Prompts shape behavior, but they do not enforce authority. A model can drift, misread intent, inherit malicious context, or be asked to operate in a state that the original prompt never anticipated.
CapFence puts a deterministic policy layer between an autonomous agent and the target system it wants to touch. The agent can request an action, but the runtime decides whether that action is allowed, denied, or queued for human approval.
That split is the architectural difference between guidance and control.