diff --git a/homeassistant/components/cloud/entity.py b/homeassistant/components/cloud/entity.py
index 2c7fcf2fe244..ab24892a9056 100644
--- a/homeassistant/components/cloud/entity.py
+++ b/homeassistant/components/cloud/entity.py
@@ -84,7 +84,7 @@ def _convert_content_to_param(
                 and content.tool_call_id in web_search_calls
             ):
                 web_search_call = web_search_calls.pop(content.tool_call_id)
-                web_search_call["status"] = content.tool_result.get(
+                web_search_call["status"] = content.result.data.get(
                     "status", "completed"
                 )
                 messages.append(cast("ResponseInputItemParam", web_search_call))
@@ -93,7 +93,12 @@ def _convert_content_to_param(
                     {
                         "type": "function_call_output",
                         "call_id": content.tool_call_id,
-                        "output": json_dumps(content.tool_result),
+                        "output": json_dumps(
+                            {
+                                "data": content.result.data,
+                                "error": content.result.error,
+                            }
+                        ),
                     }
                 )
             continue
@@ -316,7 +321,10 @@ async def _transform_stream(  # noqa: C901 - This is complex, but better to have
                     "role": "tool_result",
                     "tool_call_id": event.item.id,
                     "tool_name": "web_search_call",
-                    "tool_result": {"status": event.item.status},
+                    "result": llm.ToolResult(
+                        data={"status": event.item.status},
+                        error=event.item.status == "failed",
+                    ),
                 }
                 last_role = "tool_result"
             elif isinstance(event.item, LLMResponseImageOutputItem):
diff --git a/tests/components/cloud/test_entity.py b/tests/components/cloud/test_entity.py
index 7c522f8483d1..c9b9362ade86 100644
--- a/tests/components/cloud/test_entity.py
+++ b/tests/components/cloud/test_entity.py
@@ -327,3 +327,40 @@ async def test_async_handle_chat_log_service_sets_structured_output_non_strict(
     _, kwargs = cloud.llm.async_generate_data.call_args
 
     assert kwargs["response_format"]["json_schema"]["strict"] is False
+
+
+@pytest.mark.parametrize(
+    ("result", "expected_output"),
+    [
+        pytest.param(
+            llm.ToolResult(data={"temperature": 21}),
+            '{"data":{"temperature":21},"error":false}',
+            id="success",
+        ),
+        pytest.param(
+            llm.ToolResult(data={"error": "Not found"}, error=True),
+            '{"data":{"error":"Not found"},"error":true}',
+            id="error",
+        ),
+    ],
+)
+def test_convert_tool_result_to_param(
+    result: llm.ToolResult, expected_output: str
+) -> None:
+    """Test the tool result is sent with its error flag."""
+    content = [
+        conversation.ToolResultContent(
+            agent_id="agent",
+            tool_call_id="mock-tool-call-id",
+            tool_name="HassGetState",
+            result=result,
+        )
+    ]
+
+    assert _convert_content_to_param(content) == [
+        {
+            "type": "function_call_output",
+            "call_id": "mock-tool-call-id",
+            "output": expected_output,
+        }
+    ]