Capturing your brand voice: a document both people and AI understand
“Our tone is professional yet approachable” appears in almost every brand manual and helps nobody — neither a new colleague nor a language model. What helps are examples of right and wrong, banned words, and three decisions.
In short
- Adjectives do not describe a voice. Paired examples of right and wrong do — they are the core of the document.
- Six sections are enough: paired examples, banned words, sentence structure, form of address, handling uncertainty, and what you never claim.
- A style document is simultaneously onboarding material for new colleagues and an attachment for every writing prompt.
- Two pages are enough. Anything longer gets neither read nor attached.
The test for a style document is simple: give it to someone who does not know your company and have them write a paragraph. If it sounds like you, the document works. If it sounds like any company, it is made of adjectives.
Why adjectives do not work
"Professional, approachable, competent, on equal terms" — those four words appear in almost every brand manual and exclude nothing. No company describes itself as unprofessional and distant.
A language model has the same problem as a new colleague: it cannot derive anything from those words, because they force no decision. It only becomes usable when two versions of the same sentence sit side by side with a note saying which one is right.
The six sections
1. Paired examples — the core
Ten to fifteen pairs, each two versions of the same content, marked "like this" and "not like this". From real texts, not invented ones.
Example:
Not like this: "We are revolutionising how companies grow."
Like this: "We build marketing processes that run without a team of your own."
2. Banned words
A concrete list. Ours includes: revolutionary, holistic, innovative, state of the art, game changer, "in today's fast-moving business world".
Why: a ban list is the only style rule that can be checked mechanically — by people and by tools alike.
3. Sentence structure
Average sentence length, whether subordinate clauses are welcome, whether exclamation marks appear, whether questions are allowed as headings.
Example: "15 to 25 words per sentence. No exclamation marks. No exclamation as a heading."
4. Form of address and perspective
Formal or informal, "you" or "we", and whether it changes by text type. A decision, not a recommendation.
Why: the point most often inconsistent — especially when several people write.
5. Handling uncertainty
How do you write when you do not know something for certain? Conceal it, hedge it, or name it? That shapes the effect more strongly than any adjective.
Example: "Uncertainty gets named: 'experience-based estimate, not a survey.' No figure without a source."
6. What we never claim
Statements others in your field make and you deliberately do not. The section that separates a voice most sharply from others.
Example: "No time savings as a percentage without a reference. No promises of success. No customer quote without approval."
Worth knowing
Section six — what you never claim — has the strongest effect in practice, although it appears in almost no brand manual.
The reason: a voice is created not by what someone says but by what they leave out when everyone else says it. Being the only one in a field full of percentage promises who names no percentages makes you recognisable by that — more clearly than by any phrasing.
Creating the document — in three hours
- Collect ten of your own texts you like, and five you do not. From your own communication, not from other people's.
- Name the differences. What do the good ones do differently? Sentence length, directness, figures, restraint? Every observation becomes a paired example.
- Draw the ban list from the bad ones. Which words appear there and not in the good ones?
- Make the three decisions: form of address, sentence length, handling uncertainty.
- Test it: someone with no prior knowledge writes a paragraph using it. Does it sound like you?
The test in step five is the only one that counts — and it is almost always left out. A sentence you wrote yourself always reads clearly to you.
If the test paragraph does not sound like you, what is usually missing is paired examples. Five additional pairs work more reliably than any refinement of the description. Descriptions leave room; examples do not.
Using the document with a language model
Two routes, depending on the tool:
- Store it as a standing instruction where that is possible. It then applies to every request without needing to be attached each time.
- Attach it to every writing prompt. The style frame belongs at the end of the prompt, not in the middle — details at the close are taken into account more reliably.
Help me capture our brand voice as a style document. Texts that sound like us (please read carefully): [paste 3 to 10 of your own passages] Texts that do not sound like us: [paste 3 to 5 passages – your own older ones or other people's] Tasks: 1. Name the concrete differences between the two groups: sentence length, directness, handling of figures, form of address, imagery, degree of restraint. Support every observation with a quotation. 2. Turn that into 10 to 15 paired examples, "like this / not like this". Use content from my texts, not invented material. 3. Draw a list of banned words and phrases from the second group. 4. Phrase the three decisions: form of address, sentence structure, handling uncertainty. 5. Propose a section "what we never claim" – based on what is conspicuously absent from my texts. Keep the result to at most two pages. Do not use general adjectives such as "professional" or "approachable".
In closing
A style document that works consists mostly of examples and bans — not descriptions. That makes it simultaneously onboarding material for new colleagues and an attachment for every writing prompt.
The effort runs to about three hours, and the decisive step is the last one: someone with no prior knowledge writes a paragraph with it. If it sounds like you, the document is finished. If it sounds like anyone, paired examples are missing.
Common questions
How do you define a brand voice?
Not through adjectives but through ten to fifteen paired examples — two versions of the same content, marked "like this" and "not like this". Add a list of banned words, decisions on sentence structure and form of address, an approach to uncertainty, and a section on what you never claim.
Why are adjectives like "professional yet approachable" not enough?
Because they exclude nothing — no company describes itself as unprofessional and distant. Neither a person nor a language model can derive a decision from them. Only two versions of the same sentence side by side, with a note on which is right, force a decision.
How long should a style document be?
Two pages. Anything longer gets neither read by new colleagues nor attached to every request to a language model. Two pages fit into any prompt and can be read through in twenty minutes.
How do you give the document to a language model?
Stored as a standing instruction where possible, otherwise attached to every writing prompt — at the end rather than the middle, because details at the close are taken into account more reliably. The paired examples belong in full, not summarised.
How do you know the document is any good?
Through a test: someone who does not know the company writes a paragraph with it. If it sounds like you, the document works. If it sounds like any company, paired examples are missing — five additional ones work more reliably than any refinement of the description.
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