As AI increasingly facilitates code generation, the focus of software engineering is shifting towards writing precise specifications, a practice known as spec-driven development. This approach emphasizes the creation of detailed, structured documents that capture requirements, intentions, and constraints before code is generated, providing AI agents with refined context to ensure they deliver accurate and relevant solutions. In contrast to ad hoc, prompt-driven coding, spec-driven development encourages engineers to meticulously outline aspects like input/output formats, business rules, and performance requirements, allowing for more effective AI collaboration. This method not only enhances clarity and precision but also fosters collaboration through tools like Runbooks, which act as shared spaces for teams to align on execution workflows and maintain a knowledge base. As AI models advance, the ability to write comprehensive specifications is becoming a critical skill, enabling teams to tackle complex tasks and ensuring that software meets its intended purpose.