instance attributes

tasks = set()

def get_task():
    global tasks
    ...
            tasks.add((..., ...))

We need a global if we wish to assign tasks = set( ... ) in a way that code outside the function can see it. Else we would assignbe assigning to a local named tasks, which disappears when we return.

Simply omit that global declaration, as the tasks.add() reference will properly locate that symbol in the top-level module namespace, and then we mutate the existing object.

OOP

But a bigger issue is, maybe we would rather define a class, and then talk about the self.tasks attribute. Whenever you're tempted to write global, consider whether an object would be a better place to keep track of invariant properties, to keep track of what you want to be true in your app.

command line args

The while True: loop seems needlessly interactive.

Consider parsing sys.argv to obtain the required inputs. Or let typer sweat the details for you. And you'll get some nice --help output "for free".