Module 2: Terms & Interpretation

When a written agreement is integrated — meant as the final, complete expression of the deal — the parol evidence rule generally bars evidence of prior or contemporaneous statements offered to contradict or add to its terms. A merger (or integration) clause, stating the writing is the complete agreement, is strong evidence of integration.

This rule is narrower than it sounds, though: it doesn’t bar evidence offered to resolve a genuine ambiguity in a term, or to prove fraud, mistake, or that a condition to the contract’s very existence was never satisfied. Those are recognized exceptions, not loopholes.

Masterson v. Sine refined how courts actually decide whether a writing was meant to be complete. A brother and sister-in-law sold a ranch to Sine but reserved an option to buy it back, and the writing said nothing about whether that option could be assigned to someone outside the family. Justice Traynor allowed outside evidence on that point, reasoning courts should ask whether the parties would naturally and normally have included this particular term in the writing if they’d actually agreed to it — a family-only limitation on an option is exactly the kind of detail people often leave to an informal side-understanding rather than the formal deed itself, even in an otherwise complete writing.

Example. Peter and John sign a written contract for John to landscape Peter’s yard for $2,000, with a merger clause stating the writing is their “entire agreement.” Peter later claims John also verbally promised, before they signed, to trim the trees for free. Because the writing is integrated, Peter generally can’t use that prior verbal promise to add a free tree-trimming term — the merger clause signals the parties meant the signed document to be the whole deal. But if Peter instead wanted to show that “the yard” in the contract was genuinely ambiguous between the front yard and the full property, that evidence would still come in, because resolving a real ambiguity isn’t the same as contradicting or adding a term.

When a term is genuinely ambiguous, courts don’t just guess. Under contra proferentem, ambiguity is generally construed against whichever party drafted the term. The UCC also recognizes a hierarchy of evidence for resolving ambiguity: express terms first, then course of performance (how the parties have acted under this very contract), then course of dealing (their pattern in prior contracts with each other), then usage of trade(industry-wide custom).

Frigaliment Importing Co. v. B.N.S. International Sales Corp. — the famous “what is chicken?” case — shows this hierarchy actually working through a genuine dispute. A buyer wanted young broiling chickens; the seller shipped older stewing chickens, both fitting the literal word “chicken” in the contract. Judge Friendly worked through the available evidence in roughly this order — the contract’s own language, then trade usage (conflicting expert testimony on what the poultry industry meant by the term), then a federal regulation defining “chicken” broadly — and, unable to find the buyer had proven its narrower reading was the one actually agreed to, ruled for the seller. The case is as often cited for showing how genuinely hard interpretation can get as for its result.

Example. Peter’s contract with John, a supplier, calls for delivery of goods in “cartons.” Peter drafted the contract and assumed a carton meant 12 units; John assumed 24, matching how every other supplier in their industry packs cartons. Because Peter drafted the ambiguous term, contra proferentem would tend to favor John’s reading against Peter. And separately, since Peter and John have no prior history together to draw a course of dealing from, the industry-wide practice — usage of trade — supports reading “carton” as 24 units.

Parties rarely address every possible issue, so courts and the UCC supply default answers for genuine gaps — this is gap-filling. Common examples include the UCC’s implied warranty of merchantability, a reasonable price or time when none is stated, and the implied covenant of good faith and fair dealing, read into every contract to prevent either side from acting to deprive the other of the benefit of the bargain.

Wood v. Lucy, Lady Duff-Gordon is Cardozo’s classic illustration of gap-filling through an implied obligation. A fashion designer gave Wood the exclusive right to market her endorsements and split any resulting profits — but the agreement never actually said Wood had to make any effort to market anything at all. When Lady Duff-Gordon endorsed products through someone else instead, she argued the contract imposed no real obligation on Wood, so there was nothing to breach. Cardozo disagreed: an exclusive arrangement like this only makes sense if Wood was implicitly promising to actually use reasonable efforts to sell her endorsements — the court filled that obvious gap rather than let the whole arrangement collapse into an empty, one-sided illusion of a contract.

Example. Peter agrees to buy 100 chairs from John but the contract never states a delivery date. Rather than the deal failing for indefiniteness, a court will fill that gap with a reasonable time based on the circumstances. Separately, if John starts quietly shipping Peter chairs with broken legs — technically still “chairs” — the implied covenant of good faith and fair dealing stops John from hiding behind that technicality to deprive Peter of the usable chairs he actually bargained for.

Not every contractual obligation works the same way. A promise that’s broken gives the other side a claim for damages, but generally doesn’t excuse their own performance. A condition — an event that must occur before a duty to perform arises — is different: conditions generally must be strictly satisfied, and failing to meet one can excuse the other party’s performance entirely, not just create a damages claim. The same sentence can sometimes be read either way, which is exactly why the distinction is so heavily tested.

Example. John’s contract with Peter says, “John promises to paint Peter’s house, and Peter promises to pay John $3,000.” If John simply paints late, that’s a broken promise — Peter may have a damages claim, but he generally still owes something. Now compare: “Peter shall pay John $3,000, provided that John completes the painting by June 1st.” Here, John finishing by June 1st is a condition on Peter’s duty to pay. If John finishes on June 3rd instead, Peter’s duty to pay may never arise at all — not just be reduced by damages — because the condition was never strictly satisfied.

Conditions themselves come in three timing flavors, and mixing them up is a common mistake: a condition precedent must happen before a duty even arises (John must finish painting before Peter’s duty to pay exists at all); a condition concurrent requires both sides to perform at essentially the same moment (handing over keys and payment at a closing); and a condition subsequent cuts off a duty that already existed once a later event occurs (an insurance policy that terminates coverage if a claim isn’t filed within a stated period after a loss). Courts also lean toward reading ambiguous language as a promise rather than a condition where reasonably possible, since conditions carry the harsher, all-or-nothing consequence.

Luttinger v. Rosen shows a condition precedent doing exactly what it’s supposed to. Buyers agreed to purchase a house, expressly conditioned on obtaining mortgage financing at no more than 8.5% interest — a rate that, given market conditions at the time, simply wasn’t available anywhere, even though the buyers made a genuine, good-faith effort to find it. The court held their duty to buy the house never arose at all: because the financing condition was never satisfied, and the buyers hadn’t caused that failure themselves, they were entitled to walk away and recover their deposit — not merely to a reduction in price or a damages claim, the harsher, all-or-nothing consequence conditions carry.