I've been using Opus 4.6 for some security related work (it has much looser guardails that later opus models) and last week, all of a sudden, the processes started to fail. It wasn't the main model blocking commands but the auto mode classifier changed how it worked and it started blocking the main models commands.
That's one specific incident, but it does have a wider potential problem which is, if you use Anthropic's harness you'll always be at the risk of sudden breakage from server-side changes that are opaque to the end user, which is a tricky one for building long lasting processes.