Executive Summary

The problem in one paragraph

Agricultural lots are the largest class of physical assets without an interoperable on-chain form. Existing token standards cover the two ends of the problem: ERC-3643 standardizes permissioned securities on ERC-20, and ERC-7943 (Final, May 2026) standardizes the enforcement surface every real-world-asset token needs. Traceability regimes such as GS1 EPCIS 2.0, the FDA Food Traceability Rule (FSMA 204) and the EU Deforestation Regulation (EUDR) define what must be recorded about a lot. None of them lets a token be a lot: with a production date, a unit, an origin reference, a lifecycle, and — above all — the ability to be split, merged and processed into other lots while keeping its provenance.

The standard in one paragraph

A-REX Core is a small, extensible extension of ERC-1155: the normative core is deliberately minimal so that it can be adopted, and it scales through what it leaves open (codes, hooks, attestations, lineage) rather than through what it prescribes. A conformant token implements four small interfaces:

Everything agricultural that is not the identity or the lineage of a batch — decay curves, seasonal windows, delivery workflows, oracles, carbon accounting, insurance — is out of the standard. It lives in hooks and companion contracts that demonstrate the interfaces, exactly as T-REX's compliance modules demonstrate ERC-3643 without being part of it.

Five design rules

1. No closed enumerations. Commodities, units, statuses and attestation topics are open codes. Adding quinoa, a Brazilian grading scheme or a new sustainability label never requires a redeploy.
2. No personal data on-chain. The origin of a batch is a hash or a reference (an EUDR due-diligence statement number, a warehouse receipt id, a truncated geohash), never a plot coordinate. This follows the European Data Protection Board's 2026 guidelines on blockchain.
3. Pre-harvest is first-class. A batch with producedAt == 0 is a future lot — the object of a crop receivable, a forward or a warrant.
4. Status is authority, not balance. Only a role can change a batch's lifecycle status; holding one kilogram of a lot grants nothing over the lot.
5. Lineage is mandatory. transform burns inputs, mints outputs and records parents. It maps one-to-one to an EPCIS TransformationEvent, which is what a recall, a transformation critical tracking event under FSMA 204, or a mass-balance audit needs.

Legal positioning

A-REX takes no position on whether a token issued with it is a security, a commodity, a crypto-asset under MiCA, a certificate of deposit or a receivable. That depends on how the token is offered and what it represents, not on the interface — the Howey test itself arose from citrus groves sold to passive investors. The standard therefore ships the enforcement surface that every classification requires (freeze, forced transfer, eligibility, pause, auditable events) and leaves policy to hooks and to the issuer's counsel. The regulatory chapter gives dates verified in September 2026: FSMA 204 compliance on 20 July 2028; EUDR application on 30 December 2026 (medium and large operators) and 30 June 2027 (micro and small); MiCA fully applicable since 30 December 2024; EDPB blockchain guidelines final since July 2026.

What exists today

• A normative text in ERC format (standard/AREX-CORE.md, CC0) and the Solidity interfaces (contracts/standard/, CC0).
• A reference implementation (ARexToken, ARexAttestations, MIT): UUPS upgradeable, ERC-7201 storage, role-based access control, reentrancy-locked hook pipeline, 24.1 KB (under the EIP-170 limit).
• Reference hooks: eligibility (allow/block/sanctions with source and TTL), expiry, attestation requirements per commodity, perishability decay models, seasonal windows, delivery custody and settlement, and EPCIS-shaped traceability.
• Companion extensions: a deterministic commodity price oracle, a wrapper for registry-immobilised carbon credits (attestation, never issuance), and attestation-triggered parametric insurance.
• Tests: 42 on the reference implementation, hooks and extensions (including a seeded randomized invariant test); continuous integration; pinned dependencies; a JSON Schema for batch metadata aligned with EPCIS 2.0 and FSMA 204 key data elements.
• Engineering documentation in system-design form: a System Design Document with component, data, interaction and operational models, sixteen architectural decision records, a requirements traceability matrix and an audit-readiness package.

What A-REX is not

• Not a farm registry, not an identity system, not an oracle network. Those are integrations, chosen by the issuer.
• Not a valuation engine. The core has no notion of price or decay; a hook or an off-chain service provides it.
• Not a carbon registry. Carbon credits can be referenced and gated by attestations; issuing them is the registry's job.
• Not an ERC yet. The interfaces will be submitted to ethereum/ERCs only after a production deployment, independent hook implementations and a third-party audit, because an ERC freezes what it standardizes.

How it becomes a standard

ERC-3643 was in production for three years before its EIP, and its Final status followed adoption rather than causing it. ERC-7943 went from draft to Final in eight months with a six-function interface and a coalition of implementers. A-REX follows the same path: freeze a small interface, ship a working reference, prove it with real lots, gather independent implementers, then submit. The roadmap is in the Future Developments chapter.

Reading guide

• Decision makers: this chapter, Solution Overview, Regulatory Compliance, Use Cases.
• Engineers: Technical Specification, Core Standard, Hooks and Reference Modules, Implementation Guide, Security Framework.
• Integrators and regulators: Interoperability, Regulatory Compliance, Appendix A.