Knitwear development rarely starts with a complete answer. It starts with a set of questions to confirm: will the yarn create the intended handfeel? Can the gauge support the silhouette? Can the measurements and finishing stay consistent in bulk?
A useful product brief does not need to solve everything upfront. It does need to make the context, target, known constraints and open questions clear. That lets the first sample do real review work instead of becoming just another presentation.
When product direction, material choices and production standards move in the same line, brand teams and manufacturers can make decisions around the same physical product.