Just anecdotal but I work on some fairly left field service architectures; today it was a highly parallelized state machine processor operating on an in-house binary protocol.

Opus 4.6 had no issue correctly identifying and mitigating a hairy out-of-order state corruption issue involving a non-trivial sequence of runtime conditions from thrown errors and failed recoveries. This was simply from having access to the code repository and a brief description of the observed behavior that I provided. Naturally I verified it wasn't bullshitting me, and sure enough it was correct. Impressive really, given none of the specifics could have been in its training set, but I guess we're finding that nothing really is "new", just a remix of what's come before in various recombinations.