Protection for people whose AI agents trade for them. Underwriters back an AI trader with USDG on Robinhood Chain. If the market gaps past your loss limit, the agent stops and the bond pays you the rest. Our first claim has paid on testnet.
Bondline: when the market jumps past your AI trader's limit, the bond pays.
It already paid. In our demo market, a covered account's stock price jumped down over a weekend. The account fell from 92 to 75 USDG, a 25% loss, while the user's limit was 10%. A few seconds later the agent was stopped and the underwriter's bond paid the user 15 USDG. No claim form. See the transaction
Try it in 2 minutes, no wallet needed: the tour · Every claim with its proof: the judge kit · Code: GitHub
The problem
More than 150,000 Robinhood customers have opened accounts where AI agents trade for them, and Robinhood says the user carries all the risk of those trades. Rules can stop an agent from doing something reckless. They can't stop the market. When a stock jumps over a weekend or on news, a stop loss can't sell in time, and today the user eats that loss.
How Bondline works
The agent trades through an onchain account with fixed rules. The careful agent can't put more than 30% in stocks, the bold one 80%. Each trade it makes leaves a public receipt with the AI's reasoning.
The underwriter picks an agent, sets a price (the premium) and posts a bond in USDG, all with a single signature.
The user picks a loss limit, for example 10%. If the market pushes the account past it, anyone can trigger the payout: the agent stops, the user's loss stays at 10%, and the bond pays the rest, up to a 30% drop.
How to use it
Just looking: take the 2 minute tour. No wallet needed.
To buy cover: connect a wallet on Robinhood Chain testnet and tap "Get 5 test USDG". Then open Cover, pick an agent and your loss limit.
To underwrite: open Underwrite, pick an agent, set your bond and premium, and sign once.
Built for agents
Any AI agent can use Bondline, not just ours. Our MCP server and SDK let an agent list offers, get quotes, check an agent's track record and build unsigned transactions to buy cover, underwrite or trade. They hold no keys: the agent's own wallet signs. Agent docs
Why it's safe for both sides
The contract never sells more cover than the bond can pay, so every cover is fully backed before it's sold.
Riskier agents cost more. Our simple pricing model rates the careful agent at about 0.13% and the bold one at about 1.75%, 13 times more. Replaying real stock prices since June, the careful agent's covers would have paid 0 claims and the bold one's 17.
Bondline's contracts have no owner and can't be upgraded.
Why Robinhood Chain and USDG
Robinhood Chain is where tokenized stocks, AI trading and Paxos USDG come together. Every dollar in Bondline is USDG: the bond, the premium and the payout.
What's live on Robinhood Chain testnet
11 smart contracts, checked against the source code.
Two AI agents running on Claude, with public trading records.
Real underwriting offers, real covers and 1 claim paid.
A website with a 2 minute tour and a judge kit.
Quality and security
172 tests, 100% line coverage, formal proofs and mutation testing.
An independent review by AI agents that did not build Bondline. Every finding comes with a test that proves it. Result: no critical issues and one high issue (a payout can be delayed in a rare case), with a fix planned before mainnet. The full report is in the repo.
The pricing model is also written in Rust for Arbitrum Stylus and matches our main model on 16,071 test cases. Stylus deployments are paused on Robinhood Chain testnet right now, so it isn't deployed yet.
Business model
Underwriters earn the premiums and Bondline plans to take a small cut. Bondline itself never pays claims; the underwriters' bonds do.
Honest notes
Testnet only. This is a capped, fully backed protection bond, not regulated insurance. Not affiliated with Robinhood.
The claim above was a scripted price jump on our demo replay market, using our own test wallets. All underwriters and buyers so far are our test wallets.
A payout needs fresh prices and a working USDG transfer, so it can be delayed in rare cases. The user can always pause the agent or close the cover.
On testnet our keeper posts the prices, and a demo exchange fills trades at the oracle price.
What's next: get a professional audit, then launch a small capped beta on Robinhood Chain mainnet in USDG after legal review.