S rest 213
NOTE: this decides what the TERMS of a K are. The rules of K interpretation then decide what those terms mean (and that usually means it is interpreted in light of extrinsic circumstances like trade usage and course of dealing)!.
1. is the K an integrated agreement?
2. If the K is completely integrated, then no additional terms are provided by oral agreements.
If, however, an agreement is only partially integrated, orally agreements can still provide consistent additional terms if
1) the oral agreement was agreed to for separate consideration, or
2) it is such a term as in the circumstances might naturally be omitted from the writing.
when applicable the rule renders unenforceable oral agreements entered into prior to the adoption of a written contract.
Rationale: the formal writing reflects the parties' minds at the point of maximum resolution, hence the provisions that do not appear in the document were not intended to survive; protects from outright fraud.