A reusable brand voice prompt is a short block of text with seven parts: who you are, who you write for, how you sound, what you always do, what you never say, three real examples, and the format. Paste it above every caption request and the output stops sounding like generic AI. The template, a filled-in example and a five-post test are below.
TLDR: Write the seven lines once, put three of your best real captions in the examples line, and test the prompt on five different posts before you trust it. Fix the prompt, not the captions, and keep one saved version per brand.
Mydrop data, September 2026: across accounts connected to Mydrop, which manages 55,000+ posts, captions under 80 characters ran 9% below their account's typical post. From 80 characters up, length made no measurable difference: every bucket from 80 to 600+ characters sat within 3% of the median. Method and full tables in the Mydrop social media benchmarks.
The seven-line template
Copy this and replace the brackets.
ROLE: You write social captions for [brand], which sells [what] to [who].
AUDIENCE: [One sentence: who reads this and what they care about.]
VOICE: [Three adjectives.] In practice: [one sentence on what that means.]
ALWAYS: [Three habits, e.g. open with the benefit, use one number, say "you".]
NEVER: [Banned words, claims, emojis, punctuation.]
EXAMPLES: [Paste three real captions you are proud of.]
FORMAT: [Length, hashtag rule, emoji rule, call to action rule.]
The prompt filled in for a coffee roaster
Here is the same template for a small coffee roaster.
ROLE: You write Instagram captions for Ember Coffee, which sells
small-batch beans to home brewers.
AUDIENCE: People who own a grinder and want better coffee, not a lecture.
VOICE: Warm, specific, a little dry. In practice: we talk like a barista
who likes you.
ALWAYS: Name the origin or the tasting note. Use one number. Say "you".
NEVER: "Elevate", "journey", exclamation marks, more than one emoji.
EXAMPLES: [three real captions]
FORMAT: 2 to 4 sentences, at least 80 characters, 3 hashtags at the end,
one question as the call to action.
Let the examples do the heavy lifting
"Friendly" means something different to every writer, human or AI. Three real captions show rhythm, length and word choice in a way adjectives cannot.
Pick them from your own best-performing posts: one short, one long, and one with a call to action. If you have no history yet, write three yourself and edit them until you would be proud to see them under your name.
The FORMAT line deserves a floor, not a target. In Mydrop's September 2026 data, captions under 80 characters ran 9% below the account's median, while every length from 80 characters up performed about the same. So write "at least 80 characters" and stop worrying about the rest.
Test it on five posts before you trust it
One good caption proves nothing. Run the prompt on five briefs that are different on purpose: a product launch, a behind-the-scenes post, a reply to a comment, a promotion and a piece of bad news.
Score each result from 1 to 5 on three questions:
- Would we say this out loud?
- Does it contain a banned word or habit?
- Does it say something specific that only we could say?
If the same flaw shows up twice, fix the prompt:
| Symptom | Fix in the prompt |
|---|---|
| Too salesy | Add hype words and exclamation marks to NEVER, and swap in a calmer example |
| Generic | Put real product names and numbers in ROLE |
| Too long | Set a maximum in FORMAT |
| Sounds different on each platform | Add one FORMAT line per platform |
| Repeats the same opener | Add the opener to NEVER |
Keep one version for the whole team
Prompts break when five people keep five private copies. Store the current version in one place, put a date on it, and change one line at a time so you can tell which change helped.
If you run several brands, you need one prompt per brand and no copy-pasting between chats. Mydrop's brands store the voice once (audience, tone, hashtags and do and do-not rules), and the AI content studio writes from that brand, so a new teammate does not have to re-explain it.
Next step: fill in the seven lines for one brand today and run the five-post test. When it passes, save it and start free with Mydrop to keep it next to the calendar where you use it.
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