If the purpose of a comprehensive contractual term is to exclude tacit terms, it should be ensured that the wording of the entire contractual term is sufficiently precise to ensure that that intention is clearly stated. In the case of Exxonmobil, it was the explicit reference to “use” that allowed one of the parties to rely on the entire contractual clause in order to prevent the effect of the terms by using them. In Exxonmobil Sales and Supply Corporation vs. Texaco Limited,1 a full contractual clause excluded implied terms of use or habit. In this case, the clause provided: 2 The purpose of such a clause is to ensure that only the provisions contained in the written contract constitute the agreement between the parties. In certain circumstances, there may be pre-contractual exchanges, assurances or statements on which a party wishes to rely. In this case, it may be more advantageous to waive the insertion of a provision. If the clause is inserted, all pre-contractual declarations that that party wishes to avail itself of should be included in the contract itself. They agreed that they were not trustees in the negotiations and that “this agreement replaces all prior written and oral agreements and understandings.” If, for any reason, the prior agreement is not explicitly included, this prior agreement may, in certain circumstances, give rise to a legally binding obligation, notwithstanding the fact that the contract contains a full contractual clause. This is due to the doctrine of waiver by agreement, which was recently investigated in relation to entire contractual terms in Mears Ltd v Shoreline Housing Partnership Ltd3. In 2008, they signed a cooperation agreement that succeeded the agreement. 1 Merger clauses are also referred to as “integration clauses” or “full contractual clauses”..

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