diff --git a/homeassistant/components/calendar/llm.py b/homeassistant/components/calendar/llm.py
index 8000eaad1a2a..ca4afea6444a 100644
--- a/homeassistant/components/calendar/llm.py
+++ b/homeassistant/components/calendar/llm.py
@@ -10,9 +10,14 @@ from homeassistant.components.homeassistant import async_should_expose
 from homeassistant.components.llm import LLMTools
 from homeassistant.core import HomeAssistant, callback
 from homeassistant.helpers import entity_registry as er, intent
-from homeassistant.helpers.llm import LLM_API_ASSIST, LLMContext, Tool, ToolInput
+from homeassistant.helpers.llm import (
+    LLM_API_ASSIST,
+    LLMContext,
+    Tool,
+    ToolInput,
+    ToolResult,
+)
 from homeassistant.util import dt as dt_util
-from homeassistant.util.json import JsonObjectType
 
 from . import SERVICE_GET_EVENTS
 from .const import DOMAIN
@@ -40,7 +45,7 @@ class CalendarGetEventsTool(Tool):
     @override
     async def async_call(
         self, hass: HomeAssistant, tool_input: ToolInput, llm_context: LLMContext
-    ) -> JsonObjectType:
+    ) -> ToolResult:
         """Query a calendar."""
         data = self.parameters(tool_input.tool_args)
         result = intent.async_match_targets(
@@ -52,7 +57,7 @@ class CalendarGetEventsTool(Tool):
             ),
         )
         if not result.is_match:
-            return {"success": False, "error": "Calendar not found"}
+            return ToolResult(data={"error": "Calendar not found"}, error=True)
 
         entity_id = result.states[0].entity_id
         if data["range"] == "today":
@@ -82,7 +87,7 @@ class CalendarGetEventsTool(Tool):
             for event in cast(dict, service_result)[entity_id]["events"]
         ]
 
-        return {"success": True, "result": events}
+        return ToolResult(data={"events": events})
 
 
 @callback
diff --git a/tests/components/calendar/test_llm.py b/tests/components/calendar/test_llm.py
index aab77f8f7211..0cb64a47163c 100644
--- a/tests/components/calendar/test_llm.py
+++ b/tests/components/calendar/test_llm.py
@@ -107,24 +107,25 @@ async def test_calendar_get_events_tool(hass: HomeAssistant) -> None:
         "end_date_time": dt_util.start_of_local_day(now) + timedelta(days=1),
     }
 
-    assert response == {
-        "success": True,
-        "result": [
-            {
-                "start": "2025-09-17",
-                "end": "2025-09-18",
-                "summary": "Home Assistant 12th birthday",
-                "description": "",
-                "all_day": True,
-            },
-            {
-                "start": "2025-09-17T14:00:00-05:00",
-                "end": "2025-09-18T15:00:00-05:00",
-                "summary": "Champagne",
-                "description": "",
-            },
-        ],
-    }
+    assert response == llm.ToolResult(
+        data={
+            "events": [
+                {
+                    "start": "2025-09-17",
+                    "end": "2025-09-18",
+                    "summary": "Home Assistant 12th birthday",
+                    "description": "",
+                    "all_day": True,
+                },
+                {
+                    "start": "2025-09-17T14:00:00-05:00",
+                    "end": "2025-09-18T15:00:00-05:00",
+                    "summary": "Champagne",
+                    "description": "",
+                },
+            ]
+        }
+    )
 
     # The "week" range searches seven days out.
     calls.clear()
@@ -153,7 +154,7 @@ async def test_calendar_get_events_tool_not_found(hass: HomeAssistant) -> None:
         ),
         llm_context,
     )
-    assert response == {"success": False, "error": "Calendar not found"}
+    assert response == llm.ToolResult(data={"error": "Calendar not found"}, error=True)
 
 
 async def test_calendar_get_events_tool_uses_aliases(