A script and a couple of automations to allow Home Assistant to transfer todo/shopping list items from one list to another (eg. Google Keep to Todoist)

todo-list-transfer.yaml

script:
  todo_list_move_incomplete_items:
    fields:
      source_list:
        description: "Source list to copy from"
      dest_list:
        description: "Destination list to copy to"
      subtext:
        description: "The non-title text to add to the items"
      due_today:
        description: "Whether the task should have today as a due date"
        default: "False"
        #FIXME do something with this field, not in use yet
    sequence:
      - service: todo.get_items
        data:
          status:
            - needs_action
        response_variable: items
        target:
          entity_id: "{{ source_list }}"
      - repeat:
          for_each: >
            {% set list_name = items.keys() | list %}
            {{ items[list_name[0]]['items'] }}
          sequence:
            - if: 
                - alias: "Due date is set"
                  condition: template
                  value_template: "{{ due_today == 'True' }}"
              then:
                - service: todo.add_item
                  data:
                    item: >
                      {{ repeat.item.summary }}
                    description: >
                      {{ subtext }}
                    due_date: "{{ now().strftime('%Y-%m-%d') }}"
                  target:
                    entity_id: "{{ dest_list }}"
              else:
                - service: todo.add_item
                  data:
                    item: >
                      {{ repeat.item.summary }}
                    description: >
                      {{ subtext }}
                  target:
                    entity_id: "{{ dest_list }}"
            - service: todo.remove_item
              data:
                item: >
                  {{ repeat.item.summary }}
              target:
                entity_id: "{{ source_list }}"

automation:
  - alias: Todo List - Transfer Google Tasks Todo List
    id: todolist_transfer_google_tasks_todo_list
    trigger:
      - id: "regular_trigger"
        platform: state
        entity_id: todo.google_keep_to_do #Replace this with your Google Keep todo list
      - id: "fallback_trigger"
        platform: time_pattern
        minutes: "/10"
    condition:
      - alias: "List isn't empty"
        condition: not
        conditions:
          - condition: state
            entity_id: todo.google_keep_to_do #Replace this with your Google Keep todo list
            state: "0"
    action:
      - service: script.todo_list_move_incomplete_items
        data:
          source_list: todo.google_keep_to_do #Replace this with your Google Keep todo list
          dest_list: todo.inbox #Replace this with your target todo list, eg. Todoist etc.
          subtext: "Imported from Google Tasks"
          due_today: "True"

  - alias: Todo List - Transfer Google Tasks Todo List
    id: todolist_transfer_google_tasks_todo_list
    trigger:
      - id: "regular_trigger"
        platform: state
        entity_id: todo.google_keep_to_do #Replace this with your Google Keep todo list
      - id: "fallback_trigger"
        platform: time_pattern
        minutes: "/10"
    condition:
      - alias: "List isn't empty"
        condition: not
        conditions:
          - condition: state
            entity_id: todo.google_keep_to_do #Replace this with your Google Keep todo list
            state: "0"
    action:
      - service: script.todo_list_move_incomplete_items
        data:
          source_list: todo.google_keep_to_do #Replace this with your Google Keep todo list
          dest_list: todo.inbox #Replace this with your target todo list, eg. Todoist etc.
          subtext: "Imported from Google Tasks"
          due_today: "True"