[provide a list of contractual or task level assumptions and/or constraints that are preconditions to preparation of the frd. Use the following priority table. A functional specification document (fsd), also known as a functional requirements document (frd), is considered by many project management and software. The frd is produced by business analysts or sometimes the technical team in response to the business. The functional requirements document (frd) is a formal statement of a product's functional requirements.