separation of concerns

Separation of concerns is an architectural discipline that isolates distinct responsibilities into independent layers so that a failure in one cannot corrupt another. In LLM-driven systems this means keeping retrieval—the read-only source of truth—architecturally separate from presentation, where the model renders, synthesizes, or judges output, ensuring that hallucinations, fabrication, or rendering errors are contained as a blast radius rather than poisoning the underlying corpus. Equally critical is forbidding any layer from auditing itself: verification must be performed by an independent, deterministic process because the producer of an artifact is the worst judge of its own correctness. The principle extends beyond text pipelines to identity and reasoning, favoring borrowed containers over copied credentials and explicit detection stages over conflating collection with judgment. The net effect is graceful degradation—each layer remains trustworthy and fixable on its own terms, and operators always know precisely how much to trust each surface.