Case Study: Alex's Style Cloner — Few-Shot Prompting for Brand Voice

The Brand Voice Problem

Brightleaf Consumer Goods makes sustainable everyday products — reusable bags, bamboo kitchenware, plant-based cleaning supplies. The company's identity is built around a specific feeling: the products should feel like a small upgrade to daily life that also happens to be good for the planet. Not preachy. Not technical. Warm, practical, and a little playful.

Alex has been the marketing manager for two and a half years. In that time she has written, edited, or approved probably a thousand pieces of copy across product pages, email campaigns, social media, and packaging. She has a strong intuitive sense of the brand voice. She can read a piece of copy and know in seconds whether it sounds like Brightleaf.

When AI tools became available for marketing use, Alex was enthusiastic. The potential for speed was obvious — she needed roughly 40 new pieces of copy per month across various formats. If AI could draft them reliably, she could shift her time from writing to strategy and oversight.

The early results were discouraging.

The Adjective Problem

Alex's first approach was description. She wrote out the brand voice in her prompts:

"Write in Brightleaf's brand voice: warm, conversational, optimistic, sustainable-focused, not preachy, relatable, practical, lifestyle-oriented."

The AI produced copy that was technically aligned with those adjectives. It was warm. It was conversational. It was optimistic and practical. But it didn't sound like Brightleaf. It sounded like a hundred other lifestyle brands using the same adjectives to describe themselves.

The problem is that "warm and conversational" is a genre, not a voice. Plenty of brands are warm and conversational. What makes Brightleaf distinctive is the specific way it implements those qualities: the particular rhythm of its sentences, the way it addresses the reader directly without being cloying, the specific vocabulary register (never "eco-warrior," never "sustainably sourced," never "future generations"), the light humor that appears in specific places, the way it closes copy on a note of everyday delight rather than a call to virtue.

None of that can be captured in a list of adjectives. And Alex spent three months trying.

Her revision rate for AI-generated copy during this period was approximately 65%. The AI could produce a drafts — they just needed substantial editing to sound right.

The Five-Example Library

The shift came after a conversation with a colleague who used AI for legal document drafting. His approach: instead of describing what he wanted, he showed it. Three examples, every time.

Alex spent two hours building her example library. She went back through Brightleaf's copy archive and pulled her best work — pieces that had passed internal brand review without revisions, performed well in A/B tests, or received explicit positive feedback from the product team.

She collected ten candidates. Then she selected five, deliberately choosing pieces that represented: 1. Different product types (cleaning supply, kitchen product, personal care item) 2. Different copy formats (product page description, email subject line and header, social media caption) 3. Different "challenges" — one piece that had been praised for handling an eco claim without preachiness, one that used humor effectively, one that described a mundane product (a sponge) in a way that felt genuinely appealing

These became her brand voice reference section — a permanent fixture at the top of every copy prompt.

The Five Examples

Here are the examples Alex selected (slightly simplified for clarity):

Example 1 — Product Page Description (Bamboo cutting board):

Input: Product page description for a bamboo cutting board

Output: "Your kitchen's hardest worker, quietly doing its thing since day one. This cutting board is bamboo — which means it's gentler on knife edges, naturally antimicrobial, and has been growing without pesticides since long before anyone was paying attention. One side for produce, one side for meat. Both sides for the satisfaction of a kitchen that works without trying too hard."

Example 2 — Email Campaign Header (Reusable produce bags):

Input: Email campaign opener for reusable produce bags launch

Output: "We have a theory: the best swaps are the ones you barely notice. Switch from plastic produce bags to these mesh ones, and the weekly shop feels about the same. Except you've cut out maybe 500 bags a year, and the broccoli gets to breathe. Small move. Actually matters."

Example 3 — Social Media Caption (Dish soap):

Input: Instagram caption for concentrated plant-based dish soap refill

Output: "One bottle. Six refills. Math that makes sense. Our concentrated dish soap refill makes 6 full bottles from a single small container — which is 6 fewer plastic bottles in the world and one less thing taking up space under your sink. It cuts grease like it means it. Your dishes won't notice the difference. Your recycling bin will."

Example 4 — Product Page Description (Beeswax food wraps):

Input: Product page description for beeswax food wraps

Output: "Plastic wrap's better-looking cousin, who actually does the job. These beeswax wraps mold to your bowls, seal around leftovers, and keep cheese (finally) from drying out in the fridge. Wash with cool water, air dry, use again. They last about a year of regular use. After that, they compost. You know what doesn't? The other kind."

Example 5 — Email Subject Line + Preview Text (Sale campaign):

Input: Email subject line and preview for an end-of-year sale

Subject: "The kind of sale you tell your group chat about" Preview text: "30% off everything. Yes, including the thing you've been eyeing."

How She Structured the Prompt

Alex's final template:

Write [copy type] for [product name] — [1-2 sentence brief on the product].

Use Brightleaf's brand voice. Match the energy, rhythm, and style in
the reference examples below.

BRIGHTLEAF VOICE REFERENCE:

---
[Input: Product page description for bamboo cutting board]
[Output: "Your kitchen's hardest worker..." (full Example 1)]

---
[Input: Email campaign opener for reusable produce bags]
[Output: "We have a theory..." (full Example 2)]

---
[Input: Instagram caption for concentrated dish soap]
[Output: "One bottle..." (full Example 3)]

---
[Input: Product page description for beeswax food wraps]
[Output: "Plastic wrap's better-looking cousin..." (full Example 4)]

---
[Input: Email subject + preview for year-end sale]
[Output: Subject line and preview text (Example 5)]

---

NEW REQUEST:
[Input: specific copy request with product details]
[Output:]

The bracket format allows her to swap in any copy request while keeping the five examples constant.

The Results

The difference was visible immediately. The first piece of copy produced with the five-example prompt — a product page description for a new stainless steel food container — required zero revisions before publication. The brand team approved it on first pass, with one member noting that it "finally sounds like us."

Over the following month, Alex tracked her revision rate for AI-generated copy:

The 12% revision rate meant that approximately 1 in 8 pieces needed meaningful editing. The others were approved with minor tweaks or no changes. At 40 pieces per month, that represented roughly 20+ hours per month of editing time recovered.

Why She Chose These Five Examples

Looking back at her selection, Alex can articulate why each example earns its place:

Example 1 (cutting board) demonstrates the core structural pattern: start with a relatable observation, give the key facts in Brightleaf's specific matter-of-fact way, end with a small moment of delight. This is the backbone of most product descriptions.

Example 2 (produce bags) shows how to handle an eco-claim without preaching. The line "which is 6 fewer plastic bottles in the world" is stated as a fact, not a moral argument. This is one of Brightleaf's hardest tonal challenges to capture, and showing it in an example is the only reliable way to convey it.

Example 3 (dish soap) demonstrates the use of short punchy sentences as punctuation — "Math that makes sense." and "Your dishes won't notice the difference. Your recycling bin will." These are signature Brightleaf moves.

Example 4 (beeswax wraps) shows humor deployed without undermining the product. "Plastic wrap's better-looking cousin, who actually does the job" is funny. It's also specific, not generic.

Example 5 (sale email) is included because promotional copy has a different energy than product descriptions, and she needed to show that Brightleaf's voice holds even in a sales context. "The kind of sale you tell your group chat about" sounds like a person, not a brand announcement.

What She Learned

The key insight Alex documented for her team:

"Describing a voice and demonstrating a voice are completely different things. I can tell AI to be 'warm and conversational' all day and get generic lifestyle brand copy. Or I can show it three sentences that are warm and conversational in the specific Brightleaf way, and it gets it right. The voice lives in the specific choices — which words, which rhythm, where the humor goes, what you never say — and those specifics don't transfer through adjectives."

She also learned something about example maintenance. After six months, she noticed slight drift in the AI's output — the copy was still good, but it had started borrowing some phrases too literally from her examples (a risk of few-shot prompting when examples are used repeatedly). She refreshed two of the five examples with newer pieces, and the freshness of the output improved.

Her current practice: review the five-example library every quarter. Retire any example that's showing up too literally in outputs. Replace it with a piece that represents any new aspects of the brand that have evolved.

The Team Application

Alex's approach has since been adopted more broadly. The brand team now maintains an official "voice reference library" with 12-15 examples organized by copy type (product description, email, social, packaging). Any team member or agency working on Brightleaf copy uses the relevant subset of 3-5 examples from this library in their AI prompts.

The library is version-controlled — when the brand voice evolves, the examples are updated, and the change is documented so everyone is working from the same reference set.

"The few-shot library is essentially a living brand guide," Alex notes. "Except unlike a traditional brand guide, it shows rather than tells. Anyone can use it, not just people who've been immersed in the brand for years."