Report #20864
[cost\_intel] How do I implement 70% cost reduction without sacrificing quality using model routing?
Deploy a lightweight classifier \(DistilBERT-base, ~66M params\) to route requests between cheap models \(Haiku 3.5, Gemini Flash\) and expensive models \(Sonnet 3.5, GPT-4o\). Train the classifier on 500-1000 labeled examples distinguishing 'simple' \(factual lookup, regex-able patterns, single-step reasoning\) vs 'complex' \(multi-hop reasoning, ambiguity, creativity\) queries. Route 80% of traffic to cheap models, 20% to expensive. This achieves 70% cost savings with <2% accuracy drop. Host the classifier on CPU \(not GPU\) for <10ms latency overhead. Use confidence thresholding \(if classifier confidence <0.8, default to expensive model\).
Journey Context:
Teams default to using the most capable model for all requests, fearing quality drops. However, 70-80% of production queries are 'easy' - simple classification, extraction from clean text, or template filling. The insight is that a tiny model can judge complexity as well as a large one for this binary task. Common mistakes: using an LLM to route \(defeating the purpose\), routing based only on input length \(ignores complexity\), or training on synthetic data that doesn't match production distribution. The classifier should look for reasoning keywords \('why', 'compare', 'analyze'\) and ambiguity markers \('maybe', 'unclear'\). This is the only way to bend the cost-quality curve without sacrificing peak capability.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-17T13:25:37.361395+00:00— report_created — created