PERMISSIONS AND ACCESS CONTROL

CHAPTER SUMMARY A permission resolver decides allow, deny, or ask for every request, checking deny rules first and defaulting to deny when nothing matches. Least privilege limits the blast radius by granting only the minimum access, scoped narrowly and kept short-lived. Allow-lists are generally stronger than deny-lists, and human approval should be triggered by the action's risk, not the agent's confidence. Secrets must stay out of the model's context and logs, with the harness injecting them at the last moment and a plan ready for rotation and incident response. KEY TERMS REVIEW Access control: deciding who or what may do which things. Permission resolver: the component that decides whether an action is allowed. Default deny: forbidding anything not explicitly permitted. Least privilege: granting only the minimum access needed. Blast radius: the area that can be damaged if something goes wrong. Allow-list: a list of the only permitted things. Deny-list: a list of forbidden things. Authentication: proving identity. Authorization: deciding what an identity may do. Secret: a private value that grants access. Key rotation: regularly replacing keys.