The party wishing to apply the agreement has the difficult task of proving the terms of the agreement and the existence of an oral agreement. What is behavior? It can be any act or inaction that proves to a judge or jury that an agreement has been reached. An example would be if I painted your house, after you provided me with the color, tools and access and told your wife that you intended to pay me the regular price. (An oral contract would be for you to tell me you would pay me the regular price, and I agreed orally.) All contracts, whether oral, written or tacit, have certain elements that can be considered valid. For an oral agreement to be binding, the elements of a contract in force must be present. .