{"id":"message-delivery-guarantees-are-consumer-side","text":"Message queue delivery guarantees (at-least-once, at-most-once, exactly-once) are enforced entirely at the consumer layer through poll/commit semantics and the two-tier offset mechanism (current vs committed), making the broker stateless with respect to delivery semantics and pushing guarantee selection to the consumer.","truth_value":"IN","source":"","source_url":"","source_hash":"","justifications":[{"type":"SL","antecedents":["dmq-delivery-semantics-in-poll","dmq-two-tier-offset-tracking"],"outlist":[],"label":"The two-tier offset gap (current minus committed) is the mechanism that enables all three delivery modes — the broker just stores offsets, consumers choose semantics"}],"dependents":["delivery-guarantees-follow-write-read-cost-asymmetry","queue-abstraction-is-logical-not-physical"],"metadata":{"last_reviewed":"2026-06-06T06:26:57","review_result":"pass"},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"message-delivery-guarantees-are-consumer-side","truth_value":"IN","reason":"SL justification valid","antecedents":["dmq-delivery-semantics-in-poll","dmq-two-tier-offset-tracking"],"label":"The two-tier offset gap (current minus committed) is the mechanism that enables all three delivery modes — the broker just stores offsets, consumers choose semantics"},{"node":"dmq-delivery-semantics-in-poll","truth_value":"IN","reason":"premise"},{"node":"dmq-two-tier-offset-tracking","truth_value":"IN","reason":"premise"}]}}