Documentation
How Plimsoll works.
Plimsoll is a savings vault for USDG on Robinhood Chain. You deposit USDG, it gets lent out to earn interest, and you keep 90% of what it earns.
The twist is the limit. You decide how much risk is too much, and nothing in the vault is allowed to go past it. The name comes from the Plimsoll line, the mark painted on a ship’s hull that shows how heavy it can safely be loaded.
The website works today. The rates and markets are examples, and deposits open once an outside firm has audited the code.
How it works
- You deposit USDG into the vault. USDG is a stablecoin, so one USDG is meant to be worth one dollar.
- You set your limits, or keep the defaults.
- Jev looks at the lending markets and decides how to split the money. Before anything moves, plain code checks that plan against your limits. If the plan breaks a limit, it gets thrown out.
- Borrowers pay interest on what they borrowed, and it flows back into the vault.
- We keep 10% of that interest. The other 90% is yours.
- You can withdraw whenever you want. The cash part comes out right away.
Your limits
On the vault page you can type your limits in normal words. These are the ones we understand right now.
| Limit | What it does | Words that work | Default |
|---|---|---|---|
| Risk level | How much risk the whole vault can carry | safest, balanced, more yield, max risk 0.15 | Balanced (0.11) |
| Max per market | The most that can go into any one market | max 35% in any market | 35% |
| Minimum market size | Skips markets that are too small | nothing under $20M | No minimum |
| Cash kept aside | How much stays as cash for fast withdrawals | keep 10% ready to withdraw | 5% |
| Minimum rate | Skips markets that pay less than this | only markets paying over 6% | None |
| Blocked markets | Never used, no matter what | no memecoins, no stocks, no ETH, no pools, no T-bills | Nothing blocked |
| Stablecoins only | Only stablecoin markets and T-bills | only stablecoins | Off |
If we can’t find any limits in what you typed, the Balanced defaults apply. The vault page always shows exactly what we picked up from your words, so you can check before anything happens.
The risk score
Every market gets a risk score between 0 and 1. It’s a rough measure of how much that market could swing. Tokenized T-bills sit around 0.05. Loans backed by memecoins sit at 0.55.
The vault’s score isn’t just the average. Markets don’t usually go bad all at the same time, so spreading money out brings the total down. We treat any two different markets as loosely connected, with a correlation of 0.3. For the curious, this is the math:
vault risk = √( Σᵢ Σⱼ wᵢ · wⱼ · rᵢ · rⱼ · cᵢⱼ ) w = share of the deposit in each market r = that market's risk score c = 1 for the same market, 0.3 for two different ones
The risk levels cap that number. Safest stops at 0.06, Balanced at 0.11 and More yield at 0.20. You can also set your own, anywhere up to 0.30.
How Jev decides
Jev is an AI model from TypeSafe AI. It’s built for making decisions inside software, not for chatting. You give it the situation, it picks between options and tells you how confident it is.
In Plimsoll, Jev’s job is to choose how to split deposits across markets. It never touches your limits. Those are checked by separate code, and any plan that breaks them gets rejected. If nothing fits, the money stays as cash.
Right now Jev runs the activity feed on the vault page. Every 20 seconds our server sends Jev the example markets and asks three things: which market should get the next 1% of the money, which market should give it up, and where the rate is likely to go over the next month. Jev answers each one with a pick and how sure it is.
Your browser then checks that pick against your own limits, the same way the vault contracts will. So two people with different limits can watch the same Jev answer and see one of them get a REBALANCE and the other a VETO.
The split you see on the vault page, under “Where $1,000 would go,” still comes from a simple calculator in your browser. It looks for the split that earns the most interest without going over any of your limits. Jev takes over that part once the contracts are ready.
The activity feed
Each line in the feed has a tag:
- TICK is a quick update on the current rate.
- REBALANCE means 1% moved from one market to another, with how sure Jev was.
- CHECK is the code confirming the move stayed inside your limits.
- VETO means Jev wanted a move and your limits blocked it.
- HOLD means Jev decided nothing should get more money right now.
- FORECAST is the outlook for the next 30 days.
- LIMITS shows up when your limits change or the feed connects to Jev.
The badge on the panel tells you which mode you’re looking at. Live means the decisions are Jev’s real answers. Simulated means our server couldn’t reach Jev, so the page is filling in with practice notes until it can. Either way, the markets and the money in the feed are examples. Nothing real moves until the vault opens.
Example markets
These six markets are examples that show how the vault works. The real list will be posted here before deposits open.
| Market | Rate a year | Deposited | Risk score |
|---|
Fees
There’s one fee. We keep 10% of the interest your deposit earns. Depositing and withdrawing cost nothing extra. You’ll still pay a small network fee in ETH for each transaction, like on any blockchain.
Say you deposit $1,000 and it earns $60 in a year. You keep $54 and we keep $6.
Withdrawals
You can ask for your money back at any time. The cash part of the vault pays out right away. If you ask for more than the cash on hand, the rest has to come back from the lending markets first, which can take a while when markets are busy. That’s the whole reason the cash limit exists.
Risks
A bug in the code
The vault is software, and software can have mistakes that lose money. Deposits only open after an outside firm audits it, and the first deposits will be capped low. An audit lowers the risk. It doesn’t remove it.
The collateral crashes
Borrowers back their loans with things like ETH or tokenized stocks. If those drop fast, a lending market can end up with bad loans and lose money. The size floor and the cap per market keep any single bad market from doing too much damage.
USDG loses its peg
USDG is supposed to always be worth $1. If it ever isn’t, everything in the vault is worth less. We can’t fix that one, so only put in money you can afford to have at risk.
Jev makes a bad call
The AI can pick a market that goes wrong later. It can only pick inside your limits, and plain code checks those before anything moves.
Everyone withdraws at once
Money that’s lent out takes a while to come back. During a rush, withdrawals bigger than the cash on hand may have to wait.
Contracts
Two contracts matter, and only one of them is ours to write.
| Contract | Who deploys it | Status |
|---|---|---|
| Vault Holds USDG, enforces your limits, pays withdrawals, takes the 10% fee. | Plimsoll, after the security audit | Being written |
| Token The Plimsoll token on Pons. | Pons, at launch | Coming soon |
The token and the vault are separate. Holding the token isn’t a deposit. Both addresses will only ever be posted on this page and in the bar at the top of the site.
Network details
Plimsoll runs on Robinhood Chain. If your wallet doesn’t have it yet, these are the settings to add.
| Network name | Robinhood Chain |
| Chain ID | 4663 |
| RPC URL | https://rpc.mainnet.chain.robinhood.com |
| Gas token | ETH |
| Block explorer | robinhoodchain.blockscout.com |
| Vault contract | Not deployed yet |
The vault’s contract address will be posted here after the audit. It’s a different address from the token’s (see Token). If anyone sends you a vault address before then, it isn’t ours.
Token
The Plimsoll token trades on Pons, the token launchpad on Robinhood Chain.
| Contract address (CA) | Coming soon |
| Network | Robinhood Chain (chain ID 4663) |
| Where to trade | Trade on Pons |
| Explorer | See it on BlockscoutAfter launch |
Copycat tokens with the same name are common. The only real contract address is the one on this page, so check it before you buy.
The token is separate from the vault. Buying it isn’t a deposit, and it doesn’t earn the vault’s interest. Like any token, its price can fall a lot, so only buy what you can afford to lose. Nothing here is financial advice.
Where things stand
- Website and calculatorLive
- Limits boxLive in your browser
- Wallet connectLive
- Vault smart contractsBeing written
- Jev in the activity feedChecking
- Jev moving real moneyAfter the audit
- Security auditNot started
- DepositsAfter the audit
- Token on PonsComing soon
Glossary
- USDG
- A stablecoin built to stay at $1.
- Robinhood Chain
- A blockchain built by Robinhood. It works with Ethereum wallets like MetaMask.
- Lending market
- A pool where some people lend coins and others borrow them, paying interest.
- Collateral
- What a borrower puts up to back a loan. If the loan goes bad, it can be sold to pay lenders back.
- Tokenized T-bills
- U.S. Treasury bills turned into tokens that live on a blockchain.
- Risk score
- Our rough number for how much a market, or the whole vault, could swing. Lower is calmer.
- Cash kept aside
- The part of the vault that isn’t lent out, so withdrawals can happen right away.
- Audit
- An outside security firm reading the code to look for mistakes before real money goes in.
- Wallet
- The app that holds your coins and lets you approve transactions, like MetaMask or Rabby.
FAQ
What’s Jev?
An AI model made by TypeSafe AI. It doesn’t write text like a chatbot. It picks between options and tells you how sure it is. We use it to decide where deposits go. We’re not part of TypeSafe AI, just a project that uses their model.
Can the AI ignore my limits?
No. Plain code checks your limits before any money moves, and the AI can’t change that code. If nothing fits, the money stays as cash.
Where does the interest come from?
From borrowers. They borrow USDG and put up other assets, like ETH or tokenized stocks, as a guarantee. The USDG / USDC pool also earns a small fee on trades.
How do you make money?
We keep 10% of the interest your deposit earns. Putting money in and taking it out is free.
Is the rate guaranteed?
No. Rates change every day. That’s why the calculator shows a low and a high scenario.
Can I lose money?
Yes. The risks section above lists how. Your limits make big losses less likely, but nothing makes them impossible.
Is there a token?
Yes, on Pons, the token launchpad on Robinhood Chain. The contract address is in the Token section. Always check it there before you buy. The token is separate from the vault: holding it isn’t a deposit and doesn’t earn the vault’s interest.
When can I deposit?
As soon as an outside security audit is done. Until then, the rates you see here are examples.