Course A · Module A2 Prompting · Lesson 5 of 17
Stop rewriting the same prompt from memory. Save it once as a template, and every future run takes thirty seconds.
You've already written a prompt that works. The problem is you'll write it differently next time — slightly shorter, a different instruction — and get a worse result. A prompt library solves that: you store the prompt that worked, mark the parts that change each time with [BRACKETS], and paste it forever. That's the single win from this lesson: one recurring task turns into a fill-in-the-blank template you never rebuild from scratch.
Think of a great recipe card. You don't rethink the whole dish each time — you follow the same card and swap the variable ingredient for what's in season. A prompt template works exactly the same way: the fixed instructions stay in the card; only the [BRACKETED] slot changes per run.
Bonus: when a template stops working, you edit one place. Every future run improves instantly — no hunting through chat history to remember how you phrased it.
Write your best prompt once. Then look at every word that changes from one use to the
next — a client name, a topic, a date, a tone — and wrap it in [BRACKETS].
Those become your fill-in slots. Everything outside the brackets is locked, tested
instruction text.
# Template: Weekly project-status email You are a clear, professional assistant. Write a brief status email for a client. Project: [PROJECT NAME] This week: [2–3 bullet points of what was completed] Next week: [1–2 planned steps] Blockers: [any issues, or "none"] Tone: [professional / warm / brief] Keep it under 150 words. Use the client's first name: [CLIENT FIRST NAME].
Every [BRACKET] is a decision made once. The surrounding
instructions — word count, tone, structure — never change. That's what makes the
output consistent.
Go back to the automation task you chose in Lesson 3. Write your best current prompt for it. Then do three things:
[DESCRIPTIVE LABEL].Answer before opening. Recalling it now is what makes it stick.
The parts that change each time. Brackets mark the variable slots — a client name, a topic, a date — so the stable instruction text around them never needs rewriting.
You didn't save the exact prompt. Small wording changes produce different outputs. The fix: copy the winning prompt straight into your library doc before closing the chat.
Add more specific context slots. Bracket out things like [ONE SPECIFIC REASON WE'RE REACHING OUT] and [RECIPIENT'S INDUSTRY] so you're forced to supply the details that make output feel personal. Generic prompt in, generic output out.
Read this next (primary source)
Prompt Engineering Overview — Anthropic. The canonical reference for writing reliable, reusable prompts. Section on "be clear and direct" maps directly to the bracket-method above. ~10 min. See RESOURCES.md for more.
New words this lesson — prompt, context, token — are defined in the course glossary. Keep it open.