Agentic AI Harnesses: The layer above the model

Australia's cyber security agency published a definitional guide arguing that an agentic AI system's harness, the software layer connecting a language model to tools, data and memory, is where an organization's real security and governance work happens. "If you think of the LLM as the brain, then the harness is the body," the guide states. It lists eleven components of a harness that make up an organization's actual configuration surface, from the tool registry to the permission system, and recommends isolating exploratory work in sub-agents that get only the access a bounded task needs, deleting stale context instead of summarizing it, and monitoring API spend as a defense against what the guide calls "denial-of-wallet" attacks.

Why it matters: A national cyber security agency treating the harness, not the model, as the thing worth auditing gives practitioners a citable government source for making the same argument inside their own organizations.