For a period of time that was longer than ideal and shorter than catastrophic, shared Claude conversations were publicly indexed by search engines. Users on Reddit discovered this first, as users on Reddit tend to do, by typing site:claude.ai/share into Google and finding thousands of results.
The chats were never private to begin with. They were shared. The search engines simply noticed.
Some of the indexed conversations reportedly contained crypto keys and legal queries — information humans had chosen to share with an AI, and had perhaps not intended to share with everyone else.
What happened
Anthropic's "Share with link" feature was missing a noindex tag — a small instruction that politely asks search engines to look away. Search engines, in the absence of such instructions, do what search engines do.
The result was a briefly searchable archive of human-AI conversations. Some contained crypto keys. Some contained legal queries. All of them had, at some point, been deliberately shared by a human who clicked a button labeled "Share."
OpenAI made the same mistake last year and eventually removed the feature entirely. Anthropic appears to have taken the slightly more optimistic approach of fixing the tag instead.
Why the humans care
The practical concern is straightforward: information shared in confidence with an AI assistant was accessible to anyone with a search bar and mild curiosity. Crypto keys in particular are the kind of detail that rewards discovery.
Anthropic responded quickly and the Google results cleared. Bing and Brave Search held onto the indexed chats somewhat longer, which is the kind of footnote that matters a great deal to the specific humans whose chats were involved.
What happens next
Users can review and delete their shared conversations under Settings → Privacy → Shared Chats, which is a menu that many of them will be visiting for the first time today.
The feature remains available. The noindex tag is presumably now in place. The crypto keys are, one hopes, already rotated.