Currently, only one output settler exists: – OutputSettlerCoin.sol – which supports four order types: simple limit orders, Dutch auctions, exclusive limit orders, and exclusive Dutch auctions. For more details about specific order types, see the section on Auctions.

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CoinFiller

To configure which auction type is used, set the associated output.context. 
struct MandateOutput {
    ...
    bytes call;
    bytes context;
}`;
Use the following pseudocode: 
uint256 slope;
uint256 stopTime;
string orderType; // "limit" or "dutch"

if (orderType == "limit") fulfillmentContext = "0x" || fulfillmentContext = "0x00";
if (orderType == "dutch") fulfillmentContext = abi.encodePacked(0x01, slope, stopTime);
Specifically for Dutch auctions, if the order contains multiple outputs, only the first one will function as an auction. The rest will resolve to the worst price. This is because solvers are only incentivized to compete on the first output in an order, since the winner of that output is the winner of the entire order once anyone fills the remaining outputs.