How to get Claude to write in your voice
Build a voice guide once — a document that captures your vocabulary, structural habits, and writing patterns — and stop editing AI drafts that sound like they were written by an LLM.
Most AI writing is recognizable from a hundred feet away. For example, triadic adjectives ("clear, concise, and compelling") and setup/payoff opening lines ("Here's the thing:") are all giveaways of an AI author. If you've ever asked Claude to draft something and then spent 20 minutes editing out everything that sounds like an LLM wrote it, you'll probably want to take the time to put together a voice guide. Otherwise, AI will produce AI-sounding prose by default because it has no evidence of how you actually write.
Build a voice guide once — a document that captures your actual vocabulary, your structural habits, and your writing pattens— and load it into every Claude conversation where you need to write. Claude will learn your patterns, and you'll stop re-explaining yourself every time. This guide shows you how to build that document, refine it so it's actually accurate, and save it so it's always available.
To understand your voice, Claude needs evidence. The more examples you give it, the more accurate the guide it produces. Aim for 8–10 pieces of your writing across different contexts. Don't just pull your best work — pull writing that represents how you actually communicate day-to-day.
Good sources to pull from:
- Professional emails you sent and thought landed well
- Proposals, memos, or internal documents
- LinkedIn posts, newsletters, or any public writing
- Anything you wrote quickly and didn't over-edit (these tend to reveal your natural rhythm most clearly)
Variety is helpful here. Your LinkedIn post and your emails to clients probably have different levels of formality but the same underlying voice. Giving Claude both shows it the constant underneath the variables. You don't need to paste 30 pages of documents — 500–1,000 words per example is enough for Claude to identify patterns.
Tip
Include at least one piece you're genuinely proud of and one you dashed off quickly. The proud piece shows your aspirational voice; the quick one shows how you write when you're not thinking about it.
Paste all your examples into a single Claude message, with this prompt at the end:
Paste this into Claude
"Here are [X] examples of my writing. Analyze them and create a voice guide I can use to instruct Claude to write in my voice. Focus on: the vocabulary I use naturally, my sentence structure and rhythm, how I organize and format information, and the words, phrases, and sentence patterns I should avoid because they'd sound out of character. Also flag any patterns that read as AI-generated that I should explicitly ban. Save this as a document called [Your Name] Voice Guide."
When Claude produces the guide, copy the full text and save it somewhere you can find it — a Notion page, a Google Doc, or a text file works fine. Don't close the chat first. If you've already set up your Personal AI Operating System, this is a good file to add to your Operating Context folder.
Claude will read across all your examples and produce a guide covering your vocabulary, structural habits, voice signatures, and an avoidance list. That last section is often the most useful part — Claude is good at identifying the AI-sounding patterns that tend to creep into AI-assisted writing precisely because it knows what those patterns are.
Example
You paste in six longer work emails, three internal memos, and two LinkedIn posts. Claude produces a guide that identifies your habit of opening every paragraph with a direct claim, your preference for em dashes as mid-sentence asides rather than dramatic pivots, a vocabulary list of words you naturally write with, and a list of patterns you never use — emojis, multiple exclamation points, etc. You now have a reference document that took 10 minutes to produce and will save editing time on every piece of AI-assisted writing going forward.
Read the guide carefully. Claude's analysis is usually accurate on structure and vocabulary — it's good at spotting patterns across a body of writing. Where it tends to miss: anything about why you write the way you do, and how your register shifts across different contexts.
Two questions to ask yourself:
- What did it get right that you wouldn't have thought to say? These are often the most valuable entries — patterns so natural to you that you've never had to articulate them.
- What did it overstate or get wrong? Edit those entries directly.
Then pressure-test it: ask Claude to write one short paragraph in your voice on a topic you'd actually write about, then read it. If something feels off, trace it back to the guide and fix the relevant rule. Add anything it missed: specific topics you cover often, audiences where your register shifts, domain-specific vocabulary that's part of your professional identity.
Tip
Save the guide somewhere you can actually find it — a Notion page, a Google Doc, a text file. The point is that it lives in one accessible place, not buried in a conversation you'll never locate again.
Three ways to deploy your voice guide, in order of how much setup they require:
Paste it into the conversation. At the start of any chat where you're writing, paste the guide and say: "Read this first. Everything you write in this conversation should match this voice." This requires the least up front setup, but means you have to copy and paste for every conversation, so I don't recommend it.
Load it into a Claude "Writing" Project. Projects are persistent workspaces in Claude — find them by clicking "New Project" in the left sidebar of Claude.ai. Each Project has its own instructions that load automatically for every conversation inside it. Create a Project for your writing work, paste the voice guide into the Project Instructions, and every conversation inside that Project automatically inherits your voice.
Save it in a connected folder. If you use Claude Cowork with a connected folder on your computer, drop the guide into your Operating Context folder and reference it in your global instructions: "Always read [Voice Guide filename] before writing anything in my voice." Cowork will read it automatically.
Example
You create a "Writing" project in Claude and paste your voice guide into the project instructions. The next time you need to draft a client proposal, you open that project, describe what you need, and the draft comes back with your sentence rhythms, vocabulary, and structural habits already in place.
Your voice stays constant across channels, but the tone, level of professionalism, and format rules change. A Slack message to a colleague and a client proposal are both recognizably you — but one has incomplete sentences, no capitalization, and zero headers; the other has clear structure and a professional sign-off. Once your core guide is solid, ask Claude to build three shorter channel-specific versions:
Paste this into Claude
"Based on my voice guide, create three brief channel-specific adaptations: one for professional email, one for Slack messages, and one for longer-form writing such as proposals, reports, and LinkedIn posts. Keep the core voice constant — same vocabulary, same patterns to avoid — but adjust the format rules, length expectations, and register for each channel."
What each one covers:
- Email: directness, subject line approach, when headers are appropriate versus prose, sign-off style
- Slack: conversational shortcuts, acceptable informality, emoji use, when bullets help versus when they're overkill
- Long-form: how to open a piece, argument flow, when to use headers, appropriate length and depth
Add these as sub-sections of your main voice guide or as separate files. Reference whichever applies depending on what you're drafting.
Example
Your email adaptation specifies: lead with the ask in the first sentence, keep it under 150 words unless the situation genuinely requires more, no sign-off filler. Your Slack adaptation says: incomplete sentences are fine, use bullets only for actual lists, match the informality of whoever you're writing to, 1-2 emojis per message are fine. Your long-form adaptation covers structure: claim first, evidence after, one idea per section, no summary sentence at the end of each section. Three files, all drawing from the same core voice.
Tip
If you write to distinctly different audiences — internal colleagues versus clients, or technical versus non-technical readers — add a brief note in each channel guide about how your tone shifts, even when the underlying voice stays the same.
You've built a voice guide. Here's what you now have.
- A reusable document that captures your vocabulary, sentence structure, and patterns to avoid — derived from your actual writing, not from instructions you made up
- Channel-specific adaptations for email, Slack, and long-form content
- A system for loading your voice into any Claude conversation automatically
Step 2 takes about 10 minutes once your examples are ready. Gathering the examples in Step 1 may take another 15–20 minutes, depending on how scattered your writing lives. After that, it works on every piece of writing you use it for. I revisit mine every few months, or whenever I notice the drafts starting to drift.
Try it this week
Gather five to eight pieces of your writing from the last month and paste them into Claude with the derivation prompt from Step 2. Even if you don't do anything else from this guide, reading how Claude characterizes your voice will tell you something about how you write that you probably haven't explicitly thought about.