A brief sets the boundaries of the job before the camera turns on: what the product does, who the video is talking to, the points that must be said (a claim, a promo code, a disclosure), the format (talking head, unboxing, voiceover), the length, and the file specs the brand needs back. It is not a script, and a good brief says so directly.
The most common failure runs in either direction. A brief with no detail leaves a creator guessing what the brand actually wants and invites a round of frustrated revisions. A brief written as a full, word-for-word script tends to produce content that sounds recited on camera, working against the entire reason brands want UGC in the first place. The middle ground states the must-haves and leaves delivery to the creator.
On Socialync's job board, the brief lives on the campaign listing along with the pay, the floor, and the usage rights, so a creator reads the full scope of the job before ever applying.