The term “agreement” is broader than “contract” because “any contract is an agreement, but conversely, it is not possible.” Indeed, all contracts contain the elements of the agreement, i.e. supply and acceptance, but not all agreements contain the main element that constitutes a contract, that is, legal applicability. So we can say that any agreement is not a contract. An agreement is an agreement between two or more parties. A contract is a particular type of agreement which, by its terms and elements, is legally binding and enforceable in court. To reach an agreement, the parties only have to agree on their relative rights and obligations, often referred to as the “meeting of minds.” Contracting requirements are more precise and relatively stringent. A contract must contain the following essential elements: if the terms of the contract are uncertain or incomplete, the parties cannot have reached an agreement in the eyes of the law.  An agreement is not a contract and the inability to agree on key issues that may include price or security elements may lead to the failure of the entire contract. However, a court will endeavour to implement commercial contracts where possible by excluding an appropriate design of the contract.
 In New South Wales, even if a contract is uncertain or incomplete, the contract may remain binding on the parties if a sufficiently secure and comprehensive clause requires the parties to submit to arbitration, negotiation or mediation.  However, the conclusion of the contract should not be taken into account in the context of the contract, as is currently the case. For example, in the first English case of Eastwood v. Kenyon , the guardian of a young girl, took out a loan to educate her. After her marriage, her husband promised to pay off the debts, but the loan was considered a historical value. The inadequacy of previous considerations is related to the existing customs rule. In the first English case of Stilk v. Myrick , a captain promised to divide the salaries of two deserters among the rest of the crew if they agreed to set sail; However, this promise was found to be unenforceable, as the crew was already in charge of the ship`s navigation.
The existing customs rule also applies to general legal obligations; For example, the promise not to commit an unlawful act or crime is not enough.  The contracting party to whom the offer is made or proposed consents to mutual consideration in this regard, the offer is deemed accepted, resulting in a commitment.