For nearly three decades, the robots.txt file has served as the internet’s “Keep Out” sign. It is a binary, blunt instrument: Allow or Disallow. Crawlers either respect it or they don’t. However, as we enter the age of the Agentic Web, this binary distinction is no longer sufficient. We need a protocol that can express nuance, permissions, licenses, and economic terms. We need CATS (Content Authorization & Transparency Standard), often implemented as cats.txt or authorized_agents.json.