Start with the reason this software should exist, not a feature list. Who will use this, how often, and how we work with clients is the job done today? An estimator who understands the goal will suggest a simpler way to reach it; one who only sees the requirements as given prices your assumptions along with the work.

Describe the scope as concrete flows: a walk through each important path. Just as important, list what the first release deliberately excludes. An explicit exclusion list removes more disagreement later than any other single page. Indicate as well which parts are firm and which may still change — estimators price uncertainty, and concealing the open questions helps nobody.

Write down the hard constraints. The list covers the platforms and services involved, existing databases and their quality, compliance requirements, user volumes, which devices matter and stacks you cannot change. Where a date is genuinely fixed, explain what drives it: a team is usually able to resequence the work to protect it, provided they hear about it early.

Write down what the word done means for each item. Clear acceptance criteria need not use any formal notation: dedicated web team a short paragraph describing what must be true when the feature works is sufficient. This one section reduces the review at the end dramatically and eliminates the most common source of disputes.

To close, state what you want in the response. Ask for a task-level breakdown, a written list of assumptions, the main risks and a range rather than a single figure. Read a wide range as useful information rather than evasion: custom llm development it usually points to the part of the brief that needs work. Then tighten that section and ask for a new estimate — the next version is the one worth planning around.