returns state for entities based on intent parameters.
+    """
+
+    name = "get_home_state"
+    description = "Get the current state of all devices in the home. "
+
+    async def async_call(
+        self,
+        hass: HomeAssistant,
+        tool_input: ToolInput,
+        llm_context: LLMContext,
+    ) -> JsonObjectType:
+        """Get the current state of exposed entities."""
+        if llm_context.assistant is None:
+            # Note this doesn't happen in practice since this tool won't be
+            # exposed if no assistant is configured.
+            return {"success": False, "error": "No assistant configured"}
+
+        exposed_entities = _get_exposed_entities(hass, llm_context.assistant)
+        if not exposed_entities["entities"]:
+            return {"success": False, "error": NO_ENTITIES_PROMPT}
+        prompt = [
+            "An overview of the areas and the devices in this smart home:",
+            yaml_util.dump(list(exposed_entities["entities"].values())),
+        ]
+        return {
+            "success": True,
+            "result": "\n".join(prompt),
+        }

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 == []