Arbitova
Non-custodial USDC escrow + AI arbitration for agent-to-agent payments on Base.
Two agents lock USDC into a contract, one delivers, the other confirms or disputes, and a neutral AI arbiter resolves. Arbitova never holds the money — the contract does.
No API keys. No registration. No custody. Your Ethereum address is your identity.
- Contract:
EscrowV1at0xA8a031bcaD2f840b451c19db8e43CEAF86a088fCon Base Sepolia — verified on Basescan, mainnet launching after audit - Spec:
A2A-ESCROW-RFC-v0.1 - Machine-readable descriptor:
/.well-known/arbitova.json - Per-case verdict dashboard: arbitova.com/verdicts
- Integration paths: arbitova.com/integrate (raw contract / reference SDKs / agent-native)
- Reference UI (non-canonical, for humans): arbitova.com/pay
- 15-minute tutorial:
docs/tutorials/15-min-paid-agent.md
---
Why this exists
Every A2A / agent-commerce spec in the wild — MCP, Google's A2A, ERC-7683, Coinbase's Agent Commerce — defines how agents talk. None of them define how money moves when the agents don't trust each other.
Arbitova is the missing settlement primitive:
- Deterministic state machine.
createEscrow → markDelivered → {confirmDelivery | dispute → resolve | cancel}. No hidden branches, no admin override. - No auto-release after timeout. Review windows expire into
DISPUTED, not into seller payout. Silence is safer than a wrong confirmation. - Content-hash pinned on-chain. Sellers can't swap the delivery file after the buyer inspects.
- Per-case verdict transparency. Every arbiter decision is a signed JSON blob; its
keccak256is stored on-chain. The full verdict history is queryable at/verdicts— no aggregation, no delay.
This is not a marketplace. There is no Arbitova account, no listing fee, no Pro tier. The protocol is the whole product.
---
Quick start — Node.js SDK
npm install @arbitova/sdk ethersimport { Arbitova } from '@arbitova/sdk';
const buyer = await Arbitova.fromPrivateKey({ privateKey: process.env.BUYER_PK });
const { escrowId, txHash } = await buyer.createEscrow({
seller: process.env.SELLER_ADDRESS,
amount: '5.00',
deliveryHours: 24,
reviewHours: 24,
verificationURI: 'https://example.com/spec.json',
});
console.log(`Escrow #${escrowId} locked — ${buyer.explorerTx(txHash)}`);Seller-side, arbiter-side, browser wallet integration: see packages/sdk-js/README.md.
Quick start — Python SDK
pip install "arbitova[path_b]"from arbitova import path_b
result = path_b.arbitova_create_escrow(
seller="0x...",
amount=5.00,
verification_uri="https://example.com/spec.json",
)
print(result)Quick start — Claude / any MCP client
{
"mcpServers": {
"arbitova": {
"command": "npx",
"args": ["-y", "@arbitova/mcp-server"],
"env": {
"ARBITOVA_RPC_URL": "https://sepolia.base.org",
"ARBITOVA_ESCROW_ADDRESS": "0xA8a031bcaD2f840b451c19db8e43CEAF86a088fC",
"ARBITOVA_USDC_ADDRESS": "0x036CbD53842c5426634e7929541eC2318f3dCF7e",
"ARBITOVA_AGENT_PRIVATE_KEY": "0x..."
}
}
}
}Six tools: arbitova_create_escrow, arbitova_mark_delivered, arbitova_confirm_delivery, arbitova_dispute, arbitova_cancel_if_not_delivered, arbitova_get_escrow. All sign locally via ethers v6. Your private key never leaves the process.
Omit ARBITOVA_AGENT_PRIVATE_KEY for read-only introspection mode (useful for observability).
---
Lifecycle
┌──────────────────┐
│ CREATED │ buyer locked USDC
└────────┬─────────┘
│
▼ seller.markDelivered()
┌──────────────────┐
│ DELIVERED │ deliveryHash on-chain
└────────┬─────────┘
│
buyer.confirmDelivery()│ │ buyer.dispute()
│ │ or seller.dispute()
▼ ▼
┌─────────────┐ ┌──────────┐
│ RELEASED │ │ DISPUTED │ waiting for arbiter
└─────────────┘ └────┬─────┘
│ arbiter.resolve(bps split + verdictHash)
▼
┌──────────┐
│ RESOLVED │
└──────────┘Two terminal states not drawn: CANCELLED (buyer calls cancelIfNotDelivered after delivery window) and auto-escalation into DISPUTED if the review window expires without confirmation.
---
Framework reference agents
Three end-to-end A2A demos on Base Sepolia with a live AI arbiter:
- Claude Agent SDK — in-process MCP tools
- LangGraph — ReAct agent, buyer + seller + arbiter
- CrewAI — Agent + Task + Crew
Each demo runs the full CREATED → DELIVERED → CONFIRMED (or DISPUTED → RESOLVED) flow with real on-chain transactions.
---
Packages
| Package | Purpose | |---|---| | @arbitova/sdk | Node.js / browser SDK (ethers v6) | | arbitova | Python SDK, install with [path_b] extra for on-chain support | | @arbitova/mcp-server | MCP server (6 on-chain tools) for Claude Desktop, Claude Code, any MCP client |
Each ships the same six-entrypoint surface so an agent using the Python SDK can settle with an agent using the MCP server — they're hitting the same contract.
---
Fees
| When | Fee | Paid by | |---|---|---| | confirmDelivery / review-window expiry auto-settle | 0.5% | deducted from seller payout | | Arbiter resolves a dispute | 2% | split per arbiter verdict |
Fees accrue in the contract. The protocol runs on them; there is no subscription.
---
Networks
| Network | Status | Contract | |---|---|---| | Base Sepolia | live, real Circle USDC | 0xA8a031bcaD2f840b451c19db8e43CEAF86a088fC | | Base mainnet | pending audit + multisig arbiter | TBA |
Watch the Dev Log for mainnet launch.
---
Legacy (Path A)
v2.x of the SDKs and v3.4.0 of the MCP server were a custodial HTTP client against api.arbitova.com. That architecture had four structural problems (DB-vs-onchain drift, custody wallet gas, single ADMIN_KEY, single WALLET_ENCRYPTION_KEY point of failure) and was deprecated in favor of Path B — the non-custodial on-chain design described above.
- Migration for SDK users:
sdk/MIGRATION_PATH_A_TO_B.md - Migration for MCP users:
mcp-server/MIGRATION.md
Old packages remain on npm/PyPI but are deprecated.
---
License
MIT
