peaq ERC-8004 Escrow

This page is the real-life example of the ERC-8004 agent lifecycle described in the introduction. This flow lets a buyer machine (Unitree) and a seller machine (Drone) register identities on peaq, create and accept a service claim on peaq, fund the claim from Base (USDT locked in a Base escrow), and then release payment on Base while peaq is kept in sync via LayerZero messages.

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Actors & Contracts

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Actors

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Key Components

peaq

• Identity / registration — register(agent-card.json) → creates machine/agent identity (agent_id)
• ClaimRegistry — creates/accepts claims, locks stakes, tracks status
• PaymentReceiver — receives LayerZero messages (lzReceive) and updates peaq state
• TransactionRegistry — records funding/release events (auditability)

Base

• BaseEscrow — locks USDT, releases USDT to seller, emits cross-chain messages

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Phase 1 — Identity registration on peaq

Goal: Both parties become on-chain actors on peaq.

1. Unitree → peaq: register("unitree-agent-card.json")
   peaq → Unitree: agent_id
2. Drone → peaq: register("drone-agent-card.json")
   peaq → Drone: agent_id

Result: Both buyer and seller have peaq identities and can participate in claims.

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Phase 2 — Create & accept claim on peaq

Goal: Create a service purchase intent on peaq and have the seller accept it with stake.

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Buyer (Unitree)

1. Ensure buyer has USDC on peaq for stake (mint if needed).
2. Approve staking: approve(ClaimRegistry, stake).
3. Ensure buyer has USDT on Base (mint if needed).
4. Create the claim on peaq:
   create_purchase_claim(seller=Drone, service_id, amount, deadline)
   peaq → Unitree: claim_id
5. Share claim_id to Drone (off-chain / manual in this diagram).

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Seller (Drone)

6. Fetch details: get_claim(claim_id).
7. Verify claim + seller address (local checks).
8. Ensure seller has USDC on peaq for stake (mint if needed).
9. Approve staking: approve(ClaimRegistry, stake).
10. Accept claim: accept_claim(claim_id)
    peaq: locks seller stake
    peaq → Drone: status Accepted.

Result: Claim exists and is accepted; both sides can poll status on peaq.

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Phase 3 — Cross-chain funding (Base → peaq)

Goal: Lock funds in Base escrow and mark the claim as Funded on peaq via LayerZero.

1. Unitree → peaq: get_claim(claim_id) (to confirm deadline).
2. Unitree → Base: approve(BaseEscrow, USDT amount).
3. Unitree → Base: BaseEscrow.deposit(claim_id, amount, seller, deadline)
   BaseEscrow: locks USDT.
4. Base → LayerZero: sends cross-chain “funded” message.
5. LayerZero → peaq: delivers to PaymentReceiver.
6. peaq.PaymentReceiver: lzReceive()
   • updates TransactionRegistry
   • updates claim status → Funded.

Result: Funds are escrowed on Base; peaq reflects “Funded”.

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Phase 4 — Release payment on Base + finalize on peaq

Goal: Seller performs the service off-chain; buyer releases escrowed payment; peaq finalizes status and returns stakes.

1. Drone: Performs the real-world service (off-chain).
2. Unitree → Base: BaseEscrow.release(claim_id)
   BaseEscrow: transfers USDT to Drone
   Base → Drone: USDT received.
3. Base → LayerZero: sends “completed” message.
4. LayerZero → peaq: delivers completion to PaymentReceiver.
5. peaq.PaymentReceiver:
   • updates TransactionRegistry
   • updates claim status → Completed
   • returns stakes to buyer & seller.

Result: Payment settled on Base; peaq records completion and settles stakes.

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State machine (peaq claim status)

Created → Accepted → Funded → Completed

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What to poll / verify

• Buyer & Seller poll on peaq: get_claim(claim_id) to read status + deadline.
• Funding truth lives on Base: USDT is locked/released by BaseEscrow.
• peaq is the coordination ledger: identity, claim lifecycle, audit trail, stake settlement.
• LayerZero is the sync bridge: delivers funding + completion events to peaq.

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Outcome

A single claim ties together:

• Identity + staking + lifecycle on peaq
• USDT custody + payout on Base
• Cross-chain state synchronization via LayerZero

Transaction is complete when Base pays out and peaq marks Completed and returns stakes.

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Contract addresses

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peaq

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LayerZero (peaq)

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Base