AI coding assistants are great at completing small tasks or features. But what do you do when you're working with more complex codebases and need to build in-depth features that require upfront planning? This talk makes the case for spec-driven development. I'll show how AI coding assistants can help break down complex tasks into three phases. We'll go from requirements gathering to technical design to task implementation. Using a real-world example, we'll look at the trade-offs of this approach and how you can start using it in your own projects right away.