[feature] more configurable tool picking

[grutt]

The toolbox utility is the most opinionated api for calling LLMs which is against the core philosophy to allow devs to write what they need.

We've received some feedback [1] to make this more flexible or allow users to customize this utility.

Some ideas we're toying around with is to add more config or allow this method to be "ejected" into the codebase for users to directly extend.

[1] https://news.ycombinator.com/reply?id=44359338&goto=item?id%3D44329102%2344359338