Every company says it has a brand voice. Ask what it is and you usually get adjectives: friendly, confident, smart but not stuffy. Then a draft comes back and the head of marketing says "this doesn't sound like us," and nobody can say which sentence is wrong or why.
That is a vibe, not a voice. A vibe lives in one person's head and can only be checked by that person. A voice that survives more than one writer, whether the writer is a freelancer, a new hire or an AI agent, has to be written down as something closer to a spec: specific, testable, and short enough to actually read.
Why adjectives fail
"Friendly" is not an instruction. Friendly how? Exclamation marks? First names? Jokes? Emojis? Two writers given the word "friendly" will produce two different posts, and both can reasonably claim they followed the brief.
Adjectives describe the effect you want on the reader. Rules describe what the writer does to get there. You need the second kind, because the writer can only control the second kind.
A good test for any line in a voice guide: could two people disagree about whether a draft follows it? If yes, it is still an adjective. Keep rewriting until the answer is no.
- "Be concise" fails the test.
- "Keep paragraphs to three sentences or fewer" passes.
- "Sound confident" fails.
- "Do not hedge with 'might', 'perhaps' or 'arguably' unless the uncertainty is real" passes.
The four layers of a voice spec
Most voice guides that work end up covering four layers, whether they name them or not.
1. Who we are talking to
One or two sentences about the reader, specific enough to change word choices. "Small business owners" is weak. "Owners of two to twenty person service businesses who do their own marketing on Sunday evenings" tells a writer what the reader already knows, what they do not have time for, and what kind of example will land.
2. How we sound
This is where the adjectives go, but each one has to be cashed out into behaviour.
| Instead of | Write |
|---|---|
| Friendly | Address the reader as "you". Contractions are fine. No exclamation marks. |
| Expert | Use the correct technical term, then explain it once in plain words. |
| Direct | Lead with the answer. No scene-setting opening paragraph. |
| Honest | Say when our product is the wrong fit. Never claim a number we cannot source. |
3. Words we use and words we avoid
The most useful part of most voice guides, and the most often skipped. Write down your own names for things ("workspace", not "account"), the jargon your customers use and the jargon they hate, and the filler phrases that make copy sound generic.
Be literal. "Avoid corporate speak" is an adjective again. "Never write 'leverage', 'synergy', 'robust' or 'best-in-class'" is a rule.
4. Mechanics
Heading case. Oxford comma or not. How numbers are written. Whether dashes are allowed. Whether you link to sources. These feel trivial until a reader notices the same site uses three different heading styles in one week.
How to write it in an afternoon
You do not need a workshop. You need your best existing writing and about three hours.
- Collect five pieces you are proud of. Posts, emails, landing pages, anything customers read.
- Collect three pieces that felt off. A draft someone rewrote, a competitor post you dislike, AI copy that made you wince.
- Compare them sentence by sentence. For every difference you can see, write a rule that would have produced the good version. "They open with a question. We open with the answer."
- Cut the list down. Keep the rules that would change a draft. Drop the ones any competent writer already follows.
- Test it on someone new. Hand the rules, and nothing else, to a person who has never written for you. Ask them for a short piece. Every place their draft still feels wrong is a rule you have not written yet.
Rules that are easy to follow and easy to check
The best rules share a shape: one behaviour per line, stated as something to do or not do, with a reason when the reason is not obvious.
A few that tend to earn their place:
- Never use em dashes. Use a comma, colon, or a second sentence instead.
- Start with the substance. Do not open with a paragraph about why the topic matters.
- Keep paragraphs to three sentences or fewer.
- Write headings in sentence case.
- Back every significant claim with a concrete example, number or scenario.
- Link to a primary source for every statistic.
- Close each section with something the reader can act on, not a summary.
Notice that none of these say "sound like us." Together they make a draft sound like somebody in particular.
Why this matters more when an AI writes the draft
A human writer absorbs a vibe over months: they read the old posts, they get edited, they pick it up. An AI agent gets exactly what you put in front of it, every time, and nothing else. Adjectives go in and averaged, generic prose comes out.
That is not a weakness to work around. It is the reason a written spec pays off. A rule written once is applied on every draft, not just the ones the voice owner had time to review. And because the rule is written down, a draft that breaks it is a clear failure rather than a matter of taste.
Two caveats worth being honest about:
- Rules are instructions, not a linter. A model follows clear rules well, but it can still slip. Keep the human read before publishing, and treat a repeated slip as a sign the rule needs rewording.
- Rules cannot supply facts. A voice spec says how to talk, not what is true. Keep facts about the business, such as what you sell and who buys it, in a separate document the writer also reads.
In RankMill those two things live in two places. Writing rules sit on each project, one rule per line, set when the project is created. The website profile, which the research agent writes and you can edit, holds the business facts and has its own "Voice & tone" section. Every agent that writes copy reads both, and where they disagree the writing rules win.
Keep the spec alive
A voice spec is never finished. Three habits keep it honest:
- When you rewrite a sentence in someone's draft, ask which rule would have prevented it. If none would, write one.
- When a rule is never broken, check whether it is doing anything. Rules that every writer follows anyway are noise that hides the rules that matter.
- Read it once a quarter against your newest work. Voices drift, usually for good reasons. The spec should follow the drift on purpose rather than by accident.
The short version
- Adjectives describe the effect, rules describe the behaviour. Write rules
- If two people could disagree about whether a draft follows a line, rewrite the line
- Cover the reader, the sound, the vocabulary and the mechanics
- Build the rules by comparing writing you love with writing that felt off
- Test the spec on someone who has never written for you
- Keep facts and voice in separate documents
- Treat every repeated edit as a missing rule
"Sounds like us" is a fine goal. It is a terrible instruction. Write down what it means, and it can be followed by anyone you hand it to.