What the Brief Doesn't Say

A brief describes what a client wants. It rarely describes what they need.
A typical brief for editorial photography contains locations, timings, required deliverables and a mood reference: usually a selection of images found elsewhere that approximate the feeling the client is after. It describes the outcome clearly enough. What it cannot describe is what the space actually is when nobody is performing for a camera, what the client cannot yet articulate about their own work, or what the photography will reveal that neither party could have anticipated before it was made.
The brief is written before the photographer has been inside the building. It is also written before the client has seen the building through the photographer's eyes, which is a different thing from having been in it every day for a year. The client knows the space better than anyone, and this familiarity has made certain things invisible to them: the quality of light at a particular hour, the detail that a visitor always pauses at, the corner nobody has thought to photograph because it is simply, obviously there.
This is the gap the commission lives in. The brief is the starting point for a conversation, not a specification for a result. A photographer who works only to the brief will produce images the client recognises. A photographer who works from the brief toward something the client could not have asked for will produce images the client did not know they needed until they saw them.
The best clients understand this and leave room for it. They write a brief specific enough to be useful and open enough to be surprised by. The worst briefs are the ones that have already decided what the photographs look like before anyone has picked up a camera.
Every commission worth taking ends somewhere the brief did not predict. That is not a failure of the brief. It is the point of commissioning someone to look rather than someone to illustrate.