☀️ AI Morning Minute: Model Routing
Not every question gets the expensive model.
Model routing is the practice of automatically sending each request to whichever AI model is best suited to handle it. Instead of one model answering everything, a system sits in front of several and decides where each question should go. Simple questions get a fast, cheap model. Hard ones get the slow, expensive one that thinks carefully. If you’ve noticed ChatGPT or Claude quietly picking a mode for you rather than making you choose, that’s routing doing its job.
What it means
The reason routing exists is cost. The most capable models are meaningfully more expensive to run than the lighter ones, and most of what people ask doesn’t need them. Reformatting a list or answering a factual question is not the same work as debugging code or analyzing a contract, but if everything goes to the flagship model, you pay flagship prices for both.
A router looks at the incoming request and makes a quick judgment about how much horsepower it needs. That judgment might be based on the length and complexity of the question, whether it involves reasoning or images, or how the user has phrased it. Then it hands the request to the appropriate model and returns the answer, usually without telling you which one it picked.
This is different from Mixture of Experts, which people sometimes confuse it with. Mixture of Experts routes between specialized sections inside a single model. Model routing chooses between entirely separate models. Same basic instinct, different level.
Why it matters
It’s why AI products can afford to be free. Routing cheap questions to cheap models is what makes a free tier survivable.
It explains inconsistent answers. If the same question gets different quality on different days, routing may have sent it somewhere different.
It’s becoming invisible on purpose. Providers increasingly decide for you, which is convenient right up until you wanted the better model.
Simple example
Think about how a hospital handles an emergency room. Not everyone who walks in sees a surgeon. A nurse at intake takes one look, asks a few questions, and decides where you go: minor cuts to the fast track, chest pain straight to cardiology. Nobody thinks this is a downgrade. It’s the only way the hospital treats everyone without running out of surgeons by noon. Model routing is that intake nurse, and the reason you rarely notice it is that it’s usually right.