On the other hand, they can also use it against you...

Thereallo

Claude Code Is Steganographically Marking Requests

I inspected Claude Code for privacy reasons and found hidden system prompt markers based on API base URL and timezone.

This stuff is neither amazing nor egregious, imo. But it *is* sneaky. Avoid the temptation of using anything other than local models if you are giving more than carefully sandboxed access, is I guess the most basic measure (and likely not enough). View quoted note →