Prompt Engineering
E-commerce Prompt Library
A documented prompt system for product descriptions, email sequences and ad copy, with A/B tested variants.
- Client
- E-commerce brand
- Year
- 2026
- Services
- Prompt Engineering
200+Prompts delivered
60% fasterContent production
Consistent across channelsBrand voice
Figures as reported by the client at the end of the engagement. Hirelyx has not independently audited them.
The challenge
What was actually wrong
Content was being generated ad hoc by several people, each with their own prompts, so brand voice drifted between a product page and an email.
There was no way to tell whether a prompt change made output better or merely different.
The solution
What we built
A versioned prompt library organised by use case, with a shared system prompt carrying brand voice and constraints, and per-task prompts layered on top.
An evaluation set drawn from real briefs, with grading criteria, so each change could be measured rather than argued about.
Implementation
How the work was carried out
The sequence that mattered, including the decisions that prevented later rework.
Technology stack
- Anthropic Claude
- OpenAI GPT
- Structured output
- A/B testing
- 01
Voice specification
Brand voice written down as explicit constraints instead of adjectives, so a model could follow it.
- 02
Use-case decomposition
Product copy, email and ad copy treated as separate tasks with separate output contracts.
- 03
Graded iteration
Variants scored against the evaluation set; only measured improvements were kept.
- 04
Handover
Library, grading harness and a change process documented for the brand's own team.
Outcome
The team now produces on-brand copy from a shared library, and can tell whether a change to it actually helped.
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Want something like this for your business?
Tell us where you are now. You will get a written scope, a fixed quote and an honest answer about whether this is the right next step.
- A written scope and fixed quote before work starts
- Payments handled securely through Stripe
- Code, accounts and documentation stay yours
- Typical first reply within 24–48 hours