Begin with the reason this outsourcing versus in house software development should exist, not your preferred technology. Who will use the system, with what frequency, and what happens today? A vendor custom blockchain development who grasps the purpose can propose a cheaper route to it; someone handed only a list of screens prices the list as written.

Describe the scope as short scenarios: who does what, and what happens next. Every bit as useful, write down what the first release deliberately excludes. An explicit exclusion list removes more friction at delivery time than the rest of the brief combined. Also mark which parts are firm and which are still open — estimators price uncertainty, and concealing the open questions only hurts you.

Set out your constraints. These include the platforms and services involved, existing databases and their quality, regulatory obligations, traffic expectations, which devices matter and infrastructure that is already decided. Where a date is genuinely fixed, explain what drives it: an experienced team will often cut the right scope to hit it, but not if the date is a secret.

Write down what the word done means feature by feature. Clear acceptance criteria do not require any formal notation: a short list describing the expected behaviour is enough. This one section reduces the review at the end dramatically and removes the usual argument at handover.

To close, ask for a specific format. Ask for a breakdown by feature or module, the assumptions used, the risks the team sees and a range rather than a single figure. Take a broad range as useful information rather than evasion: it usually points to the part of the brief that needs work. At that point rewrite that part and ask for a new estimate — the next version will be the one worth planning around.