{"id":"chat-monotonic-read-progress","text":"Chat combines per-conversation sequence numbers with monotonic read cursors, guaranteeing that once a message is marked read, no earlier message in that conversation can regress to unread.","truth_value":"IN","source":"","source_url":"","source_hash":"","justifications":[{"type":"SL","antecedents":["chat-dual-ordering-sequence-and-lamport","chat-read-cursors-monotonic"],"outlist":[],"label":"Sequence-number ordering + monotonic cursors create an irreversible read-progress guarantee"}],"dependents":["state-ratchets-prevent-regression-across-domains"],"metadata":{"last_reviewed":"2026-06-05T18:21:49","review_result":"pass"},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"chat-monotonic-read-progress","truth_value":"IN","reason":"SL justification valid","antecedents":["chat-dual-ordering-sequence-and-lamport","chat-read-cursors-monotonic"],"label":"Sequence-number ordering + monotonic cursors create an irreversible read-progress guarantee"},{"node":"chat-dual-ordering-sequence-and-lamport","truth_value":"IN","reason":"premise"},{"node":"chat-read-cursors-monotonic","truth_value":"IN","reason":"premise"}]}}