OpenSpec is an open-source framework solving one of the most quietly expensive problems in agentic development — the gap between what you mean and what your agent builds. Keystone produced a spec ad that translates a deeply technical philosophy into something immediately intuitive, walking through how spec-driven development works in practice: defining the blueprint before the agent touches the code, catching mistakes before they compound, and building a shared source of truth your whole team works from. The creative challenge was making infrastructure feel urgent — and in a world where generating code is cheap but correctness isn't, the product makes that case on its own.