Prompt Basics — Saying Exactly What You Want

1.Why do answers change depending on the question?

In Lesson 4 we saw that a language model looks at the text so far and picks the most plausible thing to come next. That makes the prompt the beginning of that "text so far." If the input is vague, the range of plausible answers is wide, and the model picks the most ordinary, safest answer. If the input is specific, the range of plausible answers narrows and gets closer to the answer you want.

It is exactly like handing work to a person. If you just tell a new coworker, "Write a report," they will not know what to write. You have to tell them who will read it, what decision it is meant to support, how long it should be and what shape it should take before you get a usable result. An AI does not even have the context to read between the lines, so you need to spell it out all the more.

2.The four elements of a good prompt

Not every prompt needs all four, but they make a good checklist for finding what is missing when you don't like an answer.

• Wrong: Make me a workout plan.Right: I'm an office worker in my 40s and want to build stamina. My knees are weak, so I'd like to avoid running. Make me a 4-week workout plan I can do at home without equipment, 20 minutes a day, 4 days a week, as a table organized by day of the week.It includes the goal (building stamina), the context (age, knees), the constraints (no equipment, 20 minutes, 4 days a week) and the format (a table by day of the week).
• Wrong: Fix this text.Right: The text below is an apology notice to customers. Don't change the content; just make it more polite and shorter. Below the revised text, explain in three lines what you changed and why.If you don't say what to change and what to keep, the AI may change the content as well.

3.Tips for being specific

Being specific does not mean writing more. It means replacing words that can be interpreted in different ways with numbers and examples. Change "short" to "in three sentences," "simple" to "so a middle school student can understand," and "a good title" to "five titles of no more than 20 characters, each containing a number," and the results change.

If you have material, paste it in. The AI has no way of knowing your company's situation or the article you read. If you provide the material to base the answer on and say "based on this material," there is less room for the AI to make things up. It is even better to mark the beginning and end of the material so it doesn't get mixed up with your instructions.

Korean Language Basics, Lesson 10, "Clear Sentences for Prompts" (a Korean-language course), practices writing sentences with a clear subject and object and avoiding vague references. In the end, much of the skill of writing good prompts is simply the skill of writing clearly in your own language.

• Replace vague adjectives (short, simple, good) with numbers or criteria
• State who will read it and where it will be used (for whom, for what)
• Also write down what not to do (no jargon, no guessing)
• Decide the shape of the result you want (table, list, number of paragraphs, length)
• Paste in supporting material, and keep the material separate from the instructions

4.Missing information is the problem, not missing magic words

You often hear that there are "secret phrases" for writing good prompts — that adding certain words or changing your tone makes the answers dramatically better. Wording can affect the result a little, but when you don't like an answer, the cause is usually not the wording but missing information that the AI has no way of knowing.

So when an answer is not what you expected, go back to the four-element checklist before changing the wording. Find which of the goal, context, constraints and format is missing and fill it in, and the result will change even if you ask in the same tone. Below is an example that walks through this process step by step.

5.Don't try to finish in one go — refine through conversation

It is normal for the first answer not to be perfect. Seeing the first answer often makes it clearer what you actually wanted. Rather than asking again from scratch, pinpoint what to fix — "more detail on the second item," "make the tone more formal," "change the order of the table's columns" — and it will improve quickly.

You can also go the other way and have the AI ask questions first. If you say, "Before doing this, first ask me what else you need to know," the AI will look for the missing information and ask about it. This is especially useful when you yourself don't know what you left out.

6.What not to put in a prompt

With an online AI service, whatever you put in a prompt is sent to the service provider's servers. Depending on the service and your settings, it may be stored or used to improve quality. So the rule is not to include national ID numbers (such as Social Security numbers), bank account or card numbers, passwords, other people's personal information or your company's confidential material.

If you really must work with real material, change names to "Person A" and company names to "Company B," and keep only as many numbers as you need. When using AI at work, first check which services and rules your company allows. We go into more detail in Lesson 8.