Training and role
A class still in development
The proposed role concerns disputes between people and institutions: preparing an agreement, finding terms both sides will accept and deciding when an agreement cannot be kept. These are intentions for the class, rather than services a player can use today.
There is no playable Diplomat ability set to describe. The other class pages and the wiki list the available alternatives.
Negotiation remains possible through ordinary roleplay. A character does not need this unfinished class to bargain, mediate or take an interest in a city's affairs.