How to write with AI: emails, texts and documents that sound like you
A practical method for drafting with ChatGPT, Gemini or Claude without it sounding machine-written: context, tone, draft and review, with ready-to-copy prompts.
What it’s good for (and what it isn’t)
An assistant such as ChatGPT, Gemini or Claude is great at beating the blank page: it turns notes into an email, organises ideas, suggests three versions of a headline or changes the tone of a text. What it can’t do is know what you know: your situation, your data and the way you talk. You fill that gap with context.
The method in 4 pieces
Google’s official prompting guide for Gemini organises its examples by role and task. We sum it up in four pieces that work in any assistant:
- Who and for whom. “I’m writing as the chair of a residents’ association to all members.”
- Goal. “That they confirm attendance before Friday.”
- Format and limits. “A 120-word email with a subject line and three bullet points.”
- Tone. “Friendly, plain English, no grandiose words.”
If a piece is missing, add at the end: “If you’re missing information, ask me before writing.” It’s one of the tricks that improves results the most.
Iterate: the second message is the good one
The first answer is a draft. Ask for specific changes:
- “Make it 30% shorter.”
- “Remove the adjectives and stock phrases.”
- “Give me three different subject lines: one direct, one with a question and one with a date.”
- “Rewrite the second paragraph for someone who doesn’t know the topic.”
Make it sound like you
Paste an old text of yours (no personal data) and ask: “Imitate this style: sentence length, vocabulary and the way I sign off.” Then read the result aloud and change anything you’d never say.
What you shouldn’t delegate
- Facts, figures and quotes. AI can invent them (hallucination). Check them.
- Third-party information. Don’t paste emails with names, phone numbers or addresses. See what data never to paste.
- Texts with legal, medical or financial effects. Use it to write clearly, but the decision and the technical content must come from a professional.
Quick templates
- A polite “no”: “Help me decline [proposal] politely, thanking them for their interest and leaving the door open. 80 words.”
- Simplify: “Rewrite this text so anyone can understand it, with short sentences and no jargon: [text].”
- Correct without rewriting: “Fix only spelling and grammar. Don’t change the style. Show the changes in bold.”
Frequently asked questions
Can people tell a text was written with AI?
Often, yes: generic phrases, too many adjectives and repetitive structure. You reduce this by giving context, asking for a specific tone, providing a sample of your style and editing the final version.
Can I paste an email I received so it helps me reply?
Only if you first remove names, addresses, phone numbers and any third-party data. Read our guide on what data never to paste.
Which assistant writes best?
ChatGPT, Gemini and Claude all write well. The differences depend more on how you ask than on the tool. Try the same prompt in two and keep whichever works best for you.
Keep reading
Sources
- Prompting guide 101 (Google Workspace con Gemini) — Google
- GPT-6 and Intelligent UI for everyone — OpenAI
- Planes y precios de Claude — Anthropic
- Guías de la AEPD — Agencia Española de Protección de Datos
Change log
- : First published.
Educational content, prepared with the help of AI tools, with sources cited. It is not a substitute for professional advice. Tools change fast: if you spot something out of date, write to us at contacto@cognenza.com. How we work.