Writing a voice and style guide for AI tools

I'd been working on a guide to make my AI-assisted writing sound more natural. Then something happened in my team that turned it from a personal project into something worth sharing.

Why I wrote it

One of my team put together a quick draft document for a senior manager. The feedback was that it looked like it had been written by AI.

We have efficiency targets built around using AI. So this came across as a very mixed message: use AI to be more efficient, but make sure it doesn't look like you used AI to write it.

So I took what I'd learned for my own writing and turned it into a version I could share with the team. The aim was to help each of them make their writing sound more like them. Not like me, and not like AI.

How I built it

I started with ideas I'd been collecting for a while. I subscribe to Nate B. Jones's newsletter on practical AI use, and I'd saved other useful articles and videos in Recall. None of it was a ready-made answer, but together it gave me a structure.

Then I made it specific to me. I used Claude and ChatGPT together, over several rounds, to analyse my own writing: LinkedIn posts, journal entries, old documents and my past AI conversations. Only things I had written myself counted as evidence of my voice. Course notes, books and AI-generated reports were used for context only.

The analysis produced measurable detail. My LinkedIn sentences average about 12 words, and roughly four in ten are eight words or fewer. A rule like that gives a tool something specific to follow.

The work version needed a different approach. I asked Copilot to take my personal guide and produce a version based on how Copilot applies instructions. A style guide doesn't work the same way in every tool, so it made sense to let the tool that would use it shape it.

What's in it

The full guide covers more than writing. It also sets out how I want documents, slides and dashboards to look. The writing parts are the ones that matter for AI tools:

• Voice. How I want to come across, with examples of what that does and doesn't sound like.
• Mechanics. British English, no em dashes, sentence length and how I use lists and questions.
• Things to avoid. Hype openings like "In the age of AI…", engagement bait, invented anecdotes and false certainty.
• Tone by context. Different defaults for an email, a brief, a LinkedIn post and a CV.
• A clean-up checklist. Cut filler, puffery and vague claims, then stop after one pass.
• Hard limits. The tool must never invent my experiences, opinions or figures. If something's missing, it asks me.

The guide is explicit that adjectives on their own aren't enough. Telling a tool to be "grounded" gives it little to act on. Showing it one sentence that sounds like me and one that doesn't gives it something to work with.

Read the shareable version of my guide →

What happened with my team

I shared the work version with my team. It isn't a guide to hand to Copilot as it stands. Each person works through it with Copilot to create their own voice and style guide. The colleague whose draft had been described as looking AI-written did this before their next Copilot-assisted document. It was much better and read far more naturally.

That's one person's experience, not a controlled test. But it matched what I'd found myself. A bit of time spent explaining how you want to write makes a much bigger difference than the time it takes.

How to make your own

Don't copy mine. If you do, your writing will sound like me, which isn't much better than sounding like AI.

1. Gather your own writing. Pick five to ten pieces you're happy with and that you wrote yourself.
2. Ask a tool to describe your style. Ask it what you do, not what you should do: sentence length, openings, closings and words you use often.
3. Write down what you dislike. The phrases you keep deleting from AI drafts are a quick place to start.
4. Add examples. One passage that sounds like you and one that doesn't.
5. Set the limits. Tell the tool what it must never invent.
6. Test it. Give the same request to a tool with and without the guide, and compare the results.

Here's a blank template to start from:

# My voice and style guide

## Who I write for
- Main readers:
- What they need from me:

## How I want to come across
- Three or four words, each with one example of what it sounds like:

## Mechanics
- Spelling and language:
- Sentence and paragraph length:
- How I open and close:

## What I avoid
- Phrases:
- Habits:

## Examples
- A passage that sounds like me:
- A passage that doesn't, and why:

## Limits
- Never invent my experiences, opinions or figures. Ask me instead.

## Instructions for the AI tool
Follow this guide when drafting. Afterwards, check the draft against it
once and list anything you couldn't follow or need me to confirm.

Using it day to day

Paste the guide at the start of a chat, save it as a custom instruction, or attach it as a file. Then use a short brief for each piece of work: what you're writing, who it's for, your actual view, and the evidence you can use.

None of this retrains the model. It just tells the tool what good looks like for you.

What I'm still testing

The guide describes how I want to write. I haven't yet properly tested whether it reliably produces writing that sounds like me. The next experiment is to check it against pieces I've already accepted as mine, and I'll write that up here.