Tend — Robinhood Chain

Tend is a defined-risk BTC, ETH and MON trading terminal deployed on Robinhood Chain testnet. Traders choose UP or DOWN, an expiry and a fixed 1.5×, 2× or 3× total winning payout. Every signed quote specifies the premium, strike and maximum payout; the Solidity vault escrows the full obligation before opening the position. At expiry, only the final settlement price counts. A strictly favorable finish pays the chosen multiple; a tie or losing finish pays zero. Eligible positions can request a separate signed early-exit bid.

The product makes directional exposure understandable: the premium is the maximum trading loss, excluding gas, with no margin account or liquidation. The React app shows live Coinbase market data, model win probability, the exact strike and the payoff before purchase.

This is a testnet prototype. Collateral is valueless mock mUSDC. An admin posts the Coinbase expiry-minute reference to TendPriceOracle; the price is not independently attested on-chain. Contracts are unaudited and the app is not ready for real funds.

Tend began as an existing protocol. During this buildathon we deployed its Solidity factory and fully collateralized vault to Robinhood Chain testnet (chain 46630), launched a Robinhood-specific trading site and signer, added fixed 1.5×/2×/3× expiry payouts and signed early-exit bids, and integrated live Coinbase data. We replaced permissionless mock settlement with TendPriceOracle, which accepts write-once prices only from the admin, and seeded BTC/ETH/MON markets on Robinhood. The admin remains a trusted price source; this is not independent oracle verification. Public deployment addresses and build history are in the repository.