Summary

The recipe-evidence drift gate (ADR-007, docs/design/007-recipe-evidence.md) went live as a warning-only pilot. Real PR traffic — #1418 (aws-efa registry bump) and #1427 (re-sign of the two recipes that carry pointers) — surfaced three tunable rough edges and a contributor DevX blocker. This epic tracks tuning the pilot into something low-noise and easy to contribute to.

Context

• chore(recipes): bump aws-efa to v0.5.29, align image tag to appVersion #1418 changed a single registry entry (aws-efa) but the gate promoted ~all leaf recipes to "affected," producing an alarming warning list (despite being warning-only).
• chore(evidence): refresh gb200-eks + h100-gke-cos attestations #1427 re-signed the only two recipes that carry committed pointers (gb200-eks-ubuntu-training, h100-gke-cos-training); the gate then reported them "invalid" because it got an HTTP 403 pulling the evidence bundle from a contributor fork's (private) container registry — a cause that was not discoverable from the logs or the table.
• Sigstore keyless signing from a laptop is blocked on corporate VPN and some home networks (upstream Fulcio IP-level rejection), forcing contributors onto a phone hotspot.

The gate is warning-only and never blocks merge — this epic is pilot tuning, not a correctness fix.

Child issues

• Evidence gate: curated 'protected recipes' set (implicit by committed pointer) #1432 — Curated "protected recipes" set (implicit: has a committed pointer)
• Fork-based evidence signing workflow driven by committed unsigned pointers #1433 — Fork-based evidence signing workflow, driven by committed unsigned pointers
• aicr evidence: two-phase push-without-sign + sign-existing support #1434 — aicr evidence: two-phase push-without-sign + sign-existing support
• Evidence gate: scope registry/component cascade to actually-affected recipes #1435 — Scope registry/component cascade to actually-affected recipes
• Docs: Sigstore/Fulcio network blocking + recommended evidence publishing path #1436 — Docs: Sigstore/Fulcio network blocking + recommended publishing path
• Evidence gate: surface underlying verify failure cause (e.g. registry 403) #1437 — Surface the underlying verify failure cause (e.g. registry 403)