I think the OP means "trades" as in diplomatic bartering for techs/planets/open borders and stuff, not "trade routes".  He wants Lord Kona to list prices for everything, like a shopkeeper in an RPG, so that we can shave the margins closer without tedious trial-and-error.

Actually, that sounds like a legitimate function of a society's diplomatic corps: knowing, or guesstimating, what values an alien culture places on various commodities.  They should brief you with their own estimate of race X's bartering metric.  At low levels of tech / expertise / clout / sensors, they could be way off.  As you gain mastery or omniscience, you converge to race X's true function (and they converge to yours).  Model it as an error function that starts high and decreases with skill.  It could be the diplomatic equivalent of the sensors-vs-stealth arms race

On the flip side, there could be a cost for each barter offer that fails, representing AI's annoyance / loss of patience.  If alien leader deems you a spammer, you might lose trading privs for several UP cycles ...