🔍Cascade Architecture Solves RAG Auditability Issues
Your LLM pipeline needs a reality check
TL;DR
A three-stage cascade architecture for retrieval augmented generation (RAG) systems ensures auditability and cost efficiency, reducing model calls by 6X while improving decision consistency.
Most teams route ambiguous cases straight to the LLM in RAG systems, but this approach falls apart under scrutiny. A new cascade architecture treats the LLM as an escalation path rather than a front-line solution. This three-stage pipeline—deterministic stage one, retrieval stage two, and LLM stage three—cuts inference costs by 6X while ensuring decisions are fully explainable and consistent. The system's evaluation set should oversample cases reaching stage three to test its judgment accurately.

Key Points
Stage one clears over half of volume with deterministic lookups, no inference needed (fact 8).
Retrieval stage two pulls specific evidence relevant to ambiguity: prior decisions, documents, or precedent (fact 9).
LLM call only sees unresolved cases from stages one and two, cutting costs by 6X compared to an all-LLM baseline (fact 10).
Prompt design must balance missing genuine issues vs. incorrectly flagging them, treating uncertainty as a reason to escalate (facts 11-12).
Confidence score threshold determines when cases go to human review instead of auto-resolution, regardless of model classification (fact 13).
Why It Matters
If you're building RAG systems for high-stakes decision-making in regulated environments, the cascade architecture is a must. It ensures decisions are fully explainable and consistent under scrutiny, reducing costs by cutting LLM calls by 6X compared to an all-LLM baseline (fact 10).
Frequently Asked Questions
Why does this matter?
If you're building RAG systems for high-stakes decision-making in regulated environments, the cascade architecture is a must. It ensures decisions are fully explainable and consistent under scrutiny, reducing costs by cutting LLM calls by 6X compared to an all-LLM baseline (fact 10).
What happened?
A three-stage cascade architecture for retrieval augmented generation (RAG) systems ensures auditability and cost efficiency, reducing model calls by 6X while improving decision consistency.
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