Check out the source code to the vercel AI SDK. I’ve noticed that they broker calls out to various LLMs and then seem to return the cost as part of the response. So I’m thinking that this data could well be in there somewhere. Away from my desk right now so can’t check.

I do this with other tools

1. Pull some large tech company’s open source’ tools’ JS file 2. Extract an internal JSON blob that contains otherwise difficult information 3. Parse it and use what I need from within it for my tool