deepseek-harness/.agents/notes/proposed/process/2026-06-11-supply-chain-and-vendor-drift.md

Agent Note: Supply chain checks and vendor drift verification

Status: proposed

Problem

The vendor manifest (the vendoring decision) 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.

Proposal

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).
2. Dependency advisories: osv-scanner (or pnpm audit) job on the lockfile, scheduled + on lockfile-touching PRs.
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).

Plan

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.

Alternatives considered

• pnpm audit instead of osv-scanner — either satisfies the advisory-scanning shape; the choice is deferred to implementation.
• A scheduled agent task instead of Renovate — equivalent for proposing small update PRs that ride the full gate suite; vendored packages stay excluded either way (their updates follow the manifest sync procedure).

Acceptance criteria

• The license inventory script runs in CI and fails on a missing LICENSE or a license field that contradicts the inventory in vendor/README.md.
• The nightly drift job reconstructs vendor/ from the manifest SHAs plus checked-in patch files and fails on any unexplained diff.
• Advisory scanning runs on the lockfile on schedule and on lockfile-touching PRs.

Risks

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.