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

# Memory release lifecycle

> The candidate state machine, evidence gate, promotion protocol, and forward-only rollback model.

Stash treats durable memory as a release artifact. A candidate is immutable input to a state machine; a memory version is the released result of an approved candidate.

```mermaid theme={"system"}
stateDiagram-v2
  [*] --> proposed
  proposed --> screening: begin_screening
  proposed --> quarantined: quarantine
  proposed --> rejected: reject
  screening --> evaluating: screening_passed / begin_evaluation
  screening --> quarantined: quarantine
  screening --> rejected: reject
  screening --> failed: provider_failed
  evaluating --> review_required: evaluation_passed / request_review
  evaluating --> quarantined: quarantine
  evaluating --> rejected: reject
  evaluating --> failed: provider_failed
  review_required --> approved: approve
  review_required --> rejected: reject
  review_required --> quarantined: quarantine
  approved --> active: activate
  approved --> rejected: reject
  active --> superseded: supersede
  active --> rolled_back: roll_back
  active --> expired: expire
```

## Evidence before authority

Screening checks deterministic risk and source rules. Evaluation binds results to the candidate and the baseline namespace revision. Review then binds the candidate digest, evaluation run, baseline revision, and policy version. Promotion rejects a stale or mismatched review.

## One active version per lineage

The database enforces one active version for each tenant and lineage. Promotion deactivates the previous version, creates the next version, advances the namespace revision, and records the activation and audit events transactionally.

## Rollback moves forward

Rollback does not reactivate a row in place or delete an unsafe release. It creates a new memory version and a new namespace revision using a prior payload. This preserves what agents saw, who changed it, and why the system moved back.

For lookup-oriented details, see [lifecycle states](/reference/lifecycle-states). For operational steps, see [how to roll back a lineage](/guides/rollback-lineage).