A Master Service Agreement is a contract that sets up the fundamental terms for future business activities between two or more parties. This Primer provides a general overview of City contracting processes and solicitation methods.TABLE OF CONTENTS. Page. Master Service Agreement. A master service agreement (MSA) is a fundamental contract outlining the scope of the relationship between two parties. A master agreement is a document that outlines the terms and conditions of an agreement between two or more parties. A professional services agreement can be used for a one-time service as well as ongoing services. It can also be used as a master level agreement.