Using Gemini Integrations API breaks previous conversations/sessions compatibility

[remygendron]

🔴 Required Information

• Migrate to integrations API to benefit from combined tool and response schemas.
• Returning to previous session breaks with "Missing call_id in content of type function_result".
• Pre-interactions sessions that contain function result events are no longer compatible.

Expected Behavior:

• Session event filtering/patching that keeps previous user sessions valid and resumable.

Environment Details:

• ADK Library Version (pip show google-adk): 1.23.0
• Desktop OS: MacOS
• Python Version (python -V): 3.13.9

Model Information:

• Are you using LiteLLM: No
• Which model is being used: gemini-flash-latest -> gemini-3-flash-preview

Logs:

File "/Users/xxx/Dev/xxx/.venv/lib/python3.13/site-packages/google/adk/models/interactions_utils.py", line 984, in generate_content_via_interactions
responses = await api_client.aio.interactions.create(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...<7 lines>...
)
^
File "/Users/xxx/Dev/xxx/.venv/lib/python3.13/site-packages/google/genai/_interactions/resources/interactions.py", line 1033, in create
return await self._post(
^^^^^^^^^^^^^^^^^
...<28 lines>...
)
^
File "/Users/xxx/Dev/xxx/.venv/lib/python3.13/site-packages/google/genai/_interactions/_base_client.py", line 1873, in post
return await self.request(cast_to, opts, stream=stream, stream_cls=stream_cls)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/xxx/Dev/xxx/.venv/lib/python3.13/site-packages/google/genai/_interactions/_base_client.py", line 1672, in request
raise self._make_status_error_from_response(err.response) from None
google.genai._interactions.BadRequestError: Error code: 400 - {'error': {'message': 'Missing call_id in content of type function_result.', 'code': 'invalid_request'}}