Policy Simulation Gaps (PS1–PS10) — Lockfile, Quotas, and Shadow Safety

Audience: Stella Ops developers wiring policy-simulation replay into CI and the Replay/EvidenceLocker pipeline. Scope: Closes POLICY-GAPS-185-006 by defining a signed inputs lock, an offline verifier, and shadow-isolation guardrails so policy simulations stay deterministic, read-only, and air-gap friendly.

Related guides: Replay Manifest Guide · Deterministic Replay Specification · Test Strategy. For the Replay module overview, see the module README.

Lockfile

Schema: docs/modules/replay/schemas/policy-sim/lock.schema.json
Sample: docs/modules/replay/samples/policy-sim/inputs.lock.sample.json
Fields cover policy bundle, graph, SBOM, time anchor, dataset digests; shadowIsolation flag; requiredScopes.
Recommended signing: DSSE over the lockfile with Ed25519; record envelope digest alongside artefacts.

Validation

Library helper: PolicySimulationInputLockValidator in StellaOps.Replay.Core compares materialized digests and enforces shadow mode + scope policy:simulate:shadow.
Staleness: pass maxAge (suggested 24h) to reject outdated locks.

CLI / CI contract

Script: scripts/replay/verify-policy-sim-lock.sh (offline). Exit codes: 0 OK, 2 missing tools/args, 3 schema/hash mismatch, 4 stale, 5 shadow/scope failure.
CI should run verifier before simulations and fail fast on non-zero exit.

Quotas & backpressure

Default limits: max 10 concurrent shadow runs per tenant; queue depth 100; reject when policy:simulate:shadow scope missing.
Simulators must be read-only: no writes to policy stores; only emit shadow metrics.

Offline policy-sim kit

Lockfile + DSSE, digests of policy/graph/sbom/time-anchor/dataset.
Bundle alongside replay packs; verifier uses local SHA256 only (no network).

Shadow isolation & redaction

Always run in shadow mode; block if requested runMode != shadow.
Redact PII fields (user, ip, headers, secrets) before storing fixtures; keep only hashes.
Require DSSE evidence when storing fixtures or responding to API clients.