0.13.8 shipped bu-2-0-mini-preview as the ChatBrowserUse default, which
means Agent(task=...) with no llm - and every bare ChatBrowserUse() -
silently moved onto a preview model on upgrade, with no code change on
the caller's side.
Two problems with that. A preview id can change behaviour or be renamed,
so it is the wrong thing to reach by omission. And per-token price is the
wrong yardstick for an agent: total cost is tokens-per-step times steps,
and steps is a function of model quality, so a cheaper-per-token model
that needs more steps to finish can cost more and take longer. We do not
yet have a per-task benchmark number for mini to say which way that goes.
bu-2-0-mini-preview stays a first-class option: still accepted, still
priced, still what the examples demonstrate. It is just opted into by
name now rather than landed on by default. Revisit once the benchmark
number exists.
Saurav Panda
5953df7d2f