Imagine a very fast new starter
Picture a new colleague on their first Monday. Bright, quick, well read, keen. They have never met your customers, never seen your templates, and have no idea that Marcus in finance hates bullet points. If you lean over and say "can you do something about the supplier thing", they will produce something. It will be wrong, and that is not their fault.
Every AI assistant is that colleague, permanently. Enormously capable, permanently on day one, and constitutionally unable to say "sorry, I have no idea what you mean". It will guess instead, in a confident voice, and hand you a polished draft about the wrong supplier.
A brief is what stops that happening.
In plain English
- Brief:
- The instruction you hand over: what to produce, for whom, to what standard, within what limits.
- Constraint:
- A hard limit. Length, tone, format, what to leave out, what must appear.
- Gap:
- Something the job needs that you did not supply. Left unmanaged, it gets invented.
- Assumption log:
- A short list at the end of the output saying what the AI filled in for itself.
The five parts
Every brief that works has the same five parts. You can write them in any order and they do not need pretty sentences.
One: the finished thing. Not the topic, the artefact. Not "the supplier thing" but "a one-page memo recommending whether we renew".
Two: who it is for. The audience decides vocabulary, length and how much background to include. "For our operations director, who knows the contract" is a completely different document to "for the board, who have never heard of this supplier".
Three: what good looks like. One sentence. "Good means the reader can make the decision without asking me a follow-up question." This is the part almost everyone skips and it is the part that does the most work.
Four: constraints. Length, tone, format, banned words, things that must not appear. Be specific. Under 400 words beats "keep it short".
Five: what to do about gaps. The instruction to ask rather than invent. Without it, missing facts become plausible fiction.
Number five is not optional. An assistant with a gap and no instruction will fill it. It will invent a renewal date, a headcount, a percentage. Everything around the invention will be correct, which is precisely what makes it dangerous.
FINISHED THING: [name the artefact exactly, including format]
AUDIENCE: [who reads it, what they already know, what they will do with it]
GOOD LOOKS LIKE: [one sentence describing success]
CONSTRAINTS: [length, tone, structure, must include, must not include]
GAPS: If anything is missing or ambiguous, do not guess. Produce your best
version using clearly marked placeholders in square brackets, then list your
open questions at the end under the heading OPEN QUESTIONS.
Checkpoint
Five parts: the finished thing, the audience, what good looks like, the constraints, and what to do about gaps. The fifth is the one that saves you from confident fiction.
Watch it work
โ Weak prompt
Prompt
Write something about our supplier renewal.
Output
Our partnership with the supplier has delivered significant value over the past year. As we approach the renewal window, it is worth reflecting on the strengths of the relationship and areas for continued growth.
It has invented a positive verdict, a timeframe and a tone, because it had no verdict, timeframe or tone to work from. Nothing here survives contact with a real decision.
โ Good prompt
Prompt
FINISHED THING: a one-page memo recommending whether we renew our stationery supplier. AUDIENCE: our operations director, who knows the contract but not the recent problems. GOOD LOOKS LIKE: she can decide renew or not without coming back to me. CONSTRAINTS: under 400 words, plain English, a recommendation in the first two lines, then the evidence, then the risks of switching. No filler openings. GAPS: use square-bracket placeholders and list open questions at the end.
Output
A memo opening with a clear recommendation, three pieces of evidence, two switching risks, and an OPEN QUESTIONS list asking for the renewal date and the current annual spend.
Decision-ready, and it told you exactly which two facts it needed from you rather than making them up.
Say the standard out loud
"What good looks like" feels awkward to write until you try it once. Compare "make it professional" with "good means a customer who is already annoyed finishes reading it feeling taken seriously". The second one steers every sentence.
GOOD LOOKS LIKE one of these, pick the closest and edit:
- The reader can make the decision without asking me anything else.
- A busy person gets the point from the first two lines alone.
- Someone who joined last week could follow these steps unaided.
- An annoyed customer finishes it feeling taken seriously, not managed.
- Nothing in it would embarrass me if it were forwarded to the whole company.
Constraints are kindness
Vague briefs produce padded output. Specific constraints produce usable output. Give numbers wherever you can.
CONSTRAINTS
Length: under [300] words / exactly [5] bullets / [1] page.
Tone: [warm and direct / neutral and factual / lightly informal].
Structure: [recommendation first, then evidence, then risks].
Must include: [the deadline, the cost, the named owner].
Must not include: [customer names, guesses at figures, the phrase moving forward].
Reading level: someone outside my team should follow it with no jargon.
Before you write anything, list the facts you need from me that I have not given you.
Number them, keep it to the ones that would actually change the output, then stop.
I will answer, and only then should you produce the [document].
That last one is the highest-value habit in this course. Thirty seconds of questions up front routinely saves three rounds of rewrites, and the questions themselves often reveal that you had not decided something yourself.
Briefs are reusable, questions are not
The quiet bonus: a good brief is a template. The supplier memo brief becomes every memo brief with three words changed. Save the ones that work. By lesson six you will have a small collection of them, and that collection is worth more than any single clever prompt.
๐ Quiz
Question 1 of 4Which part of a brief do people most often skip, and which does the most steering?