150,000 Lines of Vibe Coded Elixir: The Good, The Bad, and The Ugly

Reflections on 6 months of AI-Native Development

TL;DR:

• Good: AI is great at Elixir. It gets better as your codebase grows.
• Bad: It defaults to defensive, imperative code. You need to be strict about what good Elixir looks like.
• Ugly: It can’t debug concurrent test failures. It doesn’t understand that each test runs in an isolated transaction, or that processes have independent lifecycles. It spirals until you step in.
• Bottom Line: Even with the drawbacks, the productivity gains are off the charts. I expect it will only get better.