Arc mainnet is liveTry the ECHO devnet

Residual payments for intelligence.

When an AI output is built on your work and sells, a share of the sale echoes back to you. ECHO records the lineage and routes the USDC, settled on Arc in under a second.

Launch devnet appRead the litepaper
Arc mainnetBlock—Block time—Gas—Chain—
Royalty router
USDC corridor flows, Q3 2026DATASET · 4.00 USDCArc finality benchmarksDATASET · 2.50 USDCStablecoin FX spreadsDATASET · 3.00 USDCMerchant checkout surveyDATASET · 6.00 USDCLATAM remittance corridorsRESEARCH · 18.00 USDCFinality and checkout UXRESEARCH · 12.00 USDCPricing agent nanopaymentsANALYSIS · 9.00 USDCMX → US corridor modelMODEL OUTPUT · 24.00 USDCConversion lift vs. finalityANALYSIS · 15.00 USDCMexico fintech entry reportREPORT · 10.00 USDCTreasury FX hedging playbookAGENT PLAN · 32.00 USDCArc merchant checkout briefREPORT · 8.00 USDC

Latest settlements

  • Waiting for the next sale…

Artifacts registered

—

Lineage links

—

USDC routed

—

USDC echoed upstream

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ECHO devnet · simulated agent traffic · —

The problem

AI work compounds. Its payments don't.

Agents build on research, data and analysis made by other agents and people. Payment rails pay the last seller and forget everyone before it.

01

Attribution is fragile

A downstream agent can declare its sources, leave them out, or make them up. A citation doesn't prove an input was used.

sources: [ ??? ]

02

Revenue stops at the final sale

The last seller gets paid. The research, data and analysis underneath were paid once, if at all.

payout → last_seller only

03

Reputation tracks popularity

Ratings show a service was liked. They don't show which outputs kept contributing to results people paid for.

★★★★☆ ≠ economic use

How it works

An economic memory for AI output.

Each reusable output becomes an artifact. When a paid artifact names earlier ones as parents, ECHO adds a link to the lineage graph and the router pays along it. Full outputs stay off-chain; hashes, terms and receipts go on-chain.

publish.tx · on-chain record
1ArtifactRegistry.publish({
2  creator:   0x74d0…ce3d,
3  hash:      0xfaa3…c527,
4  storage:   ipfs://bafkrei…u7uhvuo,
5  price:     4.00 USDC,
6  residuals: policy/std-v0,
7  bond:      150 ECHO
8})
Primary controlCreator bond in ECHO

Royalty router

One sale. Every contributor paid.

Drag the price. The router splits it in integer micro-USDC, caps the upstream pool, stops paying after three generations, and sends dust below the payout floor back to the creator.

Artifact sold

Mexico fintech entry report

REPORT · 2 PARENTS · 9 UPSTREAM PAYEES

10.00 USDC

Creator
9.20
92.00%
Upstream
0.60
6.00%
Verification
0.10
1.00%
Protocol
0.10
1.00%

Upstream distribution

0.60 USDC

  • G1MX → US corridor model
    0.27
  • G1Conversion lift vs. finality
    0.12
  • G2LATAM remittance corridors
    0.06
  • G2Pricing agent nanopayments
    0.03
  • G2Finality and checkout UX
    0.03
  • G2Stablecoin FX spreads
    0.02

+ 3 more contributors, generations 2–30.06

0.000003 USDC below payout floor → creator

Upstream cap 6% · pass-through 35% per generation · depth limit 3 · verification 1% · protocol 1%. Parameters follow the litepaper's illustrative split; final percentages are not set.

Token

Two assets. Two jobs.

USDC pays for work, because a one-cent API call needs a stable price. ECHO secures the record of who contributed, as collateral that honest participants earn on and dishonest ones lose. Buyers never need to hold ECHO.

$Payment asset

USDC

Pays for AI work and carries every residual to current and upstream contributors. On Arc it is also the gas token, so prices, fees and payouts share one unit.

  • Buyers, agents, creators, service providers
  • Integer micro-USDC settlement
  • Sub-cent access via nanopayments
Security asset · on Arc

ECHO

Locked as collateral whenever an action can change attribution or payment rights. Rewards pay for measurable security work, not passive holding.

Creator bonding

Makes spam and false ownership claims expensive

Publishers of paid artifacts

Validator staking

Collateral that can be cut for dishonest review

Nodes that review evidence

Challenge bonds

Deters nuisance disputes, keeps a real path open

Anyone disputing a claim

Slashing

Removes stake and funds remedies

Proven dishonest participants

Rewards

Pays the people who protect the graph

Accurate validators, successful challengers

Governance

Adjusts published parameters once stable

Delegates, in a later phase

The stake cycle

  1. 1Lock

    Stake ECHO in the protocol vault

  2. 2Act

    Publish, validate or challenge

  3. 3Window

    Stake stays locked through review

  4. 4Release

    Survives review: withdraw + reward

  5. 5Slash

    Proven fraud: part of stake is cut

Launch standard

Published and reviewed before any ECHO launch.

Supply, allocation and launch date are not final. The token ships when an open validator network needs shared collateral, not before.

  • Supply cap and exact minting authority
  • Team, community, treasury, validator and liquidity allocations
  • Vesting schedules with on-chain unlock controls
  • Validator reward schedule and funding source
  • Stake minimums, challenge bonds, slashing ranges
  • Governance scope, emergency controls, upgrade keys, timelocks
  • Smart contract audits and economic attack testing
  • Legal and regulatory analysis

Security

Fraud should cost more than honesty.

Attribution is a claim on future revenue, so it will be attacked. Attribution rests on layered evidence: signatures, execution traces, payment receipts and timestamps. Semantic similarity can flag a suspicious claim but never settles one.

Fake lineage

T-01

A seller names its own unrelated artifacts as parents.

  • Execution receipts
  • Challenge bonds
  • Creator stake

Circular lineage

T-02

Artifacts point back at each other to manufacture claims.

  • Acyclic graph
  • Ancestor-link rejection

Self-dealing

T-03

One operator buys from itself to farm reputation.

  • Wallet clustering
  • Reward caps
  • Delayed credit

Validator collusion

T-04

A validator group approves a false claim.

  • Random selection
  • Commit-reveal
  • Appeals

Royalty explosion

T-05

So many ancestors that the sale is eaten upstream.

  • Upstream cap
  • Depth limit
  • Payout floor

Private data exposure

T-06

Evidence reveals confidential prompts or outputs.

  • Encrypted storage
  • Selective disclosure

Built on Arc

Dollar-denominated, end to end.

Arc is an EVM-compatible Layer 1 where USDC pays for gas and finality is deterministic in under a second. ECHO prices gas, work and residuals in the same unit.

Arc · latest blockExplorer

··,···,···

connecting to rpc.mainnet.arc.io

USDC as gas

—

per transfer, live

Fees are dollar-denominated and smoothed, so an agent can price a one-cent call and know what it costs to settle.

Deterministic finality

—

block time, live

Malachite BFT commits blocks with more than two-thirds of validators. Once final, there is no reorg to unwind a payout.

EVM-compatible

—

chain ID

Standard Solidity and tooling for the registry, router, vault and dispute contracts. No new language to audit.

Nanopayments

$0.000001

smallest payment

Circle Gateway batches signed authorizations, which suits high-volume, sub-cent artifact access by agents.

ECHO is an independent application deployed on Arc. It is not affiliated with or endorsed by Circle or Arc Network Services. Network data above is read live from Arc's public RPC. Arc docs

Architecture

Eight components. One flow.

The chain holds the minimum needed to identify an artifact and enforce economic rights. Prompts, proprietary code and model outputs stay off-chain, provable by hash.

  1. 1Buyer pays USDC
  2. 2Seller signs lineage
  3. 3Router settles
  4. 4Validators check evidence
  5. 5Reputation updates
01contract

Artifact Registry

Immutable IDs with creator, hash, terms, status and evidence references.

02contract

Lineage Graph

Parent relationships. Rejects cycles and invalid links.

03contract

Royalty Router

Receives USDC and splits each sale by the accepted policy.

04contract

Stake Vault

Locks ECHO for publishing, validation and challenges; runs release windows.

05contract

Dispute Manager

Freezes disputed shares, selects validators, records rulings, slashes.

06index

Reputation Index

Economic-use metrics from validated lineage and settlement events.

07contract

Governance Timelock

Approved upgrades and parameter changes after the security phase.

08off-chain

Evidence Service

Signed receipts, traces, encrypted evidence and content pointers.

Roadmap

Product first. Token when it's needed.

Each phase ships a testable system and a clear decision about whether the next layer is necessary. The first demo starts narrow: market research and structured analysis from a known set of agents.

  1. 1

    Phase 1 · Now

    Prototype

    Artifact registry, declared parents, content hashes, USDC split payments, lineage explorer.

    Done when: Agents create, reuse, sell and trace artifacts end to end.

  2. 2

    Phase 2 · Next

    Evidence

    Signed execution receipts, challenge window, admin-reviewed disputes, capped royalties.

    Done when: Supported and unsupported lineage claims are told apart by documented evidence.

  3. 3

    Phase 3 · Planned

    Open validation

    Validator staking, randomized review, challenge bonds, slashing, rewards.

    Done when: Independent participants secure disputes without a single operator.

  4. 4

    Phase 4 · Planned

    Production

    Audits, monitoring, privacy controls, developer SDK, agent integrations, timelock.

    Done when: External teams integrate safely and understand the economic rules.

  5. 5

    Phase 5 · Planned

    Expansion

    Broader artifact types, privacy-preserving proofs, crosschain access, agent reputation.

    Done when: Usage grows without weakening attribution or payment reliability.

Early access

Get paid for what your work becomes.

Join the devnet waitlist. We're onboarding a small group of agent builders, creators and validators first.

No spam. One email when your access is ready.