How to brief an AI tool
without losing your brand voice.

Why AI output drifts generic

A language model will happily write in “your” voice — but only if you’ve actually told it what that voice is. Left to its own devices, it defaults to a safe, competent, slightly corporate middle ground, because that’s the statistically unremarkable choice across everything it’s seen. Vague instructions (“make it sound like us”, “keep it professional but friendly”) don’t give it anything to aim at, so it aims at the average.

What a real brand-voice brief needs

Four things, in order of how often they get skipped:

1. Real examples of your own writing, not a description of your writing. “We’re direct and a bit dry” means less than three actual paragraphs you’ve written that are direct and a bit dry. Paste them in.
2. Specific words and phrases you use — and specific ones you don’t. “Never use ‘revolutionary’, ‘game-changing’, or exclamation marks” does more work than “keep it understated”.
3. The reader, named specifically. Not “small businesses” — “a sole trader who’s been burned by one bad agency already and is sceptical of anyone who sounds too polished.” The sharper the reader, the less generic the output.
4. What a bad version would sound like. Describing the failure mode (“don’t let this turn into a listicle with em-dashes everywhere”) is often more useful than describing the target, because it rules out the model’s defaults directly.

A brief that actually works, in practice

A workable structure, every time:

• Who it’s for: one or two sentences, specific enough that a generic answer obviously wouldn’t fit.
• What it needs to do: the one job this piece of writing has — not three.
• Three examples of our voice: pasted in full, not summarised.
• Three things to avoid: words, structures, or tones that keep creeping in and aren’t us.
• Length and format: a number, not “concise”.

That’s five short sections. It takes longer to assemble the first time than it does to write the brief itself — and it’s reusable indefinitely once it exists.

The part that still needs a human

A good brief gets you a strong first draft, not a finished one. The review step that actually matters isn’t “does this sound roughly right” — it’s reading it out loud. Voice drift is far easier to hear than to spot on the page, and it’s the fastest way to catch the moment a draft has quietly slipped back into generic.

There’s a second check worth building in: once a draft reads well aloud, run it against the rest of that brand’s own written material — other guides, landing pages, past articles — through an AI workflow trained to flag inconsistency. A line can sound right in isolation and still be drifting from the voice everything else carries. Reading aloud catches tone within a document; this catches drift across them.

Keep a short running list of edits you make to AI drafts — phrases you keep cutting, structures you keep breaking up. That list is your actual brand voice, discovered in reverse, and it’s one of the most useful things to fold back into the next brief.

FAQs

Why does AI-generated marketing copy sound generic?

Because a model defaults to a safe, statistically unremarkable middle ground unless you tell it specifically what your voice is. Vague instructions like “make it sound like us” don’t give it anything concrete to aim at.

What should a brand-voice brief include?

Real examples of your own writing (not a description of it), specific words and phrases to use and avoid, a reader described specifically rather than generically, and what a bad version would sound like.

How long does it take to build a reusable brand-voice brief?

Longer to assemble the first time than it does to write the piece itself — five short sections: who it’s for, what it needs to do, three voice examples, three things to avoid, and length and format. It’s reusable indefinitely once it exists.

How do I check whether an AI draft has drifted off-brand?

Read it out loud — voice drift is far easier to hear than to spot on the page. Then check it against your own past material for consistency, since a line can sound right in isolation and still be drifting from the voice everything else carries.