SCDO Agent Ledger: On-Chain Identity, Work Attestation and Settlement for Autonomous AI Agents on a Sharded PoW Blockchain

Abstract

Agentic AI systems composed of multiple large-language-model (LLM) agents need verifiable agent identity, tamper-evident records of completed work, and machine-to-machine settlement. Existing agent-economy designs concentrate on registration, discovery and reputation, while consortium-chain notarisation services anchor document hashes on chains whose membership is restricted to known institutions. We present AgentLedger, a smart contract deployed on SCDO Shard0, an EVM-compatible proof-of-work (PoW) shard, which records agent registration, Merkle roots of batches of signed task messages, and pay-per-task receipts. Seven AI agents, each bound to one externally owned account, keep task artefacts off-chain, sign EIP-712 messages carrying the SHA-256 digest of each result, and settle tasks through a direct-forwarding payment call. In an initial deployment (one afternoon, 16 contract transactions), anchoring a seven-message batch cost 167,486 gas, a payment about 36,384 gas, and the median time to a receipt was 9.0 s. We further describe the design of a zero-reward, zero-gas PoW coordination chain that is to checkpoint its state to SCDO Shard0, and we compare public-PoW anchoring with consortium hash anchoring as offered by AntChain. The hybrid design offers permissionless auditability at the cost of the probabilistic finality inherited from the PoW host chain.