I Let An AI Coding Agent Touch My Codebase Here’s What It Broke, Saved, And Secretly Cost Me

I let an AI coding agent loose inside a real codebase, and yeah, it was impressive for about five minutes. Then the weird stuff started. A clean refactor broke auth, renamed things no one asked for, and quietly added a cost line item nobody mentions in demos. But it also saved hours on boring edits, test scaffolding, and repo search. That’s the truth most blog posts skip. AI coding agents are useful, but they are not magic, and they are definitely not free. If you’re thinking about shipping fast