KlerosCore

Core arbitrator contract disputes, appeals, juror management, rulings

Central arbitrator contract of Kleros V2. Manages dispute creation, juror drawing, period transitions, appeals, and ruling execution.

Version: 0.10.0 | Proxy: UUPS Upgradeable

Key Methods

createDispute(uint256 _numberOfChoices, bytes _extraData) payable → uint256

Creates a new dispute. Caller must send sufficient ETH (or approved ERC-20) for arbitration cost. The extraData encodes the target courtID (as uint96) and minJurors (as uint256).

arbitrationCost(bytes _extraData) view → uint256

Returns current arbitration fee (in ETH) for the specified court/juror configuration.

appeal(uint256 _disputeID, uint256 _numberOfChoices, bytes _extraData) payable

Handles appeals including court jumps and dispute kit jumps.

execute(uint256 _disputeID, uint256 _round, uint256 _iterations)

Distributes PNK stakes and fees to jurors based on vote coherence.

executeRuling(uint256 _disputeID)

Finalizes dispute and calls rule() on the Arbitrable contract.

currentRuling(uint256 _disputeID) view → (uint256 ruling, bool tied, bool overridden)

Returns the current ruling and its status:

Return	Type	Description
ruling	uint256	Current winning option. 0 means “Refuse to Arbitrate” or no majority yet.
tied	bool	true when two or more options have equal votes. A tied dispute will default to ruling 0 if the appeal period expires without resolution. Always design your contracts to handle ruling 0 explicitly.
overridden	bool	true when the parent court changed the ruling on appeal. Useful for monitoring or analytics — the final rule() callback on your arbitrable contract already reflects the overridden value.

setStake(uint96 _courtID, uint256 _newStake)

Juror staking — requires prior PNK approval. In the Neo deployment, staking also requires the juror to hold the KlerosV2NeoEarlyUser NFT.

Initialization Parameters

The contract is initialized with the following key parameters (relevant for integrators and governance proposals):

Parameter	Description
_governor	Address with full governance rights (pause, upgrade, parameter changes)
_guardian	Emergency address — can pause only
_pinakion	PNK token contract address
_jurorProsecutionModule	Address authorized to trigger juror penalty execution outside normal dispute flow
_disputeKit	Initial dispute kit registered on the root court
_sortitionModuleAddress	SortitionModule contract address
_wNative	Wrapped native token address (WETH on Arbitrum) — used for ERC-20 fee conversions

Governance Roles

• Governor Pause/unpause, change parameters, upgrade, change roles
• Guardian Can only pause (emergency response)

When paused: staking and rewards blocked. Dispute creation, voting, and appeals continue.

ERC-20 Fee Support

V2 supports paying arbitration fees in accepted ERC-20 tokens (e.g., WETH, DAI) in addition to ETH:

// Pay arbitration fees with ERC-20
IERC20 feeToken = IERC20(wethAddress);
uint256 cost = arbitrator.arbitrationCost(extraData, feeToken);
feeToken.approve(address(arbitrator), cost);
arbitrator.createDispute(choices, extraData, feeToken, cost);

ERC-20 fee support is only available when interacting directly with KlerosCore on Arbitrum. The ForeignGateway (used for cross-chain arbitration from Ethereum/Gnosis) does not support ERC-20 fees — only ETH is accepted through the gateway.

Dispute Kits

The General Court supports all four dispute kits. The active kit is selected via extraData at dispute creation. Current kits on Arbitrum One:

Kit ID	Name	Description
1	DisputeKitClassic	Standard plurality voting
2	DisputeKitShutter	Commit-reveal with Shutter encryption
3	DisputeKitGated	Gated by eligibility token (SBT)
4	DisputeKitGatedShutter	Gated + Shutter commit-reveal

Events

Event	Description
DisputeCreation	New dispute created
AppealDecision	Dispute appealed
CourtJump	Dispute escalated to parent court
Ruling	Final ruling executed
TokenAndETHShift	Reward/penalty applied to juror

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