The Complete Guide to AI Tone and Formality

Why Tone Matters

You wouldn't write an email to your CEO the same way you'd message a teammate on Slack. Yet default AI outputs often sound the same regardless of context.

Getting tone right is one of the most impactful things you can do with custom instructions. Here's how to think about it.

The Formality Spectrum

Think of formality on a 1-5 scale:

Level 1 - Very Casual: Slack messages to close colleagues, internal team chat

Level 2 - Casual Professional: Emails to teammates, LinkedIn posts

Level 3 - Professional: Client communications, external emails

Level 4 - Formal: Executive communications, official documents

Level 5 - Very Formal: Legal documents, board presentations

Most professionals operate primarily at levels 2-4, but context matters.

Defining Your Default

Your custom instructions should set a default tone that matches your most common use case. Then you can adjust per-request when needed.

Example: "Default to a professional but warm tone (formality level 3/5). Be direct without being curt. Use conversational language while maintaining professionalism."

Tone Components

Tone is more than just formal vs. casual. Consider these dimensions:

Confidence level: Assertive vs. hedging

Detail orientation: Concise vs. thorough

Warmth: Friendly vs. neutral

Energy: Enthusiastic vs. measured

Structure: Organized vs. flowing

Instructions by Context

Here's how to specify tone for different situations:

Executive communications:

"Be concise and direct. Lead with the bottom line. Use clear, confident language. Avoid unnecessary qualifiers."

Client-facing:

"Maintain a warm, professional tone. Be helpful and thorough without being verbose. Always end with a clear next step."

Team collaboration:

"Be casual but clear. It's okay to be brief. Use a conversational style."

Thought leadership:

"Be authoritative but accessible. Use confident language. Support points with specific examples or data."

Common Tone Problems

❌ **Over-hedging:** "It might perhaps be possible that..." → Just state your point directly

❌ **False enthusiasm:** "I'm SO excited to..." → Genuine warmth doesn't need exclamation points

❌ **Robot voice:** Overly formal language that sounds unnatural → Write like you talk (professionally)

❌ **Inconsistency:** Mixing very formal and very casual in the same piece → Pick a lane

Making It Work Across Platforms

The same tone instructions work across ChatGPT, Claude, Copilot, and Gemini. Each platform will interpret them slightly differently, but your core voice will come through.

Your Turn

Generate your ProPrompt and we'll help you define the perfect default tone based on your role, industry, and communication preferences.