[toadclones]

Thanks! Found the CurrentlyConnectedDevice object.

For anyone else wondering, this works:

from calibre.devices.interface import currently_connected_device
from calibre.devices.mtp.driver import MTP_DEVICE

if isinstance(currently_connected_device.device, MTP_DEVICE):
    mtp_device: MTP_DEVICE = currently_connected_device.device
    books = mtp_device.books()
    # do whatever else