§ 24-3-1 [Parol Evidence Rule for Written Instruments]

When you sign a written contract or agreement, that document is treated as the final word on what both parties agreed to. You generally cannot go into court and say "but we also agreed to this other thing" if that other thing was never written down.

This rule stops people from using spoken conversations or informal promises made around the same time as the signing to change what the written contract says. If you want something to be part of the deal, it needs to be in the written document itself.

This protects everyone by making written contracts reliable and hard to change after the fact. If someone could always bring in verbal promises to override a written agreement, contracts would mean very little.