In general, as with any contract, in order to be valid, a prenuptial agreement must be in writing and signed by the parties. In most states, the parties must fully disclose all income and assets to the other party. In a few states, it may be possible to waive a full disclosure of income and assets, but the spouse waiving that right must do so knowingly. If it is difficult to determine the exact validity of all of the assets, for example in a small family-owned business, the agreement should acknowledge some type of approximate value.
Additionally, the terms of the agreement must be reasonable. An agreement cannot be unusually harsh and unfair or the court will likely decline to uphold it. Blatantly unfair agreements are termed unconscionable agreements. Usually this means no reasonable person would enter into agreement with such terms. If a court finds an agreement to be unconscionable, the agreement will not be enforced.
Finally, both parties must have a fair opportunity to review the proposed agreement and to have inde-pendent legal counsel. While an agreement where both parties did not hire counsel is not necessarily invalid, hiring attorneys is another step that can demonstrate to the court that the agreement is fairly drafted and that both parties are making informed decisions. This is particularly true if two attorneys negotiate the agreement drafting and redrafting various provisions to the satisfaction of the parties.