Every Decision Was 'Right' — Until the Project Rotted Anyway
Teams mistake tidy structure for coherent design, so production outages and multi-month rewrites come as surprises. AI code generation lowers the cost of creating near-duplicate components, which makes degradation accrue faster unless someone actively consolidates.
The trigger was a checkout feature. Adding a "corporate procurement" field required touching six directories, none named "checkout". A two-year-old validator hidden in `utils` vetoed the new fields and broke production for enterprise clients. The real problem wasn't carelessness; the scattered placement made it impossible to verify completeness.
A medical CRM team's retrospective gave it a name: Architecture Decision Degradation. Each choice — Redux-Toolkit, createAsyncThunk, optimistic updates — was defensible, yet three slices became ten, 41% of bugs were state-related by month 12, and a three-month rewrite loomed by month 16. A migration that moved 143 components unchanged into a new skeleton, plus a 5647-line Vue component with a reverse import cycle, showed that moving house without consolidating just relocates bad habits.
AI sharpens the trap: it generates a new component instead of checking for an existing one, making duplication cheaper than reuse. The author's new yardstick is cohesion — code that changes together for the same reason should live together. Convergence means deciding what should not exist, not just rearranging what does.
ADD differs from technical debt in that each decision is rational at the time; the failure only becomes visible when a dozen rational decisions intersect, making retroactive blame pointless.
The 5647-line component and the import cycle show that even enforced directory structure and lint rules cannot prevent a codebase from becoming untouchable if consolidation is never performed.
AI's role is not to introduce duplication but to remove the cost barrier that previously made reuse the default choice, so teams must institutionalize consolidation rather than rely on individual discipline.