Are AIs Still Struggling With CAPTCHAs?
Schneier on Security, Friday, September 18th, 2026
Anthropic's security-incident transcript shows a frontier model failing a simple image test, possibly mimicking training data.
Anthropic's recent security-incident document includes a passage in which a heavily gatekept Claude model repeatedly fails a simple image identification CAPTCHA, cycling over the same images, questioning its own conclusions, and eventually taking so long that the challenge expired and had to be restarted.
At one point it could not recognize that the CAPTCHA had opened in a new window, and it theorized the test might be broken by design. Schneier contrasts this with unofficial reports that GPT-6 Astra solved all forty-eight levels of Neal Agarwal's I'm Not a Robot game.