How do you define an open weight model? What's it even mean?

Sure.

I like to explain this using an analogy.

For example, let's imagine that you sit down at a five-star restaurant.

So, you order the dish, eat it, enjoy it, but you don't know the exact recipe, right? So you cannot step into the kitchen and you cannot tweak the dish, right? So these are what we call the closed-weight model.

So things like chat GPT, GPT for all from OpenAI, Cloud 3.5, Sonnet, Opus, Faber from Nontropic, Gemini from Google, et cetera, et cetera.

So you can only interact with these models via a website or an API.

Why would anybody choose a frontier model then? Or maybe can somebody define frontier models for me?