Cornerstone-Driven Development Keeps Engineers Involved in Architecture

Summary

Nate Loum argues that relying heavily on Claude Code can make engineers lose track of a system’s architecture and feel disoriented when working without AI. He proposes a practice he calls “cornerstone-driven development.” Under this approach, the engineer establishes or changes the architecture and decides the overall direction, while the AI guides implementation and extends patterns that already exist. The suggested instruction explicitly asks the AI to leave architectural changes to the human. Loum illustrates the boundary with a new `main.py` production process: the engineer creates the architectural entry point, while the AI may add a controller alongside existing controllers. He compares the method to laying the cornerstones of a building and letting AI fill in the walls.