Which document serves as the legally binding agreement between the contractor and the client?

The contract serves as the legally binding agreement between the contractor and the client because it outlines the terms and conditions of the project, including the scope of work, payment schedules, timelines, and the responsibilities of both parties. By signing the contract, both the contractor and the client formally agree to the specified terms, creating a legal obligation that can be enforced in a court of law if necessary.

The project plan, while important for outlining the procedures and tasks needed to complete the project, does not constitute a legal agreement. The design specifications detail the technical requirements and standards for the project but do not establish the legal relationship between the parties. The change order is used to modify existing contractual terms or scope but is not the initial agreement that binds the contractor and client. Therefore, the contract is the fundamental document that establishes the legal framework for their working relationship.