Pricing: the BBO read

The read

(bid, ask) = staticcall(0x…080e, abi.encode(assetIndex))
mid = (bid + ask) / 2            // integer, on the tick grid
price1e18 = mid × 10^(12 + szDecimals)

The read reverts if either side is zero or the book is crossed, so no trade can price off an empty book.

What this gives up, and what it gives

Only markets with a Hyperliquid book can be listed. In return there is no off-chain component to trust: the BBO is HyperCore state, read in the same block as the trade.

Toro's guards

The target accepts any uncrossed book. Toro also checks each read against per-market limits, set from measured book data (Price guards):

Freezing and retiring a market

The guardian can halt new opens everywhere, or freeze or retire one market. A frozen or retired market records its last mid; open positions close and liquidate at that frozen price. Retirement is permanent; a relisting uses a new market id.