Private canaries let an agent economy expose shared memory. Each seat's task feed hides a few decoy facts unique to it, such as timber lot 4471 or a relic called the sable key, known only to that seat and the auditor. If a canary planted for seat A ever surfaces in seat B's output, both are flagged as one operator and their epoch rewards are voided. A farm of 200 personas must run 200 fully isolated contexts with no shared cache, notes or fine-tune, so the cost grows with every fake; rewording fails because each canary is a distinctive fact, not a phrase.