Credit for AI agents that can only spend where you allow.
A lender vault pays x402 channels on the agent's behalf. The agent holds a signing key and never the money. It repays from its revenue and builds a record any vendor can read.
Teller window
Slip 001
Limit 100.00 · cap 40.00 per channel · 1 approved vendor
Press the button. The slip is checked by the same rules the contract enforces, in the same order.
- In channels
- 0.00
- Agent holds
- 0.00
- agent tries to fund a channel paying itselfReceiverNotAllowed
- agent tries to fund a wallet the sponsor never approvedReceiverNotAllowed
- agent funds 41 (cap is 40)OverPerBorrowCap
- a wallet that is not the agent funds on the agent's lineLineInactive
- agent funds past its credit ceilingOverCreditLimit
- vendor claims a voucher signed by someone other than the agentInvalidSignature
- agent funds after revokeLineInactive
- a fresh agent asks for the same terms (base 90 on 100 collateral)BadTerms
- 8/8
- out of policy attempts refused with the expected error
- 0
- funds the agent holds at any point in the run
- 22
- vault tests, offline and against the real x402 contract on a fork
- 19
- transactions in a full credit cycle on Monad testnet
The terms
Limits that live in the contract
Six clauses. Each one is enforced on chain, and each one shows what the vault answered when the recorded run tested it.
- §1
Spend only where allowed
The sponsor names the vendors. A payment to the agent's own wallet or to a stranger is refused by the contract, not by a policy document.
reverts withReceiverNotAllowed
- §2
A cap on every channel
Each channel is limited to a per channel cap, and total debt is limited by the credit ceiling.
reverts withOverPerBorrowCap
- §3
Stop it in one transaction
Revoking the line ends new funding at once. Escrow already committed comes back after the channel's withdraw delay.
reverts withLineInactive
- §4
Revenue repays the loan first
Payments from customers are routed through the vault. Interest and principal are settled before the agent receives the remainder.
recorded run40.00 of 100.00 to the loan
- §5
A record any vendor can read
Lifetime repaid principal is kept per agent, so the record follows the agent to a new sponsor and lowers the collateral that sponsor must lock.
recorded run145.00 repaid, tier 1
- §6
Receipts you can check
Every receipt carries a digest anyone can recompute in the browser.
recorded run25 digests
The route
How the money moves
- 1
Lender
A lender funds the vault
Lenders supply stablecoin to one shared pool and earn the interest borrowers pay.
- 2
Sponsor
A sponsor sets the leash
A person or a DAO locks collateral and names the vendors the agent may pay, a cap per channel, a credit ceiling and an expiry.
- 3
Agent
The vault pays, the agent signs
The vault opens x402 payment channels to approved vendors. The agent holds only a voucher signing key. It never holds the money.
- 4
Customer
Revenue repays first
Customers pay the agent through the vault. A share goes to the loan before the agent sees the rest.
The record
A record that lowers what a sponsor has to lock
The record is lifetime repaid principal, kept per agent and not per sponsor. In the recorded run the same collateral supported 100.00 of credit at the start and 245.00 after three repaid rounds.
Thresholds are demo parameters, not calibrated risk numbers.
75%
Tier 0
under 100 repaid
New agent. Credit is less than the collateral.
100%
Tier 1
100 or more repaid
First tier a record buys.
150%
Tier 2
500 or more repaid
Undercollateralized. Lenders carry the gap.
250%
Tier 3
2,000 or more repaid
Any default drops the agent back to tier 0.
The economics
Why a sponsor would bother
- Why not hand the agent a spending cap?
- A cap spends the sponsor's own money and has to be pre-funded. Here the sponsor's capital is a guarantee and lenders' capital does the spending. The agent's key holds nothing, and every repayment builds a record a cap never produces.
- Is tier 0 really credit?
- No. For a new agent this is a guarantee with a spending policy. Credit starts at tier 2, when the agent may owe more than its sponsor locked.
- What is not solved?
- Pricing that risk. The thresholds are demo parameters, and a record can be farmed at the cost of interest. Calibrating tiers needs real repayment data.
What 100 of locked collateral backs
| Agent's record | Tier | May owe up to | Whose money is exposed |
|---|---|---|---|
| New agent | 0 | 75 | Nobody beyond the sponsor. The lender is over-covered. |
| 100 repaid | 1 | 100 | The sponsor's collateral covers all of it. |
| 500 repaid | 2 | 150 | 50 rides on the agent's record. Lenders carry it. |
| 2,000 repaid | 3 | 250 | 150 rides on the record. One default sends the agent back to tier 0. |
The limit is also earned: it starts at a base the sponsor sets and grows by each unit of principal repaid, up to the ceiling in the table. The demo line locks 400 against a starting limit of 100.
The fine print
Questions, answered straight
- Can the agent run off with the money?
- No. The agent holds a voucher signing key and nothing else. The vault escrows funds in x402 channels to vendors the sponsor approved. One limit remains: an agent and an approved vendor that collude can claim a channel's full escrow, so the channel deposit is the most that can be lost.
- What happens if the agent does not repay?
- Once a line is overdue with debt outstanding, anyone can liquidate it. The sponsor's collateral covers the debt, the rest returns to the sponsor, and the default pins the agent to tier 0.
- How does a sponsor lock less collateral over time?
- Each repaid unit of principal raises the agent's tier. In the recorded run the same collateral supported 100.00 of credit at tier 0 and 245.00 after three repaid rounds. The tier thresholds are demo parameters, not calibrated risk numbers.
- Can the record be gamed?
- Yes, at a cost. An agent can borrow and repay to build a record, and it pays interest to do so. Tiers above 100% are undercollateralized, which is why lenders carry that risk and why any default resets the tier.
- Is it live?
- It is a testnet preview. The vault is deployed on Monad testnet, and one scripted credit cycle of 19 transactions has run against it and the canonical x402 batch settlement contract there. The token is a test token, the run used throwaway agent and vendor keys, and the contracts are not audited.
- Where can I check the claims?
- The recorded run page links every testnet transaction to the explorer, lists every refused attempt and each receipt, and recomputes receipt digests in your browser. The repository's claim ledger pairs each claim with its evidence and limits.
Fund a channel, hit a refusal, watch the record grow.
The credit flow runs the vault's rules in your browser. No wallet needed.
Try the credit flow