Documenting the functional requirements provides several important benefits to the organisation and to the process of developing a solution. Assumptions are future situations beyond the control of the project,. [provide a list of contractual or task level assumptions and/or constraints that are preconditions to preparation of the frd. It allows you to apply a ratings system to your requirements, so you have the visibility (into the value, status, and description of each requirement) that’s. A functional specification document (fsd), also known as a functional requirements document (frd), is considered by many project management and software.