Your Agent's Memory Needs Two Clocks
Somewhere in your agent's memory store sits a fact like "the billing API returns XML." It reads as timeless truth. But it is actually two claims welded together: the API returned XML during some window of the past, and your agent observed this at some moment — possibly a different window, possibly long after the migration to JSON. The memory record keeps neither timestamp. When the agent acts on that fact and breaks something, you will ask the only question that matters in a post-incident review: what did the agent believe at the moment it acted? And your memory layer, having collapsed both timelines into one flat string, cannot answer.
Database engineers solved this problem decades ago and gave it an unglamorous name: bitemporal modeling. Every fact carries two independent clocks — when it was true in the world (valid time) and when the system learned it (transaction time). Financial systems, insurance ledgers, and audit-grade databases have run on this distinction for years. Agent memory systems, almost universally, ignore it. That omission is now the root cause of a whole family of failures we keep misdiagnosing as "hallucination."
