The other day I caught it changing the grammar and spelling in a bunch of static strings in a totally different part of a project, for no sane reason.

I've seen it do this as well. Odd things like swapping the severity level on log statements that had nothing to do with the task.

Very careful review of my commits is the only way forward, for a long time.

That sounds similar to what it was doing here. It basically took a function like `thing = getThing(); id = thing.id` and created `id = getThingId()` and replaced hundreds of lines and made a new API endpoint.

Not a huge deal because it works, but it seems like you would have 100,000 extra lines if you let Claude do whatever it wanted for a few months.