Abstention
Abstention is the system choosing not to provide a substantive answer when it lacks sufficient evidence, permission, or confidence.
Tiny example
Section titled “Tiny example”If retrieval finds no policy for a requested country, a useful response is “I cannot verify that from the available policy documents” plus an escalation path—not an invented universal policy.
Why it matters
Section titled “Why it matters”A system that answers every question can look helpful while failing dangerously on unanswerable cases.
FDE note
Section titled “FDE note”Include answerable and unanswerable cases in evaluation. Track both false answers and unnecessary refusals, then set the decision threshold according to the cost of each failure.