I used it extensively to debug a very thorny MySQL version upgrade. In my experience, it knows a lot about MySQL, and can reason about weird behavior very very effectively. A typical use is asking it something like, "Prior to my MySQL upgrade, my DB integration tests all passed, but now, they're non-deterministically failing with the following error. What could be causing this?" It then proposes hypotheses, which I either accept or push back on with new information. Surprisingly, this process led to it actually debugging a great number of my problems.