Book: LLM Observability Pocket Guide: Picking the Right Tracing & Evals Tools for Your Team Also by me: Thinking in Go (2-book series) — Complete Guide to Go Programming + Hexagonal Architecture in Go My project: Hermes IDE | GitHub — an IDE for developers who ship with Claude Code and other AI coding tools Me: xgabriel.com | GitHub You look at last month's LLM spend and the line item that hurts is not the hard cases. It is the easy ones. The "hi", the "thanks", the "what's my balance" that you are paying flagship-tier prices to handle because you wired the whole product to a single model id and never wired it to anything else. Every easy request rides the same expensive lane as the hard ones, and the bill reflects that. Routing fixes this. Not load-balancing across providers, not failover, not a feature-flag dance. Routing in the sense your CDN routes traffic: each request gets sent to the cheapest model that can answer it correctly, and the rest go to the strong model.…