Time-Aware Ranking

Temporal scoring

After retrieval and optional reranking, Aletheia applies temporal policy. Expired memories are filtered; surviving memories can be decayed based on age and kind.

This reduces stale recall while preserving long-lived facts and preferences.

TTL and decay

• TTL is a hard cutoff.
• Decay is a soft demotion.
• Policy is kind-specific, not global.

final_score = relevance_score * freshness_weight(kind, age)
if age > ttl(kind): drop

Practical tuning

Tune using replay datasets with known truth changes. If historical facts still outrank new facts, shorten half-life for conversational memory or increase supersession penalty.