---
title: "What is point-in-time recall in agent memory?"
description: "Point-in-time recall returns what was true, or what was known, as of a chosen date. Definition, the queries it answers, and how temporal storage makes it possible."
canonical: https://past.dev/glossary/point-in-time-recall
last-updated: 2026-10-15
---
# Point-in-time recall

Source: https://past.dev/glossary/point-in-time-recall

Point-in-time recall evaluates a memory query at a specified date. A question about the delivery date on March 3 uses facts whose validity windows covered March 3. The storage layer must retain superseded facts and their validity periods. Overwriting a value removes the data required for this query.

## The queries point-in-time recall answers

- **Reconstruction.** What did the account look like on the day of the incident. Asked in support escalations, disputes and audits.
- **Decision review.** What information was current when a decision was made.
- **Change tracing.** When did the value change, and what did it change from. The difference between two point-in-time answers.

## What the storage layer must provide

The storage layer needs three properties. Facts carry [validity windows](/glossary/validity-window). Updates close previous windows through [fact supersession](/glossary/fact-supersession). Ingestion preserves original timestamps for backfilled history. Point-in-time recall can then filter facts by window coverage.

## Point-in-time recall in past.dev

past.dev recall accepts an optional `queryTimestamp` and returns ranked documents with occurrence dates and source excerpts. The application can use those public fields for current or historical questions.

See the [quickstart](/docs/memory-api/quickstart) for backdated ingestion and the [benchmarks page](/benchmarks) for how historical queries are evaluated.

## Common failure modes without it

- An agent cites today's policy against last quarter's order, because only the current policy exists in the store.
- A support reconstruction shows the corrected record and hides what the customer actually saw at the time.
- A backfill stamps last year's facts with this week's date, and every as-of answer silently shifts.

## Frequently asked questions

### Is point-in-time recall the same as version history?

Version history stores snapshots of documents. Point-in-time recall answers questions over facts, which may be assembled from many documents. The fact layer makes the as-of answer directly queryable instead of manually reconstructable from diffs.

### Does point-in-time recall cost more to store?

It retains superseded facts, so storage grows with the number of changes. This additional storage preserves the data required for historical queries.

## Related

- [Bitemporal memory](https://past.dev/glossary/bitemporal-memory)
- [Validity window](https://past.dev/glossary/validity-window)
- [Temporal knowledge graph](https://past.dev/glossary/temporal-knowledge-graph)
- [What is agent memory?](https://past.dev/what-is-agent-memory)
- [Quickstart](https://past.dev/docs/memory-api/quickstart)