A behavioral boundary is a runtime control that limits what an AI agent can access, disclose, or do while operating. It can restrict which tools or data the agent may reach, what information it may return, and which actions it may execute. Unlike a prompt instruction, the boundary is enforced by system controls rather than relying on the model to follow directions.
These limits matter because an agent may have credentials and connections across multiple services. If its authority is too broad, misuse or manipulation could expose sensitive information or enable unauthorized actions. Practical defenses include least-privilege permissions, short-lived credentials, downstream authorization checks, and monitoring tool calls. Together, these controls help keep an agent within its intended scope and make unexpected behavior easier to detect and stop.