When the Code Rots

Your agent's code can look perfect and still rot from the inside. Ada and Boris walk through the three ways it happens: the copy-paste explosion — the agent reinventing the same little utility instead of reusing yours, at roughly eight times the duplication rate of human-written code; phantom completions — features it cheerfully calls "done" that were never actually run; and architecture erosion — a clean, layered design quietly collapsing as the agent takes one shortcut after another. The through-line: every one is invisible at the level of a single change and only shows up when you step back and look at the whole project.

From Chapter 2 of *Harness Engineering for Vibe Coders* by J.M. Crider — go deeper at hamiltonroadagility.com/vibe