Evidence & retention policy

What we store, where we store it, and how we keep inspection continuous.

Every inspection outcome must be traceable to the artifacts and context that produced it.

Evidence tiers

Evidence tier	Stored	Retention	Location
Always (all events)	Metadata JSON: event_id, timestamp, station, SKU, verdict, confidence, model version	Indefinite	Edge DB
FAIL + REVIEW events	Defect frame(s), boxes, detection JSON, rule results, audit log	90 days local, then archive	Edge → Site object store
RCA events	Causal triple: defect + cause + action + outcome + operator disposition	Indefinite	Edge → Site DB
Optional raw video	Rolling ring buffer	7 days (overwrite)	Edge NVMe

Continuity rule

Storage pressure must never prevent defect metadata from being recorded.

Audit rule

If an outcome is reviewed later, it must have:

• an immutable event_id.

• the model version and config fingerprint.

• enough evidence artifacts to justify the verdict.