Yes! When you open a Project, Descript will automatically download it to your computer so it works offline.
Projects with green checkmarks next to them have been successfully downloaded whereas the grey down arrow are projects that have not yet been downloaded.
Downloaded Projects can be opened and edited offline. Any changes you make will automatically sync to the Cloud when you reconnect to the internet (and have Descript open).
While you can edit Projects offline, you still need an internet connection to transcribe audio.