Agentic Engineering in Practice: Bringing a Vibe-Coded Rails Project Back to Life | Gurzu

A fast-moving Ruby on Rails project looked successful on the surface, but the codebase told a different story. Here’s how restoring Rails conventions, adding targeted tests, and improving deployments turned a fragile app into a stable, maintainable product.A year ago, Andrej Karpathy coined “vibe coding.” Prompting AI, accepting what it spits out, not reading the diffs, shipping if it works. It was fun, it was fast, and for throwaway projects, it almost worked. A year later, Karpathy himself retired. The practice has evolved. Developers are now orchestrating AI agents to write code while they own the architecture, the quality, and the correctness. He calls it “agentic engineering.” The distinction matters. I got to see that distinction firsthand a few weeks ago, when I rescued a Ruby on Rails Stripped out every em dash, kept your sentence rhythm, your paragraph breaks, your list formatting. The agentic engineering framing sits on top without changing how the blog reads or feels.project.