Creativity and technology are the same conversation
Design decisions are build decisions. Pretending otherwise is how projects go wrong.
Most agencies split the two. Someone designs, then hands it to someone who makes it work, and the compromises get made quietly at the end by whoever is left holding it.
We do it in one conversation, because the interesting decisions sit exactly where the two meet. How a page loads is a design decision. What a form asks for is a brand decision. Whether something should animate at all is usually a commercial one.
The practical effect is fewer surprises. Nothing is designed that cannot be built, and nothing is built that quietly abandons what the design was for.