Claude prompt engineering basics — write prompts that actually work
Prompt engineering sounds like a job title someone invented to sell a course. It's actually just learning to ask properly. Here are the basics that cover 90% of everyday use.
What prompt engineering actually is
Claude is not a mind reader. When you type "write me an email," it has to guess who the email is for, what it's about, how formal it should be, and how long. It guesses reasonably — and you get a reasonable, generic email that sounds like nobody.
Prompt engineering is the unglamorous fix: you stop making Claude guess. You tell it what you'd tell a competent colleague who just started today. That's the whole discipline. Everything else is refinement.
If you're brand new to Claude, do the getting started lesson first — this one builds directly on it.
The four parts of a good prompt
Nearly every strong prompt contains the same four ingredients. Miss one and the output gets noticeably worse.
| Part | What it does | Example |
|---|---|---|
| Role / context | Tells Claude who's asking and what the situation is | "I'm a special education teacher writing to a parent." |
| Task | The one specific thing you want done | "Draft an email about their son's progress this term." |
| Constraints | The boundaries: tone, length, what to avoid | "Warm but professional. Max 6 sentences. No jargon." |
| Format | What the output should look like | "Give me a subject line plus the email body." |
You don't need to label the parts. You just need all four to be in there, in plain language.
A template you can steal
Copy this, fill in the brackets, delete what you don't need:
I'm [who you are and the situation].
I need you to [one specific task].
Tone: [warm / formal / direct]. Length: [max X sentences / words].
Avoid: [anything it tends to get wrong].
Format the answer as [email / table / bullet list / plain paragraph].
If anything is unclear, ask me before answering.That last line is the one nobody uses. It stops Claude from confidently answering the wrong question — which is the single most common way beginners waste time.
Before and after
Before: write a text for my plant sale
You'll get something that reads like a supermarket flyer. Technically correct, sounds like nothing.
After: I run a small nursery selling rare edible perennials. Write a short Finn.no listing for a Schisandra chinensis plant: Latin name, Norwegian common name, one honest sentence about what it does, fair price of 150 kr. Plain language, no marketing fluff.
Same tool, same day, wildly different output. The difference wasn't a magic phrase. It was context, task, constraints, and format — all four parts, stated plainly.
Ask it to think
For anything with reasoning in it — planning, comparing options, checking numbers — add one line:
Think through this step by step before you answer, and show me your reasoning.The quality jump is real. Claude slows down, works through the problem, and you can see where it went wrong if it did — instead of just getting a wrong answer with a confident face.
Five beginner mistakes
- The one-line prompt. "Summarize this" works. "Summarize this in 3 bullets for someone who hasn't read it" works much better.
- Stacking five tasks in one prompt. Claude will do all five, each a bit worse. One task per prompt, then follow up.
- No length limit. If you don't cap it, you get an essay. Say "max 100 words" and mean it.
- Hunting for magic words. There's no secret incantation. Clear beats clever, every time.
- Repeating yourself in every chat. If you paste the same background info daily, that's not a prompting problem — see below.
When a prompt isn't enough
Prompts are for one-off instructions. The moment you notice you're typing the same context again and again — your role, your standards, your formatting preferences — move it somewhere permanent:
- Projects hold the background context, so every new chat starts pre-briefed.
- Skills hold the reusable instructions, so Claude loads your rules automatically when the task fits.
Good prompting plus a well-set-up Project is honestly most of what "AI power users" are doing. It's not more complicated than that.
What's next
Take the template above and use it three times this week on real work — an email, a summary, a plan. By the third one it stops feeling like a template and starts feeling like how you talk to Claude.