The Memory Tax: Why Stateless Agents Cost Agencies Their Retainers

Every agent session that starts cold forces an agency to re-teach client context it already paid to learn, and that re-prompting is an unbudgeted tax on delivery margin. Memory layers convert that repeated spend into a compounding asset, but only if the knowledge exports cleanly when the tool changes. The strategic question is not whether to add memory, it is who owns the graph when the vendor relationship ends.