> ## Documentation Index
> Fetch the complete documentation index at: https://docs.platform.nora.my/llms.txt
> Use this file to discover all available pages before exploring further.

# Forgetting

> Nothing is permanent unless you say so — TTLs, decay, and safe supersede.

Memory that never forgets becomes memory you can't trust. Nora exposes several ways to remove information — some automatic, some manual, all reversible where practical.

## Four ways things leave memory

### TTL (time-to-live)

Every memory item can have a TTL. When the clock runs out, the item is dropped.

Set at write time:

* Auto — new items get the space's default TTL.
* Explicit — the Agent (or your code) sets a per-item TTL. Common patterns:
  * Session summaries: 24 hours.
  * Temporary preferences: 30 days.
  * Facts with an expiration date: TTL = date.

Items with no TTL persist indefinitely (subject to importance decay, below).

### Importance decay

Every read updates an item's **importance-weighted use score**. Items not retrieved for a long time decay. When importance drops below a threshold, the item is quietly retired.

Decay rate is configurable per space. Turn off entirely (**Retention = permanent**) for glossaries and reference notes that should stay regardless of use.

### Manual supersede

Right-click any note → **Supersede**. Like knowledge supersede, the item is hidden from retrieval but retained for audit. Fully reversible.

Common cases:

* Fact was wrong — supersede and write a corrected version.
* Preference changed — supersede the old preference, let the Agent write the new one.

### Hard delete

For GDPR erasure, PII takedowns, or legal orders. Permanent.

Two flavors:

* **Delete item** — one specific item.
* **Delete scope** — every item under a scope key. Useful for "delete everything I know about user X".

Deletion is irreversible. There's a 7-day soft-delete window (item marked for deletion, hidden immediately, physically removed after grace) so accidental deletes can be undone.

## Auto-forgetting cadence

By default, Nora runs a nightly forgetting pass per space:

* Drops expired TTL items.
* Runs decay on importance scores.
* Hard-deletes items past their soft-delete grace.

Configurable per space. Turn off for spaces where you want tight control (compliance, high-stakes memory).

## Compliance

The **User data export** and **User data deletion** endpoints (documented in [Compliance](/settings/data/compliance)) walk every memory space and produce or delete all items matching a scope. Meets GDPR/CCPA erasure requirements.

Audit log: every deletion is logged with actor, timestamp, item ID, and reason. Retained separately from the memory itself.

## Reasons the Agent might "forget" without you deleting anything

Not every disappearing memory is deletion:

* **Consolidation** merged multiple notes into one (the content is preserved, but under a different item).
* **Scope changed** at runtime, and the memory is now invisible from the current scope.
* **Filter changed** on the memory attachment, and the item no longer matches.

Check the Trace's memory ops when investigating "the Agent used to know this — why doesn't it anymore?"