companion.home-assistant/docs/notifications/received.md

title	id
Notification Received	notification-received

You can receive an event when a notification is received on the device. In order to receive this event you will need to set confirmation: true as a parameter in your notification action. All notification data will be present in the event data for the event type mobile_app_notification_received. If you do not set this parameter then no event will be sent from the device when the notification is received.

Example:

automation:
  - alias: Notification received confirmation
    trigger:
      ...
    action:
      - action: notify.mobile_app_<your_device_id_here>
        data:
          message: "This notification has been received"
          data:
            confirmation: true

Example event data:

{
    "event_type": "mobile_app_notification_received",
    "data": {
        "message": "test",
        "device_id": "DEVICE_ID"
    },
    "origin": "REMOTE",
    "time_fired": "2020-10-06T05:36:12.864583+00:00",
    "context": {
        "id": "ID",
        "parent_id": null,
        "user_id": "USER_ID"
    }
}