Marcus sent me a Slack message on Tuesday. He’d pasted 15 of his own emails into Claude, typed “write like me,” and got back something that opened with: “I hope this email finds you well.”
He has never written that phrase in his life. He actually winced reading it back.
The model wasn’t the problem. The instruction was. “Write like me” is a wish, not a constraint. And AI doesn’t grant wishes; it follows rules. A developer on Reddit just shared the framework that finally makes voice cloning actually work, and it’s worth five minutes.
🔍 Why the usual approach falls apart
When you paste sample emails and say “match my style,” the AI picks up surface patterns. Average sentence length. Whether you open with “hi” or “hello.” Maybe it notices you never use exclamation marks.
What it completely misses is your structural DNA: how you open an argument, whether you hedge or just state things, where the main point lands in a message. Someone who always buries the ask in paragraph three sounds nothing like someone who leads with it, even if both write short sentences.
That gap is why AI output sounds like a polished stranger wrote it. Technically close. Emotionally off. The vocabulary might be yours; the rhythm never is. It’s like getting a cover band that knows the chords but plays at the wrong tempo.
🛠 The 6-dimension Communication Profile
The framework comes from u/blobxiaoyao on r/PromptEngineering. Core idea: stop describing your style with vague adjectives and start treating it like a config file.
Six dimensions to define:
- Sentence cadence: Short punchy lines or long compound ones? Intentional fragments? Do you vary the rhythm deliberately or keep it consistent?
- Greetings and sign-offs: The exact wording matters. “Hi Sarah,” reads completely different from “Sarah,” which reads completely different from “Hey.” Same logic applies to how you close: “thanks” vs. “cheers” vs. nothing at all.
- Vocabulary: Signature words, contractions, jargon you lean on, and words you’d never use. If you always say “solid” instead of “good” and “loop you in” instead of “CC you,” that belongs in here.
- Grammar and formatting: Oxford comma, paragraph length, how and when you use bullet points
- Formality level: “Professional-warm” vs. “formal-transactional” vs. “casual friend”
- Persuasion style: Do you lead with the ask or build context first?
Then you run 10-15 of your raw emails through this extraction prompt:
Analyze the raw writing samples below across these dimensions: 1. Sentence Cadence and Structure. 2. Greetings and Sign-offs. 3. Vocabulary Preferences. 4. Grammar and Formatting. 5. Formality and Distance. 6. Persuasion and Rhetoric. Output a structured document labeled “COMMUNICATION PROFILE” detailed enough that another AI model could reproduce the writing style using only this document.
=== WRITING SAMPLES ===
[Insert 10-15 raw emails or messages here]
Claude tends to pull the most granular profiles because of its long-context understanding, but GPT-4o and Gemini work fine too.
💡 The step most people skip
A profile tells the AI what to do. You also need to tell it what not to do.
Add an explicit blocklist to your Communication Profile. Banned phrases should include:
- “I hope this email finds you well”
- “I wanted to reach out”
- “Please don’t hesitate to”
- Any sentence starting with “I just wanted to…”
- “Circling back” and “touching base” if you’re someone who just says “following up”
If you don’t write three-paragraph emails with a pleasantry sandwich at the start and end, forbid that structure outright. AI defaults to what’s statistically common across the internet, not to what’s actually yours. The blocklist is how you draw a hard line between “internet average” and “specifically me.”
One more thing worth adding: a self-correction loop. After the AI drafts something, tell it to review the output against your Communication Profile and rewrite anything that sounds generic. The original author says this catches roughly 60-70% of remaining AI-isms. Takes about 10 extra seconds. Read the rewrite out loud if you’re still unsure. You’ll hear the off notes faster than you’ll see them.
For keeping the profile active across sessions, upload it to Claude Projects or a custom GPT. Or embed it in your API system prompt if you’re building automations. Set it once, forget it.
🚀 Try it this week
Grab 10-15 of your actual emails. Not the polished ones. The quick ones, the lazy ones you sent in three minutes between meetings. Those are your real voice.
Run them through the extraction prompt. Save the output as a markdown file. Drop it at the top of every writing prompt from now on. Revisit it every few months since your voice shifts over time, especially if your role or audience changes.
If AI copy has been frustrating you because it’s “close but wrong,” now you know exactly why. And now you have the fix.
Frequently Asked Questions
Q: How do I use negative constraints to stop my AI drafts from sounding generic?
Most people focus on what the AI should do, but forget the DON’Ts. Add 3, 5 negative examples (snippets of AI-generated text you’d never write) and a “do not use” phrase list to your Communication Profile. Doing this catches about 90% of canned, corporate-sounding lines.
Q: Does pasting my Communication Profile into every prompt waste token limits?
It can. A full profile prepended to every message adds up, especially in long sessions. Load it on demand instead, or paste it only when iterating on major drafts. If you’re tracking weekly token usage, this choice matters.
Q: Can I reuse my Communication Profile across projects?
Yes. Store your voice constraints in a system doc alongside your workflows and treat voice as a reusable asset. This beats rewriting your profile each time, just pull it into whatever project needs consistency.
Q: What does an actual extracted Communication Profile look like?
It includes specifics: sentence cadence patterns (e.g., alternating short 3, 5 word sentences with longer compound ones), exact greeting styles (“Sarah , ” vs. formal openers), signature vocabulary you lean on, and what you actively avoid. Keeping this level of detail in a “prompt vault” and pasting it when starting new drafts is what stops outputs from sounding like a template.
A 6-Dimension Framework and Extraction Prompt to Clone Your Writing Voice in LLMs
by u/blobxiaoyao in PromptEngineering