The documentation for the 0x API "quote" endpoint indicates that adding a
feeRecipientTradeSurplus parameter to the query should generate a transaction where any "trade surplus fees" get sent to that specified address, rather than the transaction-sender. The FAQ page further describes "trade surplus" (under the "Can I collect trade surplus (a.k.a. positive slippage)?" question) by saying "Trade surplus occurs when the user ends up receiving more tokens than their quoted amount".
I believe this means that when using the "quote" endpoint and whatever
buyAmount is specified, if the price has slipped favorably for the trader and they end up with slightly more of that token than literally the
buyAmount value, that is considered the "trade surplus".
However, in practice, when adding the
feeRecipientTradeSurplus parameter to a call to the "quote" endpoint, no change is seen in the returned
data calldata compared to not including that parameter, and when simulating the generated transaction, none of the extra
buyAmount is sent to the
feeRecipientTradeSurplus address. Example call:
The token this is being attempted against only has liquidity on Sushi; is there a limitation to that specific liquidity provider that isn't working for this parameter? Or am I using this parameter incorrectly?