Snapshot
Status: Design / Planning Source: N/A (cross-cutting concept) Owner: Platform Team Audience: Platform and module engineers implementing or consuming point-in-time data captures.
Purpose
A snapshot is a deterministic, point-in-time capture of Stella Ops knowledge — advisories, VEX, SBOMs, policies, and task packs — taken so that an evaluation can be reproduced exactly later or moved across an air gap. Snapshots underpin four capabilities: offline operation, merge preview, deterministic replay, and air-gap export, each backed by cryptographic integrity (content digests and optional DSSE signatures).
This page is the entry point for the snapshot concept. The two companion documents below specify the concrete contracts.
Companion documents
| Document | Specifies |
|---|---|
| Merge Preview | How VEX statements from different sources combine via lattice logic, and the preview contract analysts use to inspect the result. |
| REPLAY.yaml Manifest | The manifest format and bundle layout that make an evaluation reproducible. |
Snapshot types
A snapshot bundle can capture any of the following data planes:
- Advisory snapshots — Concelier ingestion state
- VEX snapshots — VexHub distribution state
- SBOM snapshots — SbomService repository state
- Policy snapshots — Policy Engine rule state
- Task pack snapshots — PacksRegistry versions
Implementation locations
Snapshot functionality spans several modules:
| Module | Role |
|---|---|
| AirGap | Snapshot export/import orchestration |
| ExportCenter | Snapshot bundle creation and packaging |
| Replay | Deterministic replay from snapshots |
| Concelier | Advisory snapshot merge preview |
| All data modules | Snapshot sources |