---
title: "Kleros (PNK)"
url: "https://caper.network/wiki/daos/infrastructure/kleros"
updated: 2026-09-08
license: CC-BY-4.0
license_url: "https://creativecommons.org/licenses/by/4.0/"
---

# Kleros (PNK)

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| **What it is** | A [decentralized arbitration protocol](https://docs.kleros.io/court/overview): a blockchain "court" that resolves subjective disputes smart contracts cannot, by drawing anonymous jurors and paying them to reach a [Schelling point](/wiki/economics/schelling-points) on the honest answer. |
| **Token** | PNK (pinakion) — jurors stake it to be drawn; holders govern the protocol. Total supply [915,528,222 PNK](https://docs.kleros.io/concepts/pnk-token), changeable only by DAO vote. |
| **Governance** | PNK holders → Kleros Improvement Proposals (KIPs) → [Snapshot](https://snapshot.org/#/kleros.eth) vote → the [Governor contract](https://blog.kleros.io/governor-explainer/) auto-enforces the change on-chain. |
| **Founded** | 2017 (Coopérative Kleros, France) by [Federico Ast and Clément Lesaege](https://medium.com/kleros/kleros-a-decentralized-justice-protocol-for-the-internet-38d596a6300d); court live 2018. |
| **Deployments** | **Court V1** — Ethereum L1 (live since 2018, 1,500+ disputes resolved) and Gnosis Chain. **Court V2** — [Arbitrum L2, in beta](https://docs.kleros.io/court/overview) with 100+ disputes processed. |
| **Archetype** | Dispute-resolution-as-a-DAO. Distinct from [UMA](/wiki/daos/infrastructure/uma)'s optimistic oracle: Kleros is a standing _court_ whose security is a staked-juror Schelling game, not an assert-and-dispute bond. |

**Kleros** is a decentralized [arbitration protocol](https://docs.kleros.io/court/overview) — a "court" that resolves the subjective disputes smart contracts cannot decide on their own: was a freelance deliverable actually delivered, is a token listing legitimate, did an insured event really occur. Its name and design borrow from the Athenian [kleroterion](/wiki/economics/schelling-points), the stone machine that selected citizen jurors by lot. Where a price-feed oracle like [Chainlink](https://chain.link/) reports objective data, Kleros adjudicates _judgment calls_ — and it does so as a DAO, where the same token that pays jurors also governs the protocol.

## The court: stake PNK, get drawn by lot

Anyone can become a juror by staking [PNK (pinakion)](https://docs.kleros.io/concepts/pnk-token) in a court. When a dispute arrives, the protocol draws jurors at random from the staked pool, **weighted by stake**: the more PNK you stake, the higher your probability of being drawn for any given case (buying a controlling share of the vote therefore costs progressively more as PNK grows scarce). Drawn jurors review the evidence submitted by both parties and vote on the ruling — typically _Yes_, _No_, or [Refuse to Arbitrate](https://docs.kleros.io/court/overview) — often through a commit-and-reveal scheme that hides each vote until all are cast, so jurors cannot simply copy one another. Where the PNK sits differs by version: in V1 it never leaves the juror's wallet and is simply locked against the subcourt, while [V2 transfers it to the contract](https://docs.kleros.io/court/overview).

## Coherence: making honesty the focal point

Kleros never tells a juror what is "true." Instead it pays jurors to converge on what they expect _other honest jurors_ to pick — a [Schelling-point](https://kleros.io/static/whitepaper.pdf) game drawn straight from [coordination theory](/wiki/economics/schelling-points). After a ruling, jurors who voted **coherently** (with the majority) collect the [arbitration fees](https://docs.kleros.io/concepts/tokenomics) plus PNK redistributed from the jurors who voted **incoherently**; incoherent jurors forfeit a portion of their staked PNK. A juror who votes randomly, or is bribed to vote against the evident truth, is more likely to land in the minority and lose money — so the profit-maximising move is to read the evidence and vote the honest answer. This is the same "vote for what you think others will honestly vote" logic that secures [UMA](/wiki/daos/infrastructure/uma)'s DVM, implemented as a persistent, subcourt-structured jury rather than a single dispute round.

## The court tree and appeals

Courts form a [tree](https://docs.kleros.io/court/overview): a **General Court** at the root, with specialized **subcourts** beneath it (e.g. curated-list, oracle, or commerce disputes), each with its own parameters, stake requirements, and juror pool. A dispute can be **appealed**: each appeal round draws a larger jury — roughly twice the previous size plus one — and both sides (or third-party [crowdfunders](https://docs.kleros.io/court/appeals), who are rewarded if their side wins) must fund the higher juror fees. Because winning an appeal requires corrupting an ever-larger, freshly-drawn jury, the cost of buying a wrong outcome rises with each round, while an honest litigant can always escalate. If the protocol itself were ever 51%-attacked, PNK's [final backstop](https://docs.kleros.io/concepts/pnk-token) is a governance fork that removes the attacker's stake — a recourse an external token could not provide.

## Court V2: the same game, rebuilt modular on Arbitrum

Kleros has been running two courts in parallel since 2024. **Court V1** is the production protocol described above: a single monolithic contract, `KlerosLiquid`, deployed on Ethereum L1 and Gnosis Chain, which has resolved [more than 1,500 disputes](https://docs.kleros.io/court/overview) since 2018. **Court V2** runs on **Arbitrum L2** and, in Kleros's own words, “keeps the same crypto-economic model as V1 and changes how it is implemented and where it runs.” The monolith is split into `KlerosCore` (dispute coordination), a separate `SortitionModule` (juror drawing), and pluggable **DisputeKits** that supply the resolution mechanism itself.

Three of those changes matter to anyone reasoning about the design rather than the code. First, **the vote-hiding scheme became a choice**: V1 has one mechanism (commit-reveal with plurality aggregation), while V2 ships _Classic_, _Shutter_ (threshold-encrypted rather than commit-reveal), _Gated_ (eligibility gated by a soulbound token) and _GatedShutter_ — so a subcourt can pick how secret and how permissioned its jury is. Second, **cross-chain disputes are relayed rather than redeployed**: V1 meant separate, unconnected deployments per chain, while V2 routes disputes from any EVM chain to the Arbitrum court over the **VEA bridge**. Third, **staking custody moved** — PNK is transferred into the contract instead of being locked in the juror's own wallet. Running the court on an L2 is the point: the drawing, voting and appeal rounds described above are gas-heavy, and they were priced out of small disputes on L1.

V2 is [still in beta](https://docs.kleros.io/court/overview) — 100+ disputes processed, with internal review and external audits ongoing — and V1 remains live and paying staking rewards, so the two are not a migration so much as an overlap. (Checked 8 September 2026.)

## PNK as a governance token, and the wider stack

PNK's second job is governance. Holders propose [Kleros Improvement Proposals (KIPs)](https://forum.kleros.io/t/kip-69-parameter-updates-april-2024/1086), debate them on the [forum](https://forum.kleros.io/), and vote via [Snapshot](https://snapshot.org/#/kleros.eth); approved parameter changes are executed on-chain by the [Governor contract](https://blog.kleros.io/governor-explainer/), so the DAO can add courts, retune stakes and fees, or alter the very token supply. On top of the court sit Kleros's products — [Escrow](https://docs.kleros.io/products/escrow) (arbitrated P2P payments), [Curate](https://docs.kleros.io/products/curate) (token-curated registries whose entries are policed by the court), [Proof of Humanity](https://proofofhumanity.id/) (a sybil-resistant registry of real people), and a general-purpose [arbitrable-transaction oracle](https://docs.kleros.io/developers/overview) that any dApp or DAO can plug into for a credibly-neutral verdict.

## How Caper approaches this

Kleros exists because collectives constantly face questions that no vote can settle honestly on its own — "did this actually happen?", "is this claim legitimate?" — and someone must adjudicate them without a trusted middleman. [Caper](/wiki/foundations/what-is-a-caper) does not run a court, and it would be dishonest to pretend it arbitrates disputes. Its answer to the deeper problem Kleros targets — _what do you do when the group reaches a decision you consider illegitimate?_ — is not adjudication but [exit](https://caper.network/blog/the-exit-right). A caper member who believes the DAO is being run against their interests can redeem their proportional slice of the treasury and leave, because a member's [vote weight](/wiki/governance/voting-mechanisms) is the _same_ canonical share that governs their [exit](/wiki/foundations/what-is-a-caper) payout. Kleros makes defection costly by paying jurors to converge on the truth; Caper makes capture costly by guaranteeing that anyone outvoted can always walk away with their fair share intact. Both are Schelling-point designs — one coordinates jurors on an honest verdict, the other coordinates members on a proportional, non-dilutable claim.

## References

- Clément Lesaege, Federico Ast & William George, [Kleros Short Paper](https://kleros.io/static/whitepaper.pdf) — the Schelling-point juror model, appeals, and coherence incentives.
- Clément Lesaege, William George & Federico Ast, [Kleros Long Paper (Yellow Paper)](https://kleros.io/static/yellowpaper.pdf) — full cryptoeconomic specification.
- Kleros docs, [PNK Token](https://docs.kleros.io/concepts/pnk-token) — 915,528,222 total supply, matching the mainnet contract's on-chain `totalSupply` (the 764,626,704 figure still printed on the docs' [Tokenomics](https://docs.kleros.io/concepts/tokenomics) page is stale); juror-staking and governance roles, 51%-attack resistance.
- Kleros docs, [Court](https://docs.kleros.io/court/overview) — drawing, evidence, Yes/No/Refuse-to-Arbitrate voting, and the court tree.
- Kleros docs, [Appeals](https://docs.kleros.io/court/appeals) — appeal-fee crowdfunding and the asymmetric 2× / 1× funding rule that decides an unanswered appeal by default.
- Kleros blog, [Governor Explainer](https://blog.kleros.io/governor-explainer/); [KIP-69 Parameter Updates (Apr 2024)](https://forum.kleros.io/t/kip-69-parameter-updates-april-2024/1086) — on-chain governance via KIPs and Snapshot.
- Kleros docs, [Court — Overview](https://docs.kleros.io/court/overview) — the V1/V2 comparison table, the DisputeKit list, the VEA bridge, and the beta status of Court V2 on Arbitrum.