A development agreement shall specify the duration of the agreement, the permitted uses of the property, the density or intensity of use, the maximum height and size of proposed buildings, and provisions for reservation or dedication of land for public purposes. The development agreement may include conditions, terms, restrictions, and requirements for subsequent discretionary actions, provided that such conditions, terms, restrictions, and requirements for subsequent discretionary actions shall not prevent development of the land for the uses and to the density or intensity of development set forth in the agreement. The agreement may provide that construction shall be commenced within a specified time and that the project or any phase thereof be completed within a specified time. No such agreement shall conflict with the requirements of the zone in which the project is located at the time the agreement is approved, and all such agreements must be in conformity with the General Plan as it exists at the time the agreement is approved.