Design brief, written.
Also called: Design instruction · Brief document · Project brief · Scope of work
A short instruction that turns the agreed MVP scope into objectives, hard constraints, success criteria, deliverables, and what is out of scope.
Write the brief as an instruction, not a wishlist. Name the objective, the hard constraints, the testable success criteria, the deliverables, and what is out of scope. If a designer could meet it two contradictory ways, it is too loose.
What a design brief is
A design brief is the document that hands the agreed MVP scope to whoever designs it, written so they can act without coming back to ask what you meant. It states the objective, the constraints they cannot break, the criteria the result will be judged against, what they owe back, and what they must not build. It is an instruction, not an aspiration.
The test of a good brief is simple. Could a competent designer who has never met you read it and produce something you would accept? If the answer is no, the brief is leaking decisions to the design stage, and decisions made there cost ten times what they cost on paper. A loose brief feels generous. It is not. It just defers the argument to a more expensive room.
Why briefs go wrong
- They list wants, not bounds. “Premium feel” is a want. “Ceramic shell with a wood element, must read as a counter object at £149” is a bound a designer can hit or miss.
- They skip the out-of-scope list. The single most-skipped section, and the one that prevents the most rework. What you forbid matters as much as what you ask for.
- They confuse the brief with the specification. The brief sets direction and bounds; the specification (05.10.02, next) pins the numbers. A brief that tries to be both ends up being neither.
A worked design brief
The clearest way to write one is to fill five fields honestly. Here is the proofing box brief, the one we worked from in the pilot, so you can see the shape of a real instruction rather than a generic template.
Five fields, one page, no slack. Notice the out-of-scope row does as much work as the objective: it stops the designer solving a problem you deliberately chose not to solve.
How it fits the bigger picture
Design brief is activity 05.10.01 in the framework, the first activity of Stage 05 Define. It takes the MVP scope agreed at the close of Stage 04 Evaluate and turns it into an instruction. It feeds straight into the specification (05.10.02), which pins the brief’s bounds into measurable numbers and tolerances.
What it can do
It gives the design stage a single source of truth: one page that says what good looks like and what it must not become. When a designer proposes something off-target, the brief settles it without a meeting. It also protects the bill of materials and the price band from quiet creep, because both are written down as bounds, not hopes.
What it can’t do
It can’t carry the engineering numbers; that is the specification’s job. A brief that hold 26°C ±0.5°C is direction, but the tolerance stack, the heater rating and the test method belong in the spec. The brief sets the destination; the specification draws the map.
See the full 10-stage process →
Try it yourself
Take your agreed MVP scope. Write five short fields on one page: objective, hard constraints, success criteria, deliverables, and out of scope. Then hand it to someone who has never seen the project and ask: “could you build the wrong thing and still satisfy this?” Every gap they find is a decision you were about to leak into the design stage. Tighten it before anyone opens CAD.
Want a guided first pass? Start the Free Sprint → and the GPT will help you frame the scope before you brief it out.
Your design-brief checklist
Project notes: the brief that fit on one page
▸ From the notebook · optional reading
Writing the proofing box brief with Dan and Anna Hartley in Stockport, and the one line in the out-of-scope list that saved the budget.
3 min read · click to open
The MVP was already cut to one capacity, ceramic and wood, no app. Dan wanted to “just send the maker a sketch and see what comes back”. I asked for half an hour first. “One page. Five fields. Then we send it.”
What ended up on the page
Objective: a counter-top box for two 1kg dough balls, holding a steady overnight prove, that reads as a premium object rather than a kitchen gadget. Hard constraints: 26°C give or take half a degree, under 30W, no app, ceramic with wood, a knob and an OLED, single capacity, UKCA and BS EN 61010, a £38–55 bill of materials. Success criteria: holds the band on a bench test through a Stockport winter kitchen, sells at £149, sets with the knob alone.
The line that earned its keep
The out-of-scope row read: “No phone connectivity. No second SKU. No extra presets. Nothing that pushes the bill of materials past £55.” Two weeks later the Stoke-on-Trent maker came back with a lovely concept that quietly added a decorative ceramic collar, more parts, more cost. Without the brief it would have felt rude to refuse. With it, I just pointed at the line. We pushed the collar to a possible V2 finish and kept the budget intact.
The whole brief was a single side of paper. The maker never had to ring us to ask what we meant, the Manchester PCB team worked from the same page, and the first design review was about quality, not about scope. That is the entire point of writing it down first.
— Define stage, project notes, 2026
— Next in Define → Specification