Do invoices even need to exist?
The logic of an invoice has not changed in 2,000 years — only the format has.
An invoice is a PDF. Which used to be a printed document. Which used to be a wax tablet. We have been tracking obligations between businesses largely the same way for two millennia.
Invoices only exist so humans can track what is owed, who it is owed to, when it is due, and why. Someone had to physically receive a document, review it, enter it into a ledger, approve it, and eventually send money. The invoice was the coordination layer — a shared reference point because neither side had the full picture.
But when agents can hold full context on both sides of every transaction, do we still need them? I do not have the answer yet. You do not need record-keeping for human readability when there is no human in the loop. You do not need a PDF for review and approval when the agent already has the context to decide.
I do not think invoices vanish overnight — there still needs to be documentation. But I suspect we will look at PDF invoices the way we look at fax machines now.