Reusable AI Prompt Templates: Variables, Versions, and Side-by-Side Tests

Key takeaway & what you'll build

A prompt template keeps the parts that never change and marks the parts that do with clear placeholders, such as [AUDIENCE] or [ARTICLE TEXT]. Keep a version note when you change a template, and compare two versions on the same input before you switch. Save templates in your Library so they're one click from Ask Ace.

You'll build: Your own prompt library

Stop retyping your best prompts

If you've written a prompt that works, you'll want it again next week. A template keeps everything that stays the same and marks what changes.

Anatomy of a template

You are an editor for [PUBLICATION], writing for [AUDIENCE].

Summarize the article below in [NUMBER] bullet points, each under 20 words.
Lead with the most surprising finding. Don't add facts that aren't in the article.

Article:
[ARTICLE TEXT]

Fixed parts: the role pattern, the task, the rules, and the format.
Placeholders: clear, capitalised, in square brackets, so you can't miss one.
The input slot at the end, where long material goes.

Naming and organising

A library is only useful if you can find things in it. Name each saved prompt by task and audience: "Article summary — busy executives" beats "summary prompt v3." Keep one prompt per job; a mega-prompt that does everything usually does nothing well.

Versions

When you improve a template, keep a short note at the top of it:

v2 (Nov): added "lead with the most surprising finding" — v1 summaries were flat.

Then you know why it changed, and you can go back if v2 turns out worse.

Side-by-side tests

Before replacing a template you trust, test the old and new versions on the same input, ideally two or three inputs. Run each in Ask Ace in its own chat, then read the outputs side by side. Same input, same model, one difference: that's a fair test. Ask Ace lets you pick the model, so keep it the same for both runs.

Using a template in Ace

Saved prompts live under Library → Saved Prompts. Click 💬 on one to open Ask Ace with the template in the message box, replace the placeholders, paste your input, and send.

Try it

Turn the prompt you built in the last lab into a template with at least two placeholders, give it a clear name, and add a version note. Then run it from Saved Prompts with a new input.