Short version: Most AI checkout/fulfillment agents can’t actually parse or enforce your refund terms; they guess. The fix is to make refunds machine-readable end‑to‑end—from policy markup and attestations to on‑chain escrow and agent session controls—so refunds execute automatically without chargebacks or arbitration surprises.

Long version below.

How to Build Machine-Readable Refund Logic for Autonomous Agents

Hook — the headache you’re living with: Your LLM-driven “autonomous checkout” bot approves a purchase at 3:02 PM. Ten days later the buyer requests a return; your ops script can’t tell whether the product, country, carrier scans, or time window qualifies. Human review stalls, the window to fight the dispute closes, and you eat arbitration fees you never budgeted for. Meanwhile, your AA paymaster quietly bleeds because your policy caps weren’t enforced in the agent’s session, and a bundler shoved a pathological UserOp that crossed your post‑op gas limit.

Agitate — what this costs in 2026 terms:

• Arbitrating a single card dispute typically incurs network fees in the mid‑hundreds of dollars per case; merchants that escalate unnecessarily absorb avoidable losses. Mastercard’s own materials now emphasize programs to reduce first‑party (“friendly”) fraud precisely because escalations are rising globally. If you don’t adjudicate eligibility early with machine‑readable rules, avoidable escalations stack up fast. (paymentsmastery.com)
• Search visibility now expects machine-readable return policies. Google requires country scoping in

  MerchantReturnPolicy

  structured data; omitting it degrades product surfacing and confuses agents scraping your catalog. (searchenginejournal.com)
• On-chain UX moved forward in 2025: Ethereum’s Pectra upgrade (May 7, 2025) shipped EIP‑7702, letting EOAs temporarily act like smart accounts—meaning your agents can hold session‑scoped permissions and budgets without migrating users to new addresses. If your refund flow can’t exploit this (batched authorization, sponsor pays gas, policy‑limited spending), you’re behind competitors modernizing with 4337 + 7702. (blog.ethereum.org)
• Crypto refunds exist in PSP APIs but include hard constraints (e.g., post‑intent windows). If your bot doesn’t enforce those, you’ll reconcile “unsupported funds” manually. (developers.circle.com)
• AA/Paymaster risk is real. Community reports in Jan 2026 highlight an EntryPoint v0.8 failure‑path accounting edge case that can overcharge paymasters when

  postOp

  OOGs. Even as fixes land, production paymasters need explicit caps/alerts. (github.com)

Here’s the pragmatic solution we deploy at 7Block Labs: make “refundability” computable across the full path—policy, evidence, payment, and agent execution—so autonomous agents never guess.

—

Target audience (and the language they expect):

• Who: Marketplace Platform PMs, VP/Director of Ops & Risk, and Engineering Leads at retailers/fintechs adding agentic checkout and returns at 50k–500k RMAs/month, multi‑country catalogs, card + crypto rails.
• Their required keywords we bake into the plan: merchant of record (MoR), RMA automation, reverse logistics SLA, GS1‑128/SSCC labels, EDI 856/ASN timing, first‑party fraud, Rapid Dispute Resolution (issuer pre‑decision),

  MerchantReturnPolicy

  JSON‑LD with applicableCountry, Verifiable Credentials 2.0, EAS attestations, ERC‑4337 UserOperation, EIP‑7702 session delegation, paymaster policy caps, EntryPoint AA error codes, carrier scan events (Delivered/Acceptance Scan), partial refund rules, and representment evidence packages. (developers.google.com)

Solve — 7Block Labs methodology (technical, but geared to ROI)

Phase 1 — Express refund policy as machine-readable contracts

• Web policy layer:
  • Publish org‑level and offer‑level return logic with

    MerchantReturnPolicy

    under

    Organization.hasMerchantReturnPolicy

    and per‑

    Offer

    overrides. Always include

    applicableCountry

    to satisfy 2025 guidance and enable agent routing by geography. (developers.google.com)
  • Keep seasonal windows and restocking fees machine‑discoverable via

    MerchantReturnPolicySeasonalOverride

    with explicit start/end dates. (developers.google.com)
• Agent governance layer:
  • Define the same constraints as ODRL policies (rights/obligations) so agents can reason over them: allowable refund windows, evidence duties (photo, RMA scan, carrier event), and exceptions. The ODRL community advanced formal semantics and interoperability in 2025—use it to make “eligible vs. ineligible” decidable instead of free‑text. (w3.org)
  • Where identity is needed (reseller eligibility, high‑value returns), use W3C Verifiable Credentials 2.0 for machine‑verifiable claims (e.g., “Authorized Reseller,” “KYC Level Verified,” “Return Window Exception Granted”). VC 2.0 reached W3C Recommendation on May 15, 2025. (w3.org)

What you get: policy-as‑data any agent can parse, while Google and marketplaces can index correct terms per country—reducing false approvals and SEO fallout.

Phase 2 — Encode refundability into payment and contract flows

• On‑chain escrow and explicit refund semantics:
  • Use ERC‑5528 (Refundable Fungible Token) or ERC‑5507 (Refundable Token extension for ERC‑20/721/1155) when you want buyers to have a cryptographic right to refund within a declarative window. These interfaces standardize escrow,

    refund

    , and

    withdraw

    semantics and reduce bespoke logic. We adapt these patterns to stablecoin rails and RWA deposits. (eips.ethereum.org)
• Account abstraction and agent sessions:
  • Combine ERC‑4337 smart accounts with EIP‑7702 to grant agents session‑scoped powers: cap per‑refund spend, limit to approved merchants/contracts, and require specific attestations at call time. Pectra’s 7702 lets EOAs delegate to audited smart‑account code without changing addresses; wallets and bundlers already expose 7702/4337 APIs. (blockworks.co)
  • Production checklist items we implement:
    • Paymasters: enforce internal ceilings matching

      paymasterPostOpGasLimit

      and watch for AA50/AA51 conditions (postOp revert, prefund below cost). Vendor docs and community threads show the exact error surfaces and how to monitor them. (alchemy.com)
    • EntryPoint hardening: until every environment is on patched EntryPoint releases, add a “post‑op overcharge sentinel” to detect OOG failure‑path anomalies. Track Issue #606 and related release notes. (github.com)
    • Bundler APIs: adopt ERC‑7769 JSON‑RPC so wallets/agents can treat UserOps like first‑class objects (simulate, submit, trace) and your monitoring can attribute failed refunds precisely. (eips.ethereum.org)
• Off‑chain/On‑chain evidence bridge:
  • Use the Ethereum Attestation Service (EAS) to anchor refund evidence: “RMA issued,” “Carrier Delivered,” “Warehouse Received,” “Defect Confirmed.” We template schemas so agents and paymasters can require proof before releasing funds. EAS is live across mainnet and L2s with millions of attestations. (attest.org)
  • For sensitive artifacts (IDs, invoices), issue VC 2.0 credentials and supply selective‑disclosure proofs to agents/paymasters—no PII onchain, strong machine‑verifiability. (w3.org)
• Card‑network alignment (reduce chargebacks by design):
  • Feed agents “representment‑ready” evidence so disputes resolve early via issuer programs (e.g., first‑party fraud detection/compelling‑evidence initiatives) instead of drifting to arbitration. Mastercard’s 2025 expansion underscores how enhanced signals (device, delivery, identity, location) change issuer decisions; your refund policy should produce those signals automatically. (mastercard.com)
• Crypto PSP refunds:
  • Map your policy windows to PSP constraints (e.g., Circle crypto refunds only within 30 days post‑intent expiry), or the agent blocks refunds it can’t settle programmatically. (developers.circle.com)

What you get: programmable, auditable refunds the agent can execute atomically—release funds only when policy and evidence resolve as “true.”

Phase 3 — Wire in reverse‑logistics truth (RMA → ASN → receipt)

• Returns don’t exist without supply‑chain proofs. Agents consume:
  • EDI 856/ASN timing (send after carrier tender, not when the truck is still being packed), GS1‑128/SSCC scans mapped 1:1 with cartons and pallets, and HL hierarchies that match physical packing. This prevents “policy eligible but warehouse blind” outcomes that trigger chargebacks. (help.orderful.com)
  • Carrier scan events (Acceptance Scan, Delivered), ASN window discipline (typical 2–4 hours pre‑receipt), and avoidance of duplicate identifiers (BSN02, SSCC)—so the agent can decide “refund now vs. await inspection” with confidence. (blog.ezcomsoftware.com)

What you get: the agent can answer, with cryptographic and logistic evidence, whether a refund is due now, partially, later, or never.

Phase 4 — Deployable blueprints (we’ll ship these with you)

• Pattern A — “Finite window + auto‑refund on delivery”
  • Policy: finite window per

    applicableCountry

    ; ODRL duty = provide photo + RMA; VC 2.0 credential “Original Buyer.”
  • Contract: ERC‑5528 stablecoin escrow; release or refund based on EAS “Delivered + Received” attestations; partial refund if “Opened but resellable.”
  • Agent: 7702 session delegation to a minimal account for the initial purchase; subsequent refund via ERC‑4337 UserOp sponsored by a capped paymaster.
• Pattern B — “Digital license cooling‑off”
  • Policy: 14‑day cooling‑off, auto‑invalidate license on refund.
  • Contract: ERC‑5507 extension on the license NFT;

    refundDeadlineOf

    uses blocks for determinism; burn on refund and release escrow.
  • Agent: denies refund if “License used > N sessions” per on‑chain usage attestations.
• Pattern C — “Risk‑bounded AI buyer”
  • Policy: MoR sets per‑agent budgets, merchant allowlist, and “refund authority up to $X per week.”
  • Contract: 7702 for atomic first buy; agent then operates under 4337 session keys. Paymaster enforces caps and requires EAS “Refund Eligibility Check: pass=true” before sponsoring a refund UserOp.
  • Monitoring: ERC‑7769 endpoints feed dashboards; alarms on AA50/AA51 and any

    postOp

    overcharge sentinel.

Implementation plan (8–12 weeks to value)

• Week 0–2: Policy ingestion and modeling
  • Convert T&Cs into

    MerchantReturnPolicy

    + ODRL profile; publish JSON‑LD; index tests in Search Console. We deliver audit trails so Legal signs off. (developers.google.com)
• Week 3–6: Contract + agent rail
  • Stand up escrow/refund contracts (ERC‑5528/5507 variants), EAS schemas, and 7702/4337 session integrations. Harden paymaster and add the overcharge sentinel; wire ERC‑7769 RPC to your observability stack. (eips.ethereum.org)
• Week 7–8: RMA/ASN evidence bridge
  • Map WMS/EDI (856/ASN) fields to attestations; create “Delivered/Received/Inspected” proofs and reconcile with carrier scans and SSCC hierarchies. (boldvan.com)
• Week 9–12: Sandboxes + PSPs
  • Wire card networks’ enhanced signals (device, delivery, identity) for first‑party fraud mitigation; map crypto PSP refund windows; dry run five return scenarios per country. (mastercard.com)

Technical specs we standardize (so agents stop guessing)

• Policy and discovery
  • JSON‑LD

    MerchantReturnPolicy

    (org + offer), with

    applicableCountry

    and seasonal overrides.
  • ODRL profile: actions=return/refund; constraints=days‑since‑delivery, country, condition; duties=evidence artifacts. (developers.google.com)
• Identity and evidence
  • VC 2.0 credentials for buyer/merchant claims; EAS attestations for all refund milestones. (w3.org)
• Smart contracts
  • ERC‑5528/5507 escrow + refund primitives; 7702 delegation for atomic session setup; 4337 EntryPoint v0.8+/v0.9 with hardened paymaster. (eips.ethereum.org)
• Monitoring + safety
  • ERC‑7769 RPC, AAxx error tracking (AA50/AA51), and

    postOp

    overcharge sentinel with auto‑throttle on suspected bundles. (eips.ethereum.org)
• Supply‑chain integration
  • EDI 856/ASN timing and GS1‑128/SSCC mapping to cartons/pallets; carrier scan hooks. (help.orderful.com)

Practical example — “EU physical goods, card + USDC, 30‑day window”

• Policy: 30‑day from delivery, unopened = full refund; opened = 85%; exceptions: DOA items full within 14 days;

  applicableCountry

  = DE, FR, NL.
• Web: publish JSON‑LD with seasonal override for November peak; agents see country scoping at crawl‑time. (developers.google.com)
• Identity: upon RMA request, issue VC 2.0 “Original Buyer (order#, SKU, timestamp).” (w3.org)
• Evidence: EAS attestation chain — “RMA Issued,” “Carrier Acceptance,” “Delivered,” “Warehouse Received,” “Inspection: unopened/defect code.”
• Contracts:
  • USDC escrow via ERC‑5528;

    escrowRefund

    on EAS “Inspection: unopened=true.”
  • Partial refunds: compute 85% in contract with policy hash bound to the attestation; RWA tax handling off‑chain, posted as EAS note.
• Agent session: buyer’s wallet signs a 7702 delegation for checkout; the marketplace’s agent triggers a sponsored 4337 UserOp for refund once EAS signals are green.
• Dispute off‑ramp: if card dispute opens, the issuer gets device + delivery + identity signals (logistics + VC + EAS) to avoid arbitration. (mastercard.com)

Emerging best practices we recommend now

• Always provide

  applicableCountry

  and explicit delivery‑based clocks; agents will misread vague “30 days” policies. (searchenginejournal.com)
• Favor block‑based deadlines in contracts (e.g., ERC‑5507 uses block numbers) to avoid timestamp drift when agents batch actions. (eips.ethereum.org)
• Treat 7702 as the “first transaction bootstrap,” then use 4337 session keys for ongoing automations; it’s the path Pectra unlocked for mainstream wallets. (blockworks.co)
• Harden paymasters: clamp gas on

  postOp

  failure paths; alert on anomalies; keep an upgrade plan aligned to EntryPoint releases. Track open issues like #606. (github.com)
• Tie RMA → ASN → receipt state into attestations; agents should not refund on “label created”; wait for “Acceptance Scan” or facility receipt in evidence. (help.orderful.com)

GTM metrics — prove this in your dashboard

• Time‑to‑refund (TTR) P50/P95 by country and SKU class.
• “Agent‑autonomous refunds” share vs. manual; goal >70% in 90 days without increased leakage.
• Chargebacks as % of refunds; target a measurable drop after issuer‑signal integration (delivery, device, identity). (mastercard.com)
• Arbitration rate and average arbitration cost avoided (trackable via issuer outcomes and finance ledger). (chargebackstop.com)
• Paymaster loss ratio: sponsored refund gas vs. budget cap; zero over-cap events after sentinel deployment.
• ASN compliance rate (duplicate SSCCs, BSN02 collisions) and refund delays tied to ASN mismatches. (boldvan.com)

Where 7Block Labs fits (and what you can click into now)

• Need policy-to-contract execution with deliverables your CFO will sign? Our team ships production systems that agents can call safely.
  • See our custom blockchain development services for escrow/refund contracts and AA integrations.
  • If you’re starting from web policy, our web3 development services team will publish compliant JSON‑LD and ODRL profiles wired to your catalog and returns portal.
  • Worried about paymasters and EntryPoint nuances? Our security audit services include AA/7702 hardening and live runbooks for ERC‑7769 telemetry.
  • Need to glue PSPs, EDI, and attestations? Our blockchain integration practice connects WMS/EDI 856/ASN, carrier scans, PSP refund APIs, EAS, and VC wallets.

Closing thought: Refund logic isn’t a paragraph in your T&Cs anymore; it’s a machine interface your agents, wallets, issuers, and smart contracts will interrogate in milliseconds. If you don’t make it computable, someone else will—usually your acquirer or a fraudster.

Personalized CTA: If you’re the VP of Ops or the Platform PM at a marketplace handling 50k+ RMAs/month across at least three countries—and you’ve been tasked to “cut chargebacks by 25% and move 60% of refunds to autonomous execution by Q3 2026”—reply with “Refund‑Agents” and we’ll run a 10‑day Policy‑to‑Contract sprint: live

MerchantReturnPolicy

+ ODRL profile, an EAS schema set, and a 7702/4337 refund pilot wired to your sandbox. We’ll show your CFO the TTR and arbitration‑avoidance deltas on real orders in two weeks—or we’ll finish the backlog for you with our custom blockchain development services and blockchain integration team.