inference, onchain_
1 CREDIT = $1 of AI.

// CREDIT uses 6 decimals. 20e6 = $20 of AI, paid in ETH at Chainlink's price.
(uint256 total,,,) = sale.quote(20e6, address(this));
sale.buyAndActivate{value: total}(20e6, wallet, address(0)); // API balance for wallet

// or take resold CREDIT when the book is cheaper
(uint256 filled, uint256 cost, uint256 fee) = book.quote(20e6);
if (filled == 20e6 && cost + fee < total) {
    book.buyAndActivate{value: cost + fee}(20e6, wallet, address(0));
}