Controlling output format
Length, tone, lists vs. prose, and markdown
Format is a first-class concern
Claude will default to formats that look good in a chat interface: markdown headers, bullet lists, moderate length. These defaults are often wrong for your actual use case — you might need plain text for email, a specific word count, a formal tone, or a dense paragraph rather than a list.
The good news: Claude responds extremely well to explicit format instructions. You do not have to accept the defaults.
Length control
| What you want | How to say it |
|---|---|
| Short answer | “Answer in 2 sentences or fewer” |
| Specific length | “Write approximately 200 words” or “keep under 150 words” |
| Comprehensive | “Be thorough — this is a reference document, not a summary” |
| Variable | “Be as brief as the topic allows, but don’t truncate important detail” |
Tone control
Claude can match almost any voice. The key is being specific — “professional” means nothing without a reference point. “Professional like a McKinsey memo” and “professional like a friendly SaaS onboarding email” are completely different tones.
- Pair a descriptor with an example: “Conversational but authoritative, like how Ann Handley writes”
- Name the audience: “Write for a non-technical small business owner in their 50s”
- Use contrast: “Direct and concise — not formal, not casual, no filler phrases”
Lists vs. prose
Lists are Claude’s default because they look organized. But lists fragment information — they are great for scannable how-tos, bad for narrative analysis or persuasive writing.
Watch out: If Claude is giving you bulleted responses when you need flowing writing — add “Write in prose paragraphs, no bullet points or headers” to your prompt.
Giving Claude a template
The most powerful format control technique: give Claude a template to fill in.
Write a project kickoff email using this exact structure:
Hi [client name],
[One sentence expressing excitement about the project]
Here's what happens next:
- [Step 1 with date]
- [Step 2 with date]
[One sentence about what you need from them by when]
[Sign-off]Try it: Take a prompt you’ve used before. Add explicit format instructions: word count, tone reference, prose vs. list, and whether to use markdown. Compare the before/after output.