LLMs & Models4 min read
Systems Design / LLM Infrastructure
The real cost of model routing has nothing to do with sticker price
Across 417 agentic tasks, GPT-4.1 cost nearly double Claude Sonnet despite lower sticker pricing, because caching rewrote the math. A deep-dive on why model routing fails as classification, and how optimization-based routers beat difficulty-based ones.
2026-07-15