Rate limits were designed for predictable clients with humans behind the screen. But AI agents act differently. They make decisions, call APIs, and post content without understanding context. Harm limiting is an emerging approach that focuses on how data is used after it leaves the API. It adds structure and guidance to help models act more responsibly and gives developers a clearer way to manage risk as AI systems become more autonomous. The traditional safeguards of rate limits and basic authentication are no longer enough in an ecosystem shaped by autonomous agents. Harm limiting builds on traditional API infrastructure by introducing a way to guide how data is used, not just whether or how often it's accessed.