The conditions and terms of a deal are binding for the rest of the current player’s turn. No player may go back on their word in that time.
However, any offer or promise that extends to the next turn or later may be ignored or reneged without penalty — unless an Obligator or High Prelan card is played.
The Final Empire has a solution for duplicitous deal-makers. These two Personality cards make any deal binding until all offers, promises, and other terms are fulfilled.
Anyone may play an Obligator or High Prelan, even a player who isn’t involved in the deal. Uninvolved players may find it helpful to ensure certain deals persist, especially when they stand to benefit from them.
It’s a legitimate tactic to promise you’ll do something during a later turn, only to renege when the time comes. Alternately, you may make a promise you simply can’t keep later (e.g. vowing to dedicate a resource to a Problem the next Active Player will negotiate, only to have that resource removed from your supply beforehand)
With an Obligator or High Prelan in play, you could be required to do something beyond your power. In this case the player controlling the Personality returns 1 of your resources to the supply. When a High Prelan is Allied, 2 resources are returned instead. You may only lose resources you currently possess.