Start with the business problem, not a list of screens. Which people will use this, how many times a day, and what happens today? A vendor who knows what you are trying to achieve often proposes a simpler way to reach it; someone handed only a list of screens can only price your assumptions along with the work.

Define what is included as user stories or scenarios: a walk through each important path. Every bit as useful, list what you are not building. An explicit exclusion list saves more friction later than almost anything else in the document. Indicate as well which decisions are settled and monolith vs microservices comparison which are still open — the difference changes the price, and pretending everything is fixed only hurts you.

Write down the hard constraints. This means systems you must integrate with, existing databases and their quality, compliance requirements, traffic expectations, supported browsers or devices and any technology you are committed to. If there is a hard date, say what depends on it: a team is usually able to rearrange the plan to protect it, but only if they know it exists.

Write down what the word done means for the important items. Acceptance criteria need not use formal language: a short list describing what must be true when the feature works will do. This one section compresses the review at the end by a surprising margin and removes most late-stage disagreement.

Finally, state what you want in the response. Require a task-level breakdown, the assumptions behind each number, the risks the team sees and a range rather than a single figure. Treat a wide range as useful information rather than evasion: it usually points to exactly which requirement is unclear. Then rewrite that part and graphql vs rest ask for a new software project cost estimate — the second estimate is much more reliable.