Claude Fable 5.1 can hide secret messages in images, and other AIs can read them
Researchers asked Claude Fable 5.1 to hide a secret sentence inside an ordinary picture. A brand new Fable session, given only a screenshot and no agreed code, read back 78 percent of the messages. GPT-6 Astra did even better at reading them. Here is how the trick works, why it matters for AI safety, and where the limits are.