Limits it can't argue with
Position size, leverage, daily loss, a market allowlist, and a cap on what one trade may lose if its stop fills. There is no tool that changes them, so no prompt or clever reasoning gets past them.
Let an AI agent trade without giving it the power to lose everything.
Reins sits between your agent and Hyperliquid. Position size, leverage, daily loss, which markets it may touch and a stop on every position are enforced outside the model, and every decision is written down with the reason the agent gave for it.
$ npx @r2rlabs/reins init
terminal
$ npx @r2rlabs/reins init
✓ Paper mode — live prices, simulated fills, no capital at risk
✓ Limits — max position $5,000 · daily loss $500 · $100 risk per trade · BTC, ETH
✓ Decision log — ./decisions.jsonl
✓ Builder fee — 2 bp to Reins on live orders; paper results include it
→ 9 tools on stdio. Point your agent at it.
What it does
Rehearse on real prices
Paper trading on live Hyperliquid prices with realistic fills and fees, using the same tools and the same limits as live. Nothing is signed, and no key is needed.
Every decision on the record
Each order, refusal, wait and stop-out is stored with the reason given for it. When something strange happens at 3am, you can read exactly what it thought it was doing.
Any bot can plug in
Agents speak to Reins over MCP. Everything else speaks HTTP: swap “send this order to the exchange” for “send it to Reins”, and inherit the limits and the log without changing anything else.
$ npx @r2rlabs/reins http --port 8787 $ curl -H "Authorization: Bearer $TOKEN" \ -d '{"symbol":"ETH","side":"buy","sizeUsd":1000,"stopLoss":2620,"reason":"Breakout retest"}' \ http://127.0.0.1:8787/orders 400 BLOCKED (TRADE_RISK_TOO_LARGE): Stopping out would lose $50.99, over the $30 allowed on one trade. Move the stop closer or send a smaller order.
Routes for limits, positions, book, candles, orders, stops, cancels, closes and the log itself. It binds to your own machine and needs a token; a refused order comes back with the limit that stopped it.
Most Hyperliquid bots are Python, so there is a client rather than a snippet — pip install reins-client, no dependencies. A refused order raises Refused carrying the code, and size_for_risk() is the same arithmetic the engine checks, so an order can be sized into the per-trade limit instead of being refused by it.
What the record is for
An agent's explanation of its own trading is testimony, not fact. Reins stores the reason and the outcome side by side, so the two can be compared.
In a five-day paper run, the log caught the agent misreporting its own trade twice. Once it wrote that it was exiting at 81,021 “rather than wait for the 81,060 stop”. It filled at 81,063, worse than the stop it meant to beat.
| $17.08 | Worst single trade, 0.17% of the account |
| 0 | Positions left without a stop, and 0 orders that breached a limit |
| 7 of 10 | Trades closed by a stop the exchange held, several while the agent slept |
| 141 | Records written, including the 72 times it decided not to trade |
What Reins is, and is not
What it is
- Limits outside the model. Checked before anything reaches the exchange.
- A record you can check. Refusals and waits included.
- Somewhere to rehearse. Paper trading on live prices, free.
- Non-custodial. It trades through an API wallet that cannot withdraw.
- Paid for openly. A 2 bp builder fee on live orders, shown up front.
What it is not
- Not a trading bot or a strategy. It doesn't decide what to trade.
- Not an exchange, broker or custodian. Hyperliquid matches the orders.
- Not a promise against losses. Limits cap what can go wrong, not the market.
- Not financial advice.
- Not something you take on trust. Every action is on the record.
- Limits live outside the model.
- The record outranks the reasoning.
- Paper before real money.
- Your keys, your funds.
Start on paper
Paper trading costs nothing and needs no key. Point Claude, Cursor, or your own bot at it and watch what it does.
$ npx @r2rlabs/reins init