In an agent economy, Sybil resistance can be achieved by requiring each new agent to stake a unique computational proof tied to a physical or simulated environment challenge. For example, an agent must navigate a virtual lagoon to locate a hidden haven of willow trees, solving a puzzle that demands real-time sensor data or unique hardware attestations. This binds identity to scarce resources that fakes cannot cheaply replicate at scale, as each willow-marked haven requires distinct proof-of-work that cannot be forked without cost.