From 9fa5a843cbf729252cc8248ca2f975b42e23d231 Mon Sep 17 00:00:00 2001
From: Denis Shulyaka <Shulyaka@gmail.com>
Date: Sun, 8 Feb 2026 00:13:57 +0300
Subject: [PATCH] Fix JSON serialization of datetime objects in Google
 Generative AI tool results (#162495)

---
 .../entity.py                                 | 15 +++++-
 .../snapshots/test_conversation.ambr          | 51 +++++++++++++++++++
 .../test_conversation.py                      | 43 +++++++++++++++-
 3 files changed, 107 insertions(+), 2 deletions(-)

diff --git a/homeassistant/components/google_generative_ai_conversation/entity.py b/homeassistant/components/google_generative_ai_conversation/entity.py
index f04b46dee96..e223d34d28b 100644
--- a/homeassistant/components/google_generative_ai_conversation/entity.py
+++ b/homeassistant/components/google_generative_ai_conversation/entity.py
@@ -7,6 +7,7 @@ import base64
 import codecs
 from collections.abc import AsyncGenerator, AsyncIterator, Callable
 from dataclasses import dataclass, replace
+import datetime
 import mimetypes
 from pathlib import Path
 from typing import TYPE_CHECKING, Any, Literal, cast
@@ -181,13 +182,25 @@ def _escape_decode(value: Any) -> Any:
     return value
 
 
+def _validate_tool_results(value: Any) -> Any:
+    """Recursively convert non-json-serializable types."""
+    if isinstance(value, (datetime.time, datetime.date)):
+        return value.isoformat()
+    if isinstance(value, list):
+        return [_validate_tool_results(item) for item in value]
+    if isinstance(value, dict):
+        return {k: _validate_tool_results(v) for k, v in value.items()}
+    return value
+
+
 def _create_google_tool_response_parts(
     parts: list[conversation.ToolResultContent],
 ) -> list[Part]:
     """Create Google tool response parts."""
     return [
         Part.from_function_response(
-            name=tool_result.tool_name, response=tool_result.tool_result
+            name=tool_result.tool_name,
+            response=_validate_tool_results(tool_result.tool_result),
         )
         for tool_result in parts
     ]
diff --git a/tests/components/google_generative_ai_conversation/snapshots/test_conversation.ambr b/tests/components/google_generative_ai_conversation/snapshots/test_conversation.ambr
index c8b1dd93be4..0e619fff902 100644
--- a/tests/components/google_generative_ai_conversation/snapshots/test_conversation.ambr
+++ b/tests/components/google_generative_ai_conversation/snapshots/test_conversation.ambr
@@ -1,6 +1,57 @@
 # serializer version: 1
 # name: test_function_call
   list([
+    Content(
+    parts=[
+      Part(
+        text='What time is it?'
+      ),
+    ],
+    role='user'
+  ),
+    Content(
+    parts=[
+      Part(
+        function_call=FunctionCall(
+          args={},
+          name='HassGetCurrentTime'
+        )
+      ),
+    ],
+    role='model'
+  ),
+    Content(
+    parts=[
+      Part(
+        function_response=FunctionResponse(
+          name='HassGetCurrentTime',
+          response={
+            'data': {
+              'failed': [],
+              'success': [],
+              'targets': []
+            },
+            'response_type': 'action_done',
+            'speech': {
+              'plain': {<... 2 items at Max depth ...>}
+            },
+            'speech_slots': {
+              'time': '16:24:17.813343'
+            }
+          }
+        )
+      ),
+    ],
+    role='user'
+  ),
+    Content(
+    parts=[
+      Part(
+        text='4:24 PM'
+      ),
+    ],
+    role='model'
+  ),
     Content(
     parts=[
       Part(
diff --git a/tests/components/google_generative_ai_conversation/test_conversation.py b/tests/components/google_generative_ai_conversation/test_conversation.py
index 833b6eaefb6..5d0cd708d46 100644
--- a/tests/components/google_generative_ai_conversation/test_conversation.py
+++ b/tests/components/google_generative_ai_conversation/test_conversation.py
@@ -1,5 +1,6 @@
 """Tests for the Google Generative AI Conversation integration conversation platform."""
 
+import datetime
 from unittest.mock import AsyncMock, patch
 
 from freezegun import freeze_time
@@ -8,7 +9,11 @@ import pytest
 from syrupy.assertion import SnapshotAssertion
 
 from homeassistant.components import conversation
-from homeassistant.components.conversation import UserContent
+from homeassistant.components.conversation import (
+    AssistantContent,
+    ToolResultContent,
+    UserContent,
+)
 from homeassistant.components.google_generative_ai_conversation.entity import (
     ERROR_GETTING_RESPONSE,
     _escape_decode,
@@ -17,6 +22,7 @@ from homeassistant.components.google_generative_ai_conversation.entity import (
 from homeassistant.const import CONF_LLM_HASS_API
 from homeassistant.core import Context, HomeAssistant
 from homeassistant.helpers import intent
+from homeassistant.helpers.llm import ToolInput
 
 from . import API_ERROR_500, CLIENT_ERROR_BAD_REQUEST
 
@@ -87,6 +93,41 @@ async def test_function_call(
     agent_id = "conversation.google_ai_conversation"
     context = Context()
 
+    # Add some pre-existing content from conversation.default_agent
+    mock_chat_log.async_add_user_content(UserContent(content="What time is it?"))
+    mock_chat_log.async_add_assistant_content_without_tools(
+        AssistantContent(
+            agent_id=agent_id,
+            tool_calls=[
+                ToolInput(
+                    tool_name="HassGetCurrentTime",
+                    tool_args={},
+                    id="01KGW7TFC1VVVK7ANHVMDA4DJ6",
+                    external=True,
+                )
+            ],
+        )
+    )
+    mock_chat_log.async_add_assistant_content_without_tools(
+        ToolResultContent(
+            agent_id=agent_id,
+            tool_call_id="01KGW7TFC1VVVK7ANHVMDA4DJ6",
+            tool_name="HassGetCurrentTime",
+            tool_result={
+                "speech": {"plain": {"speech": "4:24 PM", "extra_data": None}},
+                "response_type": "action_done",
+                "speech_slots": {"time": datetime.time(16, 24, 17, 813343)},
+                "data": {"targets": [], "success": [], "failed": []},
+            },
+        )
+    )
+    mock_chat_log.async_add_assistant_content_without_tools(
+        AssistantContent(
+            agent_id=agent_id,
+            content="4:24 PM",
+        )
+    )
+
     messages = [
         # Function call stream
         [