# Feedser OSV Connector – Operations Notes

_Last updated: 2025-10-16_

The OSV connector ingests advisories from OSV.dev across OSS ecosystems. This note highlights the additional merge/export expectations introduced with the canonical metric fallback work in Sprint 4.

## 1. Canonical metric fallbacks
- When OSV omits CVSS vectors (common for CVSS v4-only payloads) the mapper now emits a deterministic canonical metric id in the form `osv:severity/<level>` and normalises the advisory severity to the same `<level>`.
- Metric: `osv.map.canonical_metric_fallbacks` (counter) with tags `severity`, `canonical_metric_id`, `ecosystem`, `reason=no_cvss`. Watch this alongside merge parity dashboards to catch spikes where OSV publishes severity-only advisories.
- Merge precedence still prefers GHSA over OSV; the shared severity-based canonical id keeps Merge/export parity deterministic even when only OSV supplies severity data.

## 2. CWE provenance
- `database_specific.cwe_ids` now populates provenance decision reasons for every mapped weakness. Expect `decisionReason="database_specific.cwe_ids"` on OSV weakness provenance and confirm exporters preserve the value.
- If OSV ever attaches `database_specific.cwe_notes`, the connector will surface the joined note string in `decisionReason` instead of the default marker.

## 3. Dashboards & alerts
- Extend existing merge dashboards with the new counter:
  - Overlay `sum(osv.map.canonical_metric_fallbacks{ecosystem=~".+"})` with Merge severity overrides to confirm fallback advisories are reconciling cleanly.
  - Alert when the 1-hour sum exceeds 50 for any ecosystem; baseline volume is currently <5 per day (mostly GHSA mirrors emitting CVSS v4 only).
- Exporters already surface `canonicalMetricId`; no schema change is required, but ORAS/Trivy bundles should be spot-checked after deploying the connector update.

## 4. Runbook updates
- Fixture parity suites (`osv-ghsa.*`) now assert the fallback id and provenance notes. Regenerate via `dotnet test src/StellaOps.Feedser.Source.Osv.Tests/StellaOps.Feedser.Source.Osv.Tests.csproj`.
- When investigating merge severity conflicts, include the fallback counter and confirm OSV advisories carry the expected `osv:severity/<level>` id before raising connector bugs.
