Do all your agent's LLM calls really need a frontier model? NVIDIA's Switchyard ran the numbers — and the results are surprising.
Title: Switchyard Agent Routing Benchmark
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TL;DR
Evaluated 145 multi-step agentic tasks (averaging 6.3 LLM calls each). 93% of calls were handled by a smaller model, achieving 74% cost reduction with only a 6-point accuracy drop.
Key Points
🎯 Frontier model needed for just 7% of calls
Out of all LLM calls, Claude Opus 4.8 was required for only 7%. The remaining 93% were handled by Nemotron 3.5 Lightning.
💰 74% cost reduction
Per-task cost dropped from $0.092 (Opus alone) → $0.026 (routed) → $0.006 (Lightning alone), while maintaining 80% accuracy.
📊 The surprising cost breakdown
Despite handling only 7% of calls, the frontier model consumed 68.4% of total spend. The judge model itself added another 21.2% of routed costs.
🔢 The formula for routing ROI
"Minimum offload rate = judge cost / (expensive model cost - cheap model cost)" — if the price gap is small, routing may not pay off.
⚡ Two deployment options
Run NVIDIA Switchyard as a standalone proxy server, or embed it as middleware inside LangChain's Deep Agents framework.
Note: the eval suite had relatively easy tasks, so the benefit of routing could be even larger with harder workloads. Still, highly practical for agents that issue many calls per task.
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