Begin with the problem you are solving, not a feature list. Who will use the system, how often, and monolith vs microservices comparison how is the job done today? A vendor who grasps the purpose will suggest a cheaper route to it; someone handed only a list of screens will price the list as written.

Set out the scope as user stories or scenarios: a walk through each important path. Equally important, state explicitly what is out of scope. An explicit exclusion list prevents more argument at delivery time than the rest of the brief combined. Mark too which items are decided and which are still open — estimators price uncertainty, and pretending everything is fixed helps nobody.

Set out your constraints. The list covers the platforms and aws development services involved, existing databases and their quality, regulatory obligations, expected load, target platforms and any technology you are committed to. If there is a hard date, explain what drives it: a good team is usually able to rearrange the plan to hit it, but only if they know it exists.

Define what done means for each item. Testable acceptance criteria do not need any formal notation: best aso agency a short list stating what must be true when the feature works will do. This single habit compresses acceptance testing considerably and eliminates the usual argument at handover.

To close, state what you want in the response. Ask for a breakdown by feature or module, a written list of assumptions, the risks the team sees and an optimistic and a pessimistic figure. Read a wide range as useful information rather than evasion: it usually points to where your description is thin. Then rewrite that part and ask again — the revised figure tends to be much more reliable.