In accordance with Illinois law, if the Property contains one (1) to four (4) dwelling units, the Seller must complete the Property Disclosure. A listing agreement is a contract between homeowners and brokers that legally establishes how a realtor will find a property buyer on the seller's behalf.Customer: I signed a listing agreement with a realtor to sell my house. We signed on Saturday evening. The purpose of the Listing Agreement License Language is to have the seller grant to the broker the rights necessary for the broker to use the listing content. The listing agreement is a contract that lays out specific, agreedupon terms, giving the real estate agent permission to market a home to buyers. The Listing Agreement Language also authorizes the broker to list the property in the MLS and allow the MLS to make IDX listings available to other brokers. The co-listing arrangement should be disclosed in the listing agreement, and also in the remarks section on the MLS. The agreement is actually a contract between the managing broker and the seller.