Everyone is building LLM routers, we deprecated ours

Manifest ran an LLM router for four months, classifying requests into complexity tiers and routing them across providers to cut costs, then killed it. A prompt alone does not reveal how hard a task is, prompt caching (cache reads 75 to 90 per cent cheaper) undercuts the savings, and switching models mid-workflow hurts consistency. Their conclusion: a good router stays sticky to one model, doing its job “by, ironically, not doing it”.

The HN thread broadly agrees that frontier models are now interchangeably good for everyday work, and that nobody has time to learn each model’s quirks when a new one lands every week. The consistency point rhymes with cognitive coverage: switching tools constantly means never really knowing them.