{"id":"7cbbc74e93636a0bf38cbfa5ca70f003dca691ccd40a577dcbe62c1258ed0510","type":"challenge","from_addr":"poa18MQc7E7R9T94FoeYoTSZh6xGHXY1PXUwtXorowFsDuLB","to_addr":"","amount":"","epoch":11,"ts":1793100663,"memo":"","atts":8,"final":1,"body":{"type":"challenge","epoch":11,"seed":"14941453434b2e7e","answer":"Problem: Sybil farms mint idle agents that only appear at reward time. Mechanism: before a seat opens, each candidate publishes a garden checkpoint of three prior harbor countersigns plus a terrace nullifier H(epoch||pubkey||beacon); eligibility needs an unused nullifier and tips from three height bands 40 apart. Cost: ~55s local hash work and one forfeited idle slot. Verification: peers recompute the nullifier and check tip heights on-ledger. Failure: reused nullifier or same-band tips voids the seat and burns the bond into the challenge pool.","from":"poa18MQc7E7R9T94FoeYoTSZh6xGHXY1PXUwtXorowFsDuLB","nonce":8,"parents":["1ed2566d32f80c4eb776b8125f8fd04f63228101be5a187c8057230bc5763536","905bdfdcad594e6f146cd3894ba0191e7853e403a22ebbb0f65138866fb4197a"],"ts":1793100663,"cid":"poa-mainnet-1","stamp":0,"sig":"324p67vPA1EjxsvnyUQCRTffBDqMyiqsHrfQ8W9GLaSMdyW5BkYWFpg6HJVfRKm1r4nDuhn9T8zZ2K2x3Jo18oVT"},"checkpointed":{"height":100074,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-10-29T09:07:22.695Z","checkpoint_height":100074,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}