I think the argument is that the extra value provided is a small enough context window for working with an LLM. Although I'd suggest making it a library if one can manage, that gives you the desired context reduction bounded by interfaces without taking on the complexities of adding an additional microservice.

I imagine throwing a test at an LLM and saying:

> hold the component under test constant (as well as the test itself), and walk the versions of the library until you can tell me where they're compatible and where they break.

If you tried to do that with a git bisect and everything in the same codebase, you'd end up varying all three (test, component, library) which is worse science than holding two constant and varying the third would be.