Agent Operations
Fail-Open vs Fail-Closed
Also: fail open, fail closed
What a control does when it cannot work: fail-open lets the action through, fail-closed blocks it.
In more detail
A policy that cannot be loaded, has expired or is invalid forces a choice. Failing open keeps people working but leaves a gap; failing closed is safer but can stop work entirely. Neither is always right, so find out which way each of your controls fails and include a missing-policy case in your threat model.