A brief usually tells you what the client wants changed. It does not always tell you everything that may need attention.
Sometimes there is a reflection that feels slightly wrong. A fold in the clothing that pulls the eye too much. A strand of hair that breaks the shape of the face. A small makeup issue, an uneven edge, a distracting object in the background. None of it is mentioned in the brief, but once you see it, you have to decide what to do.
This is where retouching becomes less mechanical.
If every unmentioned detail is corrected automatically, the image can quickly become overworked. Some irregularities are part of the photograph. Some are too small to matter. Others may be intentional choices by the photographer or stylist.
At the same time, ignoring an obvious distraction simply because it was not listed in the brief does not always make sense either.
So I usually look at these things in context. Does the detail actually interrupt the image? Is it consistent with the rest of the series? Would changing it affect something else? Is it a safe correction, or does it move into an area where the client should make the decision?
Over time, you become better at separating what needs attention from what only attracts your professional eye because you know how to fix it.
A brief gives direction. It does not replace judgment.
Part of the job is noticing what was not mentioned, and then deciding whether it should stay that way.