How to write a good prompt

A prompt is simply what you type to an AI assistant. The same assistant gives a vague answer to a vague prompt and a useful answer to a clear one. Writing a clear prompt is not a technical skill. It is the same skill as briefing a new colleague who is clever, quick and knows nothing about your situation.

Think of a new colleague

Imagine handing work to someone on their first day. If you say "write to the supplier", they will ask: which supplier, about what, in what tone, how long, and what do we want from them? An assistant does not ask. It guesses, and it writes its guess confidently. A good prompt answers those questions before they arise.

The five parts

Most good prompts contain five things. You do not need headings for them, and short prompts may fold several into one sentence.

The task. What you want done, as a plain instruction. "Write", "summarise", "compare", "list", "explain", "correct".
The context. The facts the assistant cannot know: who you are, what has happened, the material to work on.
The reader. Who the result is for and what they already know.
The format. How long, and in what shape: a table, a numbered list, an email with a subject line, three versions.
The limits. What to leave out, and what not to invent.

A worked example

Here is a weak prompt:

Write a notice about the water problem.

The assistant must guess everything. It will produce a long general notice that fits no real place.

Here is the same request with the five parts:

Write a notice for the residents of our housing society.

Facts: the water tank will be cleaned on [DATE]. There will be no water supply from 10 in the morning to 4 in the afternoon. Residents should store water the evening before.

The notice will go on the notice board and in the WhatsApp group. Readers include elderly residents, so keep the language simple.

Under 80 words, with a clear heading. Give it in English and in Hindi. Do not add any detail that I have not given.

Replace the parts in [CAPITALS] first, or after pasting.

Now the task, the facts, the readers, the format and the limits are all stated, and the first answer is likely to be usable.

Small phrases that help a lot

"Use only the information I give." Reduces invented details.
"If anything important is missing, ask me before you write." Makes the assistant show what it does not know.
"Under 100 words." A number works better than "short".
"Give me three versions." Lets you choose and combine.
"Explain your choices in one line each." Helps you judge and learn.
"Do not rewrite it, only list the problems." Keeps your own work your own.
"Mark anything you are unsure of with [CHECK]." Shows you where to look.

Give an example of what you want

If you have a sample of the style you like, such as an earlier notice or a reply you were pleased with, paste it and say "write in this style". One example tells the assistant more than a paragraph of description.

Put the material in clearly

When you paste text for the assistant to work on, separate it from your instruction. Put the instruction first, then a blank line, then the text. For longer material, say what it is: "The email I received is below." This stops the assistant from confusing your words with the words to be worked on.

Do not chase the perfect prompt

There are no magic words. Promises of secret phrases that unlock better answers are mostly exaggeration. A clear first prompt followed by one or two follow-up messages beats an hour spent polishing one prompt. Send it, read the answer, and say what to change.

A short checklist

Before you press enter, ask yourself:

Have I said what I want done?
Have I given the facts it cannot know?
Have I said who it is for?
Have I said how long and in what form?
Have I said what not to invent?
Have I removed anything private?

If the answer to all six is yes, the prompt is good enough.

This is an independent site. It is not connected with any company that makes AI assistants. The prompts are plain text and can be used in any AI chat assistant. An AI assistant can give wrong or made-up answers: check anything important before you rely on it, and do not paste private details into a prompt.