Brand Voice Template for AI (voice.md)

A brand voice template for AI describes how a client sounds in a form an AI can actually follow: contrasts instead of adjectives, words to use and avoid, rules, and real examples of on-voice and off-voice writing. The free template below, voice.md, is one Markdown file per client. Add it to the client's Claude Project, custom GPT or Gemini Gem, and drafts start sounding like the client instead of like generic AI.

Why brand books don't work for AI

A brand book is written for designers and humans who already know the brand. An AI reads it literally and falls back on its own default style whenever the guide is vague. That's why AI drafts for very different clients often end up sounding alike.

Three things go wrong:

• Adjectives without contrast. Every brand says it is "friendly, professional and innovative". Without saying what it is not, the AI can't tell one client's "friendly" from another's.
• Visual guidelines mixed with writing rules. Logo spacing and color codes take up pages, and the few lines about writing get lost.
• No examples. One real sentence teaches more than a paragraph of description, and most brand books have none written for the AI to imitate.

A voice guide for AI fixes this with contrasts, concrete rules and paired examples.

The template

Copy everything below into a file named voice.md, one per client. Replace the bracketed text and delete what doesn't apply.

# [Client name] — brand voice for AI

Owner: [name] · Last reviewed: [YYYY-MM-DD] · Version: [1]

## How to use this guide
- Follow this guide for anything written as or for [Client name].
- When the guide and your usual style disagree, the guide wins.
- Match the examples more closely than the descriptions.

## Voice in one sentence
[Client name] sounds like [a specific kind of person] talking to [audience] about [topic]. Example: "a senior engineer explaining a tool to a busy colleague".

## This, not that
| We are | We are not |
| --- | --- |
| [Plain] | [Simplistic] |
| [Confident] | [Arrogant or salesy] |
| [Warm] | [Cute or over-familiar] |

## Tone by situation
- Website and ads: [e.g. short, benefit first, no jargon]
- Social posts: [e.g. conversational, one idea per post]
- Emails to customers: [e.g. personal, first name, signed by a person]
- Bad news or apologies: [e.g. direct, no excuses, say what happens next]

## Vocabulary
- Words we use: [...]
- Words we never use: [...]
- Product and brand names, spelled exactly: [...]
- How we refer to customers: [e.g. "you", never "users"]

## Style rules
- Point of view: [we / you / third person]
- Sentence length: [e.g. short; one idea per sentence]
- Spelling: [US / UK / Canadian English, or other language variant]
- Capitalization in headings: [sentence case / title case]
- Punctuation habits: [e.g. no exclamation marks, Oxford comma]
- Emojis: [never / social only / ...]
- Numbers: [e.g. digits for 10 and up]

## Examples: on-voice vs off-voice
### [Situation, e.g. product announcement]
- On-voice: "[...]"
- Off-voice: "[...]"
- Why: [one line]

### [Another situation]
- On-voice: "[...]"
- Off-voice: "[...]"
- Why: [one line]

## Approved samples
- [Title or URL of a piece the client approved] — [why it is a good model]

---
Template: voice.md by SagaJoe (sagajoe.com/learn/brand-voice-template) · CC BY 4.0

Free to use, adapt and share under CC BY 4.0. Keep the credit line at the bottom of the file.

How to fill it in 30 minutes

Build the voice guide from the client's best real writing, not from a blank page. Clients are better at recognizing their voice than describing it.

1. Collect five pieces the client loves. Their best-performing email, a home page they're proud of, a post that got real replies. Ask the client directly: "Which of your writing sounds most like you?"
2. Collect one or two they dislike. Off-voice examples are as useful as on-voice ones, and clients usually remember exactly what they hated.
3. Write the one-sentence voice. Who would naturally write those five pieces? Describe that person, not the brand.
4. Fill "This, not that". For each adjective the client uses about itself, write the failure on the other side: plain, not simplistic; confident, not salesy.
5. Pull the vocabulary from the samples. Words that keep coming back go in "use"; words the client corrected in past drafts go in "never".
6. Write two or three example pairs. Take one real on-voice sentence and write the generic AI version of the same message next to it.
7. Have the client approve it. Send it as a one-page document. A voice guide the client signed off on settles future debates about tone.

A filled example

The same fictional client as in the client.md example: Acme Analytics, a B2B software company.

# Acme Analytics — brand voice for AI

Owner: Julie Tremblay · Last reviewed: 2026-11-03 · Version: 3

## How to use this guide
- Follow this guide for anything written as or for Acme Analytics.
- When the guide and your usual style disagree, the guide wins.
- Match the examples more closely than the descriptions.

## Voice in one sentence
Acme sounds like a senior marketer explaining a useful tool to a busy colleague: practical, plain, a little dry.

## This, not that
| We are | We are not |
| --- | --- |
| Plain | Simplistic |
| Confident | Hype-y or salesy |
| Helpful | Lecturing |
| Dry humor, rarely | Jokes, puns or memes |

## Tone by situation
- Website and ads: one benefit per sentence, no jargon
- Social posts: one idea, written like a note to a peer
- Customer emails: first name, signed by a real person, under 120 words
- Bad news: say what happened, what we're doing, when it's fixed

## Vocabulary
- Words we use: "your team", "set up", "see", "in minutes"
- Words we never use: "users", "leverage", "revolutionary", "seamless", "game-changer"
- Product name: "Acme Insights" (never "the Acme platform")
- Customers are "you" or "your team", never "users"

## Style rules
- Point of view: we and you
- Sentence length: short; one idea per sentence
- Spelling: US English
- Headings: sentence case
- No exclamation marks; Oxford comma
- Emojis: never

## Examples: on-voice vs off-voice
### Product announcement
- On-voice: "You can now see which features your customers use most, without asking a developer."
- Off-voice: "We're thrilled to unveil a revolutionary new feature that will transform how users leverage data!"
- Why: one concrete benefit, no hype, no "users".

### Price change email
- On-voice: "Starting December 1, the Starter plan is $49/month. Here's what's included, and what to do if you have questions."
- Off-voice: "Exciting news! We're updating our pricing to serve you even better!"
- Why: state the change plainly; never dress bad news up as good news.

## Approved samples
- Home page headline, October 2026 — shortest, clearest statement of the product
- "Your first dashboard in 10 minutes" email — the model for onboarding emails

---
Template: voice.md by SagaJoe (sagajoe.com/learn/brand-voice-template) · CC BY 4.0

How voice.md fits with client.md and your AI workspaces

Keep two files per client: client.md for facts, voice.md for how the client sounds. They change at different speeds: facts weekly, voice a few times a year.

• Small clients: the short Voice section inside client.md is enough. Switch to a separate voice.md once voice needs more than about ten lines.
• In the workspace: add both files as knowledge in the client's Claude Project, custom GPT or Gemini Gem, and add one line to the instructions: "Follow voice.md for tone and wording."
• Agency house style: if your agency has its own style rules, keep them in a separate shared file and let the client's voice.md override them.

The voice test

Check the guide works before relying on it. Ask the AI, inside the client's workspace, for three short pieces:

1. A two-sentence product announcement.
2. A reply to an unhappy customer.
3. A social post about something ordinary, like a team update.

Then run a blind test: mix the three AI pieces with three real pieces from the client, remove the names, and ask a teammate (or the client) to pick out the AI ones. If they can spot them easily, find what gave them away (a banned word, a tone that's too excited, a sentence that's too long) and add a rule or an example pair to voice.md.

Repeat the test whenever a new person starts writing for the client. It doubles as a five-minute onboarding to the client's voice.

FAQ

What is a brand voice template for AI?

A short document that describes how a brand writes, in a form AI tools can follow: contrasts, vocabulary, style rules and paired on-voice and off-voice examples.

How is it different from a brand book?

A brand book covers visuals and is written for people who already know the brand. A voice template for AI covers only writing, and replaces vague adjectives with contrasts and examples.

Why does AI content from different clients sound the same?

When voice instructions are vague, the AI falls back on its own default style. Contrasts ("plain, not simplistic") and example pairs give it something specific to match.

How many examples should a voice guide include?

Two or three on-voice and off-voice pairs, plus two approved samples. More examples help less than better-chosen ones.

Should the voice guide be part of the client brief?

For small clients, a short Voice section in client.md is enough. Use a separate voice.md once voice needs more than about ten lines.

How often should I update a brand voice guide?

Review it quarterly or after a rebrand, and add a rule whenever the team corrects the same tone problem twice.

Voice stays put. Facts don't.

A client's voice changes a few times a year; their prices and offers change every month. SagaJoe keeps the fast-moving half current: it builds each client's brief from their website, re-checks it weekly, and sends one note with only what changed. See how it works.

Keep learning

• Client brief template for AI (client.md)
• How to set up one AI workspace per client
• Context engineering for agencies: the complete guide