id-drift

id-drift — the recurring drift sentinel (infra-delivery, post-spine)

The infra-delivery step sequence (a documented procedure this skill family forms — no workflow engine or state-machine file ships) drives an infra change → merge. After that spine, id-drift is the recurring step — a forever drift sentinel that re-runs the empty-plan seam (tofu plan == ∅) on a cadence (continuous and/or scheduled) to compare reality vs the merged IaC. It is the cadence-generalization of id-baseline: id-baseline proves drift-free once (at adoption); id-drift proves it forever (on every tick). The empty plan doubles as the forever drift check.

To detect drift it runs a read-only tofu plan — the active stack profile's infra_binding.plan command. It then reads the per-resource plan delta from the BUILT canonical parser foundry_plan_model.parse_actions_detail and frames the result:

• The empty-plan seam (tofu plan == ∅, actions_detail == []) ⇒ DRIFT-FREE — reality equals the merged IaC.
• The DRIFT (non-empty-plan) branch (actions_detail != []) ⇒ DRIFT — surface the diverging resources (the parse_actions_detail per-resource actions_detail) and hand them to id-sync/id-rollback (the reconcile/revert consumers).

It NEVER auto-reconciles — detection is read-only; the operator (via id-sync/id-rollback) decides the fix. The same empty-plan predicate id-baseline/id-import accept on is REUSED — not a new bar.

The cadence/schedule itself is the native scheduler's concern (a wrap, like the learn-distill tick); id-drift is the per-tick PROCEDURE the schedule fires.

ADVISORY — not a gate, no machine-adjudicated GREEN verdict

This skill is ADVISORY. It produces a drift report + a .foundry/-partitioned drift step-report note; it does NOT gate, approve, or block any merge. id-drift OBSERVES drift recurringly — it is not a change being delivered through a merge process — so it does NOT claim a machine-adjudicated GREEN verdict (mirroring id-baseline/id-verify, which observe and are not-self-certified). The empty-plan-vs-DRIFT branch is an advisory read, not a frozen verdict: it frames a non-empty parse_actions_detail result as DRIFT — surfaced as an observation, never a machine-adjudicated GREEN. The both-modes floor is unchanged: front-authorization, the merge floor (the adopter's branch protection + CI checks — see docs/merge-floor.md) remains the merge authority, security review, typed contracts.