A listing agreement is a legally binding contract between a homeowner and the real estate agent or broker who will be listing the property for sale. Dual Agency is when you will be representing both parties in the same transaction and act as a fiduciary for both.A contractual agreement under which the listing broker acts as the agent or as the legally recognized non-agency representative of the seller(s). Treat all clients honestly. 2. When you sign this Agreement, you grant that agent the exclusive right to market, list, and sell your home for a specified period, usually 2-6 months. A contractual agreement under which the listing broker acts as the agent or as the legally recognized non-agency representative of the seller(s). What's in the Agreement? You and your Realtor will likely review this contract in detail and fill it out together. As a general rule, you should not start working with a seller without first having them sign this document.