The vendor manifest ([the vendoring decision](../../implemented/process/2026-06-11-vendor-cordis-as-source.md)) is enforced at commit time in the *forward* direction (vendored change ⇒ manifest update) but nothing verifies the manifest's *claims*: that vendor/ actually equals upstream-at-SHA plus exactly the logged modifications. And the handful of true npm dependencies have no advisory monitoring or update cadence.
1.**Vendor drift check** (nightly CI): clone the upstream repos at the manifest SHAs (shallow), copy the corresponding package sources, and diff against `vendor/*/src`. The job fails unless the diff matches the logged local modifications (kept as a checked-in patch file per modification — the log entries become verifiable artifacts rather than prose).
3.**License inventory**: a script asserting every vendored package carries its LICENSE and that package.json `license` fields match the inventory in vendor/README.md (we mix vendored MIT with our BSD-3) — CI step.
4.**Renovate** (or a scheduled agent task) proposing npm dependency updates in small PRs that ride the full gate suite; vendored packages are excluded (their updates follow the manifest sync procedure, ideally as a semi-automated agent workflow: fetch upstream, re-apply patches, run gates, open PR with the manifest table updated).
3 is trivial — do first. 1 requires network access from CI to the upstream repos (private — needs a token) and converting the two existing logged modifications into patch files. 2 and 4 are config.
Upstream repos are private mirrors; CI credentials and availability are the main friction for the drift check. If blocked, run it as a local scheduled agent task instead of CI.
