What type of bond promises that the contract will stay within the bounds of the contract until completion?

A performance bond is a guarantee that the contractor will fulfill the obligations specified in the contract and complete the project within its established terms. This bond is essential because it protects the project owner against financial loss if the contractor fails to perform as agreed. Essentially, a performance bond ensures that the project will be completed satisfactorily and according to the contract stipulations, providing a level of security that the contractor will adhere to the agreed timeline, quality, and other conditions.

While other types of bonds serve different purposes, they do not specifically promise that the contract will remain within its terms until the project's completion. For instance, a bid bond assures the owner that the contractor will honor the bid if awarded, while labor and material payment bonds focus on ensuring that subs and suppliers get paid, rather than guaranteeing the project's completion. A surety bond is a broader category that can include performance bonds but does not specifically address the completion aspect. Thus, a performance bond is the most appropriate answer to the question at hand.