A marketing team turned on a writing assistant and, within a month, the site, the emails, and the sales deck had converged on the same temperature. Helpful. Smooth. Unwilling to say a hard sentence. Nothing was false. Nothing was theirs. Customers could not have told you which company had sent it, and neither could the team, after a while.
They had not lost a model. They had stopped deciding.
a voice is a set of refusals
Brand voice is not a list of adjectives in a PDF. It is the sentences you will not ship. We do not open with a throat-clearing clause about today's landscape. We do not call a feature powerful. We do not hide a tradeoff under excited. Write those down as examples, with the bad sentence and the one you would actually send.
Then give the model the examples. A prompt that says be concise and human is how every company on earth now sounds. A prompt that includes the last thing you rewrote, and why, is a standard.
If nobody is allowed to change the draft, you do not have a voice. You have a default.
name the editor
Someone owns the words that leave the building. Not a committee. A person who can reject a paragraph that is merely fine. The model can get you to a first pass before lunch. It cannot care whether this sentence is one you would say out loud to a customer.
Use it for the blank page. Do not use it as the last reader.