How Euthyna works

Euthyna is an AI treasurer for small businesses. It pays your bills in USDC, keeps enough cash on hand for what's coming due, and parks the rest in a reserve.

Most AI agents get a spending limit from a config file, which means trusting whoever wrote it. Euthyna's limit lives in a smart contract and moves only with the agent's own track record, which the contract checks itself. It's an AI treasurer on probation.

1. 01
   You own a vault

   A smart contract that holds your USDC, your approved payees and your bills. Your wallet is the owner. The agent has its own Circle wallet and can act only through the vault.
2. 02
   The agent pays bills

   Before each bill is due, the agent pays it, but only to payees you approved and only within limits the contract enforces. It has no function that sends money to an address of its choosing.
3. 03
   It makes commitments

   When cash sits idle, the agent moves some into reserve and commits on-chain: “every bill due before time T will still be paid on time from liquid cash.”
4. 04
   The contract grades it

   After T (plus a short grace period), anyone can call settle(). The contract checks its own records: if every covered bill was paid on time, it's a hit; otherwise, a miss.
5. 05
   The limit moves

   A hit raises the agent's score, and with it the amount it can pay on its own. A miss halves the score and freezes sweeps for 24 hours.

[ Before you start ]

1. a.Install MetaMask.
2. b.Get free test USDC from faucet.circle.com. Choose Arc Testnet and paste your address. On Arc, USDC is also the gas token.
3. c.Pick one real bill (hosting, a subscription, a supplier) and get the payee's wallet address. Keep it at 25 USDC or less so the agent can pay it on its own.

[ Set up: 3 signatures ]

1. 01
   Create your vault

   Open Onboard and connect your wallet; Arc Testnet is added automatically. Optionally enter a business name (shown publicly), then click Create. You get your own vault and agent wallet.
2. 02
   Add a payee

   Paste the payee's address and a name. Keep or lower the default limits. The page then shows when the payee goes live, about 1 hour later.
3. 03
   Register the bill

   Enter the amount and an invoice number. The due date defaults to 1 hour after go-live, and earlier dates are refused, because the agent couldn't pay them in time.
4. 04
   Fund the vault

   Send test USDC to your vault address, from the faucet or from MetaMask. Send enough to cover the bill, plus a little extra.

[ What happens next ]

The agent checks your vault every 30 minutes and whenever a new bill arrives, and pays the bill before it's due. Your business shows up in Live businesses on the home page.

Connect your wallet and the console opens your vault automatically. Any vault can be viewed with ?vault=0x… in the URL.

• +Allowlist only. The agent can pay only payees you added, and only bills that exist.
• +Payee delay. A new payee goes live after a delay (1 hour on production vaults, never under 10 minutes), so nobody can add an address and get paid instantly.
• +Per-payee caps. Each payee has a max per invoice and a max per month.
• +Limits in the contract. Bills above the agent's limit or daily cap are escalated to you, not paid.
• +A cash floor. The agent can't sweep cash below the vault's minimum liquid balance.
• +The model never decides a number. Code computes every amount; the policy layer rejects or clamps anything outside the rules, and the contract has the final word.

Euthyna ships an MCP server, so you can ask Claude, Cursor or any Model Context Protocol client about a vault in plain English: its cash, the agent's decisions, its trust record. It can also verify any decision's hash for you. It is read-only and holds no keys, so it can't move money.

[ Set up (Claude Code) ]

git clone https://github.com/theyuvan/Euthyna
cd Euthyna/mcp && npm install
claude mcp add euthyna -- node "$(pwd)/dist/index.js"

Claude Desktop, Cursor and HTTP setup are in the MCP guide.

[ Then ask ]

• +“What's the state of the Euthyna production vault?”
• +“What did the agent decide in its last 5 runs, and why?”
• +“Has the agent kept its promises? Show its trust history.”
• +“Verify the agent's last decision that moved money.”

Deeper docs live in the repository:

• +contract.md: mechanism, scoring, the 22-attack loophole audit, deployed addresses
• +backend.md: the agent loop, LLM chain, setup, full API reference
• +frontend.md: pages, wallets, running and deploying the console
• +mcp/README.md: the MCP server, its tools and client setup