> The phrase "frontier model" is starting to mean two things. One is a checkpoint. The other is a system boundary.

LLM-isms aside, I don't think we want this to be the case? An LLM, for all its complexity, is something that can be reasoned about. It's picking the next token, until it hits an EOS. The semantics imposed on those tokens (reasoning ,tool call, etc.) are up to the user('s harness) to decide and act on. The more that's pushed behind the facade, the harder it is achieve sufficient understanding of the model's behavior s.t. one can compose it into larger abstractions. Perhaps the performance (and the adherence to an interface/contract) compensate? But swapping from Opus or 5.5 to this or Fugu seems like a much bigger change than swapping between different 'base' models.

I thought all model providers are doing this under the hood anyway in their UI?

They certainly seem to when A/B testing different models, and Fable routes to Opus 4.8 when guardrails fail.

Also, openrouter recently released a fusion router - https://openrouter.ai/blog/announcements/fusion-beats-fronti...

Every one has been saying it’s all about the harness. This is an obvious result of that.

I think an optimal solution would be to have more seamless integration between harness and router roles. As each are only half the picture

Solutions like these are really cementing the view that LLMs are becoming a commodity

Can we please stop submitting fully AI-generated text to HN?

This should help with better utilizing a heterogenous collection of inference hardware.