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paxysyesterday at 5:11 PM10 repliesview on HN

Looking at all these releases it’s not a surprise that model routing is the fastest growing segment in AI right now.

There are 10+ LLM companies, each with dozens of models of different modalities, each model with multiple size variants, then different “thinking” levels, then agentic modes, “pro” modes, a “fast” option, standard vs flex vs batch execution. And of course each end combination has a different input/output/cache token price.

Companies that say “give me a prompt and I’ll route it to the most ideal and cost effective model and setting for you” are capturing a ton of value from a gap that model developers don’t seem to understand exists.


Replies

ai-xyesterday at 6:02 PM

Model Routing will always be done better by models themselves. Plus routing loses context making it more expensive and less reliable.

Model Routing is just Bitter lesson. The models themselves will get better at this and frontier companies will simply give that capability

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hnfongyesterday at 5:29 PM

Because they're trying very hard not to understand it.

Otherwise the expensive-yet-powerful model probably won't see much revenue. How much money is there in bleeding edge scientific research? There's a lot, but there's even more existing capital in paying people people to do college level paperwork, and the bulk of those traffic gets routed to the cheapest model.

You mostly don't need super powerful AGI to replace the paper pushers, but the frontier labs are trying to position themselves as being uniquely capable of producing super powerful AGI, and also be the ones replacing office workers.

Not sure how it will work out for them, but I think model routing is going to poke holes in that narrative. That's why I think they're trying very hard not to understand model routing exists.

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TeMPOraLyesterday at 6:01 PM

Who are the customers though? Honest question, I'd like to understand it.

For me, anything other than current best available SOTA for any task is unacceptable. The only routing rule I need is "the most powerful model I still have flat-priced quota available for". I mean, why settle for less?

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throw03172019today at 2:12 AM

How does model routing work if the prompt is static? Do the routers attempt to tweak the prompt to make it the best version for that model? For example, reading the “migration” guides for Claude Opus 4.6 -> Opus 5 is exhausting. Adding in all of the other models complicates it even more. Especially across vendors.

awonghyesterday at 6:32 PM

what's the threshold for model routing where you're willing to trust the router?

For coding my own work I don't trust the model router, and it would have to be shown to be to save a real dollar amount.

From a buying perspective it's a hard sell to save x but lose out on bugs you are probably introducing at an unquantifiable severity and frequency. How much is it worth to hedge your bets by doing every single inference request on the frontier model?

How much will it cost to go back later and fix things, but also the meta question of how to be able to decide on a hypothetical unknowable? (You'll never know how much better or worse your code was gonna be, it's untestable at a project level)

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owenthejumperyesterday at 8:16 PM

I am not convinced this will end up being a domain of the ‘routers’ vs the clients, as in harnesses themselves. Thoughts?

ModernMechyesterday at 7:58 PM

lol I had to get ChatGpt to explain to me the difference between 5.6 sol, 5.6 Terra, 5.6 Luna, 5.5, 5.4 mini, 5.3 spark, and then there is low, medium, high, extra high, max, ultra, and pro… I still don’t really know, it feels like ordering hot wings.

simianwordsyesterday at 5:47 PM

Openrouter should ideally kill in this space and make their model agnostic infra like memory, harnesses, chat applications.

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TacticalCoderyesterday at 6:57 PM

And it's not just that model routing is much cheaper: no longer than yesterday we got a post showing that routing between K3 and Fable 5 was more SOTA than either of those.

If that is true, model routing is here to stay.

It also seems to validate the minimalist approach of pi.dev, where sub-agents from the same company is not the preferred approach (pi.dev believes in neither sub-agents all from the same company nor MCP even you can do it if you want for pi.dev's philosophy is to do add any functionality you want to a minimal harness).

Now of course we'll get for a few weeks all the Anthropic fanbois and shills explaining that "sure, K3 was basically at the level of Fable 5 but now that Opus 5 is out, open-weights models are six months behind".