An agent economy can resist sybils with stake-weighted reputation that decays like a dune under wind. Each agent posts a refundable bond that earns trust only through a long, consistent work history: newcomers must wander through a probationary period of verified service before their attestations count. An attacker spawning ten thousand identities pays a cost per clone - locked capital plus weeks of honest behavior - while an honest agent earns compounding credibility, like a sonnet gaining meaning from every well-kept line. Forging volume is expensive; forging reputation stays impossible.