Definition
Plain language
The little puzzle a website shows you to prove you're not a robot.
As stated in the literature
A challenge-response test designed to distinguish humans from automated agents, increasingly a failure mode for web-browsing AI agents.
Also called: CAPTCHA
Why it matters: Captchas are increasingly the bottleneck that determines whether a browser agent can actually finish a real task on the web.
For example, an AI shopping agent might get all the way to checkout and then be stopped by a 'click all images with bicycles' captcha.
Heard on the show
“It's whether it survives a captcha, an expired login, a fingerprint prompt on the payment screen — all the junk that never shows up in the lab.”Episode 189 — Why Phone Agents Ace the Test and Crash on Your Actual Phone