How do you design cost-aware routing in multi-model LLM systems?

Cost-aware routing selects models based on query complexity, latency constraints, and budget limits.

Multi-model systems often include small, medium, and large LLMs. A routing layer classifies requests and selects the most cost-efficient model that meets quality thresholds. This is typically implemented using lightweight classifiers or heuristic rules based on token length, intent type, or semantic complexity.