an agreement to agree does not constitute a contract law

[dirk]

пожалуйста помогите перевести этот юридический термин. Буду очень благодарна )))
If the terms of the contract are uncertain or incomplete, the parties cannot have reached an agreement in the eyes of the law.[19] An agreement to agree does not constitute a contract, and an inability to agree on key issues may cause the entire contract to fail.

Короче, я не совсем понимаю вот это An agreement to agree does not constitute a contract

Спасибо