A prompt is a set of instructions for a model that knows only what you wrote. Most weak answers come from a prompt that left something out, not from a model that could not do the job. Four published guides, from OpenAI, Atlassian, GitHub and Anthropic, agree on the habits below.

Try the colleague test

Anthropic suggests a simple test: show your prompt to a colleague who has never seen the task and ask them to follow it. If they would be confused, the model will be too. Whatever they would ask you is what the prompt is missing.

State the goal in one sentence

Say what you want done and what a good result is. “Help with my email” leaves the model to guess. “Rewrite this email so a customer who is annoyed about a late delivery feels heard, in under 120 words” does not.

Give the background

Why do you need it? What do you already have? Atlassian’s advice is to explain the situation, not just ask the question. Compare “How do I learn Spanish?” with “I move to Madrid in March and need to talk to shop staff and neighbours. What should I practise first?”

Say who it is for

The reader decides the tone, the words and what to leave out. Name them: “for senior engineers who missed the meeting”, “for customers who have never used the product”.

Give the format and size as numbers

OpenAI’s example is a product description. “Fairly short, a few sentences, and not too much more” becomes “a 3 to 5 sentence paragraph”. Words such as short, brief and a few mean different things to you and to a model.

Less clear:  Write a short summary of the report.
Clearer:     Write a summary of the report in 5 bullet points,
             then one sentence on what needs a decision.

Say what to do, not only what not to do

A list of “don’t” lines leaves the model to guess what you want instead. OpenAI and Anthropic both recommend saying what to do. Atlassian points out that stating what to leave out also helps. Do both: keep the limit and add the alternative.

Less clear:  Don't use jargon. Don't make it long.
Clearer:     Use plain words a new customer would know, and keep it
             under 100 words.

Cut filler and hedging

Models take words literally. “If possible, try to include…” makes the instruction optional. Write “Include…”. Capitals and exclamation marks add noise, not weight: a plain sentence with a reason works as well.

Put it together

Write a short email about our new feature. Make it good.

becomes:

Write an announcement email about our new export feature.
Audience: customers who use the product every week.
Background: it saves them about an hour a month, and we want them to
try it this week.
Format: under 120 words, friendly and plain, one call to action.

Check it as you write

Promptor runs these checks on your prompt in your browser and says why each one matters, with the source. It can not judge whether a prompt is good, only whether the usual parts are there. For a real review, see Review a prompt with Connect AI.