4. Develop & Deliver

This is where the thing actually gets built — and where a lot of processes quietly break down, because design hands off a file and disappears. Here, design and engineering run in the same cycle: edge cases, loading states, error states, and interaction detail get specified as they're needed, not guessed at by whoever's holding the ticket.

The result is fewer surprises at review and fewer screens that only work for the happy path. Once it's built and holding together end to end, it moves to Release & Monitor — out into the world, with a way of watching what actually happens next.

In practice, that's a shared task board where design and engineering close tickets against the same spec — not two separate to-do lists that drift apart.