Executive Summary Agentic RAG systems combine: ●       Reasoning models  ●       Retrieval systems ●       Tool use (increasingly via MCP) ●       Memory (short-term, long-term, and now tiered/benchmarked) ●       Workflow orchestration ●       Governance controls ●       A harness layer that governs all of the above The goal is not maximum autonomy. The goal is reliable, auditable, policy-aligned autonomous execution. Modern production systems optimize for: ●       Accuracy ●       Cost efficiency ●       Safety ●       Explainability ●       Human oversight ●       Operational resilience NEW IN 2026  The single biggest framing shift: the model is now understood as the smallest part of the system. Practitioners increasingly describe production agents with the equation  Agent = Model + Harness,  where the harness — not the model — determines reliability, and benchmarks such as Harness-Bench show that swapping the harness around an identical model pool can move task-success scores by over 20 points.