A contractual brief outlines an agreement between a media company and client where the company agrees to complete a specific task by a certain deadline for a set fee. The contract legally binds both parties, with the company promising to deliver the work on time and the client providing payment once completed. Key advantages include both parties understanding their obligations and the company being held accountable if they fail to deliver. However, the contract cannot be renegotiated if circumstances change, so it is important to carefully review all details before signing.