A prompt is the input you give a language model (an LLM) to get the output you want. The model is fixed. The prompt is the one part of the exchange you control, which makes it the main lever you have over the quality of what comes back.
What makes a good prompt? Four ingredients
Treat it as a brief for a freelancer. “Design a logo for my company” gets you a freelancer coming straight back at you: what is your style, what does your brand sound like. Go back and forth like that a few times and both sides are frustrated. ChatGPT is the same freelancer with one difference. It never gets annoyed with you, and it never asks. It fills the gaps in your brief itself, picks the most average answer available for each one, and hands you something generic.
Filling those gaps yourself, on purpose, is what people mean by prompt engineering. It is four things.
- Context. Almost everyone does this part and almost everyone stops early. “I run a solar company” is a category, not a brief.
- Specifics. Who this is about, what it is, and when it is happening. A model cannot guess that the email goes to the landlord rather than the tenant, or that the install is Thursday.
- An example. A piece of copy you have written before and liked. One approved example tells a model more about your voice than a paragraph describing your voice.
- Constraints. “Keep this under 100 words.” “Keep it friendly.” They take one line each and rule out whole categories of wrong answer.
Iterating on the prompt is the fifth ingredient, if you want to count it. The first brief is rarely the right one.
Put together, the logo request stops being one line. We are a residential solar installer, our branding is navy and modern, here is the logo we use today, and here is specifically what I need. Same request. Answerable on the first attempt.
Why are ChatGPT’s answers so generic?
Because most people type into it the way they type into a search box, out of muscle memory. Ask Google for the best running shoes in 2026 and it matches keywords across an enormous database of pages, then returns one conclusive answer: the same answer it gives everybody else who asks.
Now ask ChatGPT or Claude this instead. I am flatfooted, I weigh 200 lb, and I am looking for a daily trainer. Three facts, and the reply stops being a list of popular shoes. That is the job a search engine handles badly and a model handles well, because it works through the options against your situation rather than ranking pages.
Your own work has the same shape. “Write a follow-up email to a customer” produces a template you would not send. “Write a follow-up to a homeowner who got a heat pump quote last Tuesday and has not called back, under 100 words, friendly, no discount” produces something you can send as written. The second prompt is longer by one sentence, and everything in that sentence is something you already knew before you opened the chat.
Both examples side by side:
| Bad prompt | Good prompt | What changed |
|---|---|---|
| Design a logo for my company | We are a residential solar installer, our branding is navy and modern, here is the logo we use today, and here is what I need | Who you are, and what you already have |
| Write a follow-up email to a customer | Write a follow-up to a homeowner who got a heat pump quote last Tuesday and has not called back, under 100 words, friendly, no discount | Who it goes to, when it happened, and the limits on it |
When should you start a new chat?
One of the first things we see when we start consulting with a business is people trying to correct course in the middle of a session. The answers drift, so they add a correction, then another, and now half the chat is bad instructions the model is still reading.
Clear it. Pull the useful pieces out of that conversation, fold them into one new prompt, and start again. The corrections you typed all afternoon are the brief you should have opened with.
A long session drifts because of the context window: the whole chat, your wrong turns included, gets read again on every message you send. That is the next lesson, along with the tokens the window is measured in.