La Kroisette

The core of this project is 'La Kroisette', the omnichain arbitration infrastructure that we built with LayerZero to allow Kleros to serve as an optimistic oracle powering prediction market, DAO governance and escrow use cases in all the chains supported by LayerZero. We also built a vibe-coded companion app called 'Optikle' to make it easier to understand how this oracle's question asking and arbitration functionalities work.

The landing page can be seen at: https://la-kroisette-website.vercel.app

Part 1: LA KROISETTE - OMNICHAIN ARBITRATION INFRASTRUCTURE

PROJECT OVERVIEW La Kroisette is a revolutionary omnichain arbitration system that bridges decentralized oracle disputes across all LayerZero-supported blockchains with professional arbitrators on Arbitrum. Built on LayerZero's OApp framework, it creates the first truly decentralized, cross-chain dispute resolution infrastructure for the Web3 ecosystem.

PROBLEM STATEMENT The Cross-Chain Dispute Resolution Challenge: Today's decentralized ecosystem faces a fundamental mismatch: Reality.eth oracles operate on 50+ different blockchains, while Kleros arbitrators are primarily deployed on Arbitrum. This creates several critical issues:

• Users can't resolve oracle disputes when their questions live on different chains than the arbitrators
• DAOs operating across multiple chains have no unified dispute resolution mechanism
• Prediction markets are limited to same-chain arbitration, reducing their effectiveness
• Cross-chain escrow and DeFi disputes require expensive and complex manual bridging solutions
• Each blockchain essentially operates its own isolated justice system

Current State: The existing approach requires users to manually bridge funds, navigate multiple interfaces, and coordinate complex multi-step processes across chains. This friction prevents many disputes from being resolved properly, undermining trust in cross-chain applications.

SOLUTION: OMNICHAIN ARBITRATION BRIDGE La Kroisette creates a seamless bridge between Reality.eth oracles (on any LayerZero-supported chain) and Kleros v2 arbitrators (on Arbitrum), enabling users to resolve disputes across chains as if they were on a single blockchain.

KEY INNOVATION: FIVE-MESSAGE ARBITRATION PROTOCOL Our system implements a sophisticated cross-chain communication protocol with five distinct message types:

• ARBITRATION_REQUEST: Oracle chain to Arbitrum (initiate dispute)
• ARBITRATION_ACKNOWLEDGEMENT: Arbitrum to Oracle chain (confirm receipt)
• ARBITRATION_CANCELATION: Arbitrum to Oracle chain (handle rejections)
• ARBITRATION_FAILURE: Arbitrum to Oracle chain (notify failures)
• ARBITRATION_ANSWER: Arbitrum to Oracle chain (deliver final ruling)

TECHNICAL ARCHITECTURE

CORE COMPONENTS

RealitioHomeProxyLZ (Oracle Chains)

• Interfaces with Reality.eth contracts on any LayerZero-supported chain
• Handles arbitration requests from users
• Manages cross-chain communication with foreign proxy
• Processes final rulings and submits to Reality.eth

RealitioForeignProxyLZ (Arbitrum)

• Interfaces with Kleros v2 arbitration system
• Creates disputes using modern dispute templates
• Manages arbitration lifecycle and ruling collection
• Handles cross-chain ruling delivery

LayerZero Integration

• Built on OApp framework with OAppOptionsType3
• Implements sophisticated message routing and validation
• Provides atomic cross-chain operations with rollback capabilities
• Handles fee management and gas optimization

ADVANCED FEATURES

• Kleros v2 Integration
• Modern dispute template system
• Streamlined arbitration without complex appeal mechanisms
• Professional arbitrator network
• Transparent ruling process Error Handling & Recovery
• Try/catch message decoding preventing malformed message failures
• Automatic failure notifications with cross-chain rollback
• Deposit recovery mechanisms protecting user funds
• Multi-chain transaction atomicity State Synchronization
• Real-time dispute status tracking across chains
• Consistent data between oracle questions and arbitration disputes
• Automatic state updates based on cross-chain events

USE CASES & REAL-WORLD APPLICATIONS DAO GOVERNANCE DISPUTES

• Cross-chain voting disputes: Governance decisions on Polygon disputed via Arbitrum arbitrators
• Multi-chain treasury management: Spending proposals across different chains resolved through arbitration
• Cross-chain proposal validation: Ensuring governance proposals meet criteria across multiple networks PREDICTION MARKETS & ORACLES
• Omnichain prediction markets: Polymarket-style betting on any chain with unified dispute resolution
• Cross-chain oracle validation: Sports betting results on any chain verified through professional arbitrators
• Multi-chain event outcomes: Political predictions across different networks with centralized arbitration DEFI & FINANCIAL SERVICES
• Cross-chain escrow resolution: Freelancer payments on Base disputed via Arbitrum arbitrators
• Multi-chain marketplace disputes: NFT sales on different chains resolved through unified arbitration
• Cross-chain lending disputes: Loan defaults on one chain resolved via arbitrators on another
• Insurance claims: Coverage disputes across different networks with professional resolution

ENTERPRISE APPLICATIONS

• Cross-chain service agreements: Disputes over deliverables spanning multiple networks
• Multi-chain supply chain: Arbitration for logistics disputes across different blockchain networks
• Cross-chain identity verification: Arbitrated KYC processes spanning multiple chains

TECHNICAL SPECIFICATIONS MESSAGE FLOW EXAMPLE

• User requests arbitration on Polygon
• HomeProxy notifies Reality.eth contract
• LayerZero routes ARBITRATION_REQUEST to Arbitrum
• ForeignProxy creates Kleros dispute
• Arbitrators provide ruling
• LayerZero routes ARBITRATION_ANSWER back to Polygon
• HomeProxy submits ruling to Reality.eth

INNOVATION & IMPACT TECHNICAL INNOVATION

• First omnichain arbitration system bridging 50+ blockchains
• Advanced LayerZero OApp implementation with five message types
• Production-ready Kleros v2 integration with modern dispute templates
• Atomic cross-chain operations with comprehensive error handling BUSINESS IMPACT
• Unified dispute resolution across all major blockchains
• Reduced fragmentation in decentralized justice systems
• Lower costs through shared arbitration infrastructure
• Enhanced user experience with seamless cross-chain operations ECOSYSTEM BENEFITS
• Enables cross-chain DAOs with unified dispute resolution
• Supports omnichain DeFi with professional arbitration
• Facilitates multi-chain applications with trusted dispute resolution
• Creates network effects through shared arbitration infrastructure

DEPLOYMENT & SCALABILITY CURRENT DEPLOYMENT

• Arbitrum Sepolia: Foreign proxy with Kleros v2 integration
• Ethereum Sepolia: Home proxy for Reality.eth integration
• LayerZero Testnet: Cross-chain messaging infrastructure PRODUCTION READINESS
• Upgradeable contracts for future enhancements
• Gas-optimized messaging for cost-effective operations
• Comprehensive testing with foundry and hardhat
• Security audits prepared for mainnet deployment SCALABILITY FEATURES
• Horizontal scaling across all LayerZero-supported chains
• Efficient message routing with intelligent payload encoding
• Batch processing capabilities for high-volume disputes
• Fee optimization for cost-effective cross-chain operations

WHY LA KROISETTE MATTERS La Kroisette solves a practical problem that exists today: oracle disputes happen on one chain, but the best arbitrators are on another. Instead of forcing users to navigate complex manual processes or accept suboptimal local arbitration, our system makes cross-chain dispute resolution as simple as a single transaction. The result is immediate value for existing applications - DAOs can operate across chains with unified dispute resolution, prediction markets can tap into professional arbitrators regardless of which chain they're on, and DeFi protocols can offer better dispute resolution to their users. By building on LayerZero's proven infrastructure and integrating with established systems like Reality.eth and Kleros v2, La Kroisette provides a production-ready solution that works with today's multi-chain ecosystem rather than waiting for it to consolidate.

Part 2: OPTIKLE - A VIBE-CODED REALITY.ETH INTERFACE

To demonstrate La Kroisette, we vibe coded Optikle, a sophisticated interface that merges optimistic oracle functionality with cross-chain arbitration in one seamless experience. Optikle serves as the user-facing gateway to showcase how La Kroisette's three-layer integration creates a new paradigm for decentralized dispute resolution.

WHAT OPTIKLE REPRESENTS Optikle is a next-generation Reality.eth interface that transforms the traditional oracle experience into something far more powerful. Unlike the utilitarian reality.eth.limo interface, Optikle was designed from the ground up to demonstrate how interoperable dispute resolution can be both technically sophisticated and intuitively accessible.

THE UNIFIED EXPERIENCE Through Optikle, users experience the full La Kroisette ecosystem in action: question creation on any supported chain (demonstrated with Sepolia), cross-chain bridge visualization as arbitration requests flow seamlessly across chains via LayerZero v2, integrated arbitration to request and track Kleros arbitration without leaving the interface, and real-time status updates to monitor the complete lifecycle from oracle query to final arbitration decision.

LA KROISETTE IN ACTION Optikle makes La Kroisette's revolutionary architecture tangible by showing users Reality.eth Oracle power for creating and answering questions with economic incentives, LayerZero v2 bridge magic for seamless cross-chain communication for arbitration requests, and Kleros arbitration excellence with professional dispute resolution by expert jurors.

THE VIBE-CODED DIFFERENCE Rather than showing the existing interfaces of Reality.eth and Kleros (i.e. https://reality.eth.limo and https://v2.kleros.builders), we vibe coded Optikle to embody the future of web3 UX with intuitive design language, seamless multi-chain flow where users never feel the complexity of cross-chain operations, unified oracle plus arbitration where both functions feel like natural parts of the same system, and real-time interactivity with live updates, smart notifications, and contextual guidance.

DEMONSTRATING THE VISION Through Optikle, La Kroisette proves that censorship-resistant, cross-chain dispute resolution isn't just a technical achievement - it's a practical, user-friendly reality. The interface shows how sophisticated blockchain infrastructure can be packaged into experiences that feel as natural as traditional web applications, while delivering the transparency, decentralization, and interoperability that makes web3 revolutionary. Optikle transforms La Kroisette from a technical demonstration into a living, breathing example of how decentralized applications can perform cross-chain while remaining accessible to everyday users.

Optikle can be seen at https://optikle.vercel.app (also to be seen in our video demo).

Core Architecture

• Dual-proxy design: Contracts on both Sepolia (Reality.eth) and Arbitrum Sepolia (Kleros)
• LayerZero V2: Handles cross-chain messaging with 5 custom message types
• Hardhat + Foundry: Dual development environment for maximum compatibility

Notable Technical Solutions

Sophisticated Message Routing: Implements 5 cross-chain message types with different gas limits and error handling patterns for the complete arbitration lifecycle.

Kleros V2: Provided production-ready arbitration infrastructure with dispute templates and evidence systems already integrated.

Oracle Question String Formatter: In order to properly render Reality.eth questions in a Kleros Dispute, since they're highly generic, they required custom handling. And because arbitrary JS is not allowed anymore, the data wrangling had to be done directly in Solidity.

We fought for a while to verify contracts in Arbitrum Sepolia, because Etherscan updated its API and none foundry or hardhat had any easy way of verifying contracts through the v2 API. 1h until we got our 1st verified contract

The NotEnoughNative revert in OAppSender.sol in Layer0 is super confusing. They assert msg.value == nativeFee for the message, but it reverts as if it was "not enough". This was especially bad because software is not supposed to be surprising (even though it was surprisingly "safe" and it will probable save money to users)