RAG vs Agent: The Decision That Broke My System (And How I Now Enforce It Upfront)

Most people treat the RAG-vs-Agent question as a technical preference. Pick whichever feels right, adjust later.

I did that. It cost me two full rebuilds.

Here's the decision framework I've landed on — and the tool I built to enforce it before the first line of code gets written.

The Mistake: Treating Architecture as Reversible

I was building GrowthOS, a four-module internal talent development platform. When I hit module three — personalized learning path generation — I reached for RAG out of habit. I'd just built a solid RAG knowledge base in module one. The pattern was familiar.