CROFTC: how to write a prompt that works

A prompt is a brief, not a wish

The model starts with nothing. It has never seen your project, your customer or your deadline. Every gap you leave, it fills with a guess. A bad answer is usually six guesses in a row.

What most people type

Write something for my bakery.

The model now invents a bakery, an audience, a tone, a length and a format. All of its choices, none of yours.

What the same request becomes

Context: I run Hearth, a small bakery on a residential street. Our site gets about 40 visitors a week and almost no online orders. Role: You are a copywriter who has written for local food shops for fifteen years. Objective: Rewrite the homepage opening so a first-time visitor understands what we sell. Format: Three options, each a headline under eight words, plus two sentences of body. Tone: Warm and plain, like a neighbour talking. No exclamation marks. Constraints: Under 90 words each. Mention sourdough once. Do not invent reviews or opening hours.

Six decisions made by the person who knows. Same model, same request, a completely different answer.

CROFTC is the list of those six decisions, in the order they help most: the scene first, then who is speaking, then the target, then the shape of the answer, then its temperature, then its fences.

You are not learning a trick. You are learning to write a brief, the same skill a good manager uses when handing work to a person. The model is a very fast colleague with no memory of yesterday.

Metal letterpress type sorted into the compartments of a wooden case — Each character has its compartment. Nothing is left to memory, and nothing is guessed.

Close view of an Imperial typewriter, its keys and carriage rail in warm light — Precise output from an imprecise brief is still imprecise. The typing is never the hard part.

The six fields, one job each

Read the letter, then read what it asks. Each field removes one place where the model would otherwise have to guess. You do not need all six every time, but you need to know what you are leaving out.

CContext

What is the situation?

The model knows nothing about you, your project or what happened last week. Context is everything you already hold in your head and forgot to say: who this is for, what is already built, what the deadline is, what "this" refers to. Without it the model invents a scenario, and its invention is almost never yours.

Write the facts a new colleague would need on their first day. Names, numbers, the state of things. Two clear sentences beat a paragraph of throat-clearing.

Weak

Fix my website.

Strong

My site gets 40 visitors a week. It was written in 2019 and still says we deliver, which we stopped doing.

Tip. If you would have to explain it to a new hire, it belongs in the context. If it belongs to the task, it goes later.

RRole

Who should answer?

A role tilts the whole answer. The same question answered by a cautious accountant and a bold art director lands in different places. Naming an expertise tells the model which drawer to pull from: its training on marketing, on law, on editing, on teaching.

Name a real trade or a real vantage point, not an attitude. "You are a helpful assistant" is not a role. "You are a pastry chef who has written menus for twenty years" is.

Weak

You are a helpful assistant. Be an expert.

Strong

You are a copywriter who has written for neighbourhood food shops for fifteen years.

Tip. If the role does not change the vocabulary or the priorities of the answer, it is decoration. Cut it.

OObjective

What is the one outcome?

"Help me with the homepage" is not an objective. "Rewrite the opening so a first-time visitor understands what we sell" is. A vague objective makes the model cover the whole map instead of hitting the target, and coverage is not help.

Make it specific enough that you could tell whether it had been done. One outcome per prompt. If you have two outcomes, you have two prompts.

Weak

Make the website better.

Strong

Rewrite the homepage opening so a first-time visitor understands what we sell in five seconds.

Tip. If you could only ship one change from this prompt, what is it? That sentence is your objective.

FFormat

What shape is the answer?

Format is what the answer looks like: a list, a table, three options, a paragraph, a script in scenes. If you do not say, you get a wall of text, which is a format the model chooses for you. Say the count and the unit: three headlines, each under eight words.

Format also sets how much room the model takes. "Three options" is a different job from "the best option".

Weak

Give me some ideas for the headline.

Strong

Three headline options, each under eight words, then one sentence saying which you would ship and why.

Tip. The number is a format. "Three" and "ten" produce different work. Choose the number you can actually use.

TTone

How should it sound?

Tone is the hardest thing to describe and the easiest to lose by leaving out. "Professional" is not a tone; it is a shrug that produces the same voice as every other page. Give a feeling and a reason: warm but not sentimental, plain like a postcard from a friend, dry with one quiet joke.

One precise phrase beats a paragraph of adjectives. A prohibition helps as much as a description: no exclamation marks, no jargon, never the word "artisan".

Weak

Make it sound good and professional.

Strong

Warm and plain, like a neighbour talking. No exclamation marks, never the word "artisan".

Tip. If you cannot name the tone, give one sentence you do like as a reference. A sample is worth ten adjectives.

CConstraints

What are the limits?

Constraints are the negative space that makes the answer usable: the length, the words to avoid, the facts it must keep straight, the things it must never do. A model told what not to do wanders far less than one told only what to do.

This is the most skipped letter and often the most useful. It is also where you stop the model from inventing: no fake reviews, no made-up opening hours, no invented awards.

Weak

Keep it short and do not make anything up.

Strong

Under 90 words. Mention sourdough once. Do not invent reviews, awards or opening hours.

Tip. Write your constraints last, after you have seen the answer once. The first draft shows you what needs a fence.

One prompt, all six fields

Here is the bakery request written out in full. Read it once. Every paragraph is one letter of the acronym, and nothing in it is filler.

Nineteenth-century engraving of a printer's composing case, its trays divided into a compartment per letter — A composing case, 1873. Every letter has its compartment, and the compositor knows where each one is. A prompt works the same way.

C Context

I run Hearth, a small bakery on a residential street. Our site gets about 40 visitors a week and almost no online orders. The homepage was written in 2019.

R Role

You are a copywriter who has written for neighbourhood food shops for fifteen years.

O Objective

Rewrite the homepage opening so a first-time visitor understands what we sell and wants to visit this weekend.

F Format

Three options. Each one a headline under eight words, then two sentences of body. After the three, one line saying which you would ship and why.

T Tone

Warm and plain, like a neighbour talking. No exclamation marks. Never the word "artisan".

C Constraints

Under 90 words per option. Mention sourdough once. Do not invent reviews, awards, prices or opening hours.

Send that, and you get three usable headlines instead of a page of generic copy. Change the context and the answer changes with it. That is the return on the six fields: the work you do once, in the prompt, saves the work you would otherwise do five times, in the edits.

Write your own, field by field

The boxes start with the bakery example. Replace each line with your own request. The prompt assembles on the right as you type, so you can see how the six pieces hold together before you send anything.

C Context: what is the situation?

R Role: who should answer?

O Objective: what is the one outcome?

F Format: what shape is the answer?

T Tone: how should it sound?

C Constraints: what are the limits?

Your prompt

Where it goes wrong

Six habits that quietly ruin a good prompt. Most of them come from doing too much, not too little.

Everything at once

A thousand words of background pushes the actual ask out of the model's attention. It answers the mood of the document, not the question in it.

InsteadKeep context to what changes the answer. Put the objective near the top, or repeat it once at the end.

Role as decoration

"You are a genius" or "act as an expert" changes nothing. The model has no idea which expertise to reach for.

InsteadName a trade or a vantage point: an editor at a local paper, a nurse explaining a discharge, a parent of a picky nine-year-old.

Contradictory constraints

"Short but cover everything in detail" is two orders. The model picks one at random and you blame it for the other.

InsteadRank them. Say which one wins when they collide, or split the request into two prompts.

No format

Left alone, the model writes an essay with a summary on top. You wanted a table.

InsteadSay the shape and the count: three rows, with name, price, and a one-line description.

Tone by adjective

"Professional", "engaging", "friendly" are the most common words in prompts and the least useful. Every model reads them as the same voice.

InsteadGive one sample sentence you like, or name a publication, or name a prohibition.

One prompt for everything

Reusing the same frame for a legal question and a birthday card gives you two mediocre answers.

InsteadRebuild the six fields for each task. The frame is the habit; the content is never the same.

Printed chart of an old type case, marked Upper Case and Lower Case, with one compartment per letter — "Upper Case, Numb. II" and "Lower Case, to Numb. II": a printed map of where every letter lives. The six fields are the same kind of map.

The questions people ask

Short answers to the things that come up first.

Do I need all six every time?

Almost always, yes. Each field removes one place where the model guesses. Start with all six. Once you have used the frame a dozen times you will know which one your kind of task can drop, and you will drop it on purpose rather than forgetting it.

Does the order matter?

Yes, and the acronym already has the right one. Context and Role set the scene, Objective points at the target, then Format, Tone and Constraints shape the answer. Put the objective last and the model can bury it under the material in front of it.

Is CROFTC just a long role prompt?

No. A role is one letter of six. "You are a copywriter" is a good start and a thin finish, because the model still does not know your situation, your target, your shape or your fences. CROFTC is what you build around the role so the role has somewhere to work.

How long should each field be?

One or two sentences, mostly. The aim is specificity, not volume. If a field needs four sentences, it is probably two fields: your format trying to also be a constraint. Split it and address each one honestly.

What if I do not know the tone or format yet?

Say so, and ask the model to help you choose. "Suggest three tones that would suit this bakery and a format for each" is a legitimate CROFTC prompt. You have moved the unknown into the objective instead of leaving it silent, and naming what you do not know is still more useful than pretending.

When should I skip the frame?

For a one-line lookup, skip it. "What is the capital of Peru" needs no brief. Use the full frame for anything you will send more than once, anything you will edit, or anything where a wrong guess costs you time.