Your Agent Engineering Has an Expiration Date

RAG is dying. Not because it was bad — because models got bigger. When context windows jumped from 4K to 128K tokens, the elaborate retrieval pipelines that engineers spent months building became unnecessary overhead. The model just reads the whole document now. The same pattern keeps repeating. Chain-of-thought prompt templates? Models now reason natively. Custom JSON parsers for tool outputs? Function calling handles it. Retry loops for hallucination? Newer models hallucinate less. Each model generation quietly deletes a category of engineering work. This raises an uncomfortable question: how much of your current agent engineering will survive the next model upgrade? Two Kinds of Engineering Not all agent engineering is created equal. There's a split that most practitioners feel intuitively but rarely name: Compensatory engineering patches model weaknesses. It exists because the current model can't do something well enough, so you build scaffolding around it. RAG for small context wi