When I shipped the Neuron AI official router package a few weeks ago I received the same question from many devs, just worded differently: can it send the hard requests to the strong model and the easy ones to the cheap one? It is the most natural rule to want. It was also the one rule I could not write cleanly, and that bothered me.
The router gives you a clean place to make that decision. You register a few providers, you set a rule, and the agent never knows it is talking to a proxy. But the rule has to return a provider name, and to do that judging the prompt difficulty you first need a definition of “hard” that exists in code. That is the part nobody had. The word was doing a lot of work in conversation and none of it in the editor.
How people fake difficulty today
If you go looking, the workarounds all have the same shape. Some people route by prompt length, on the theory that longer means harder. In practice a one line question about Italian contract law is short and genuinely hard, while a long pasted log that you want summarised is trivial. Length measures typing, not difficulty.
Others keep a list of keywords and route anything containing “legal”, “code”, or “calculate” to the premium tier. This works for a week. Then you are maintaining a dictionary forever, it misses every phrasing you did not anticipate, and it has no opinion at all about prompts in a language you did not hard code.
