diff --git a/INTENT.md b/INTENT.md
index 6ad79e0..ff26ce2 100644
--- a/INTENT.md
+++ b/INTENT.md
@@ -306,27 +306,27 @@ policy service consumer-specific.
 
 ## Layer Conformance
 
-flex-auth's conformance state under §11 is **conforming with one declared gap**.
-It holds no Tooling client, so the §5 shapes do not apply to it, and it is not
-PEP-shaped, so it owes no stance map under §6.4.
+flex-auth's conformance state under §11 is **conforming**. The mechanical
+check is `go run ./tools/check_layer_conformance.go` (wired into `make test`):
+the INTENT.md declaration parses, the layer is in the §3 vocabulary, the
+Engine role is PDP, and no Tooling client exists in production Go sources.
+It is not PEP-shaped, so it owes no stance map under §6.4.
 
-**The declared gap — registry-snapshot digest in decision provenance (§13).**
-`DecisionProvenance` carries the evaluator, mode, policy package, policy version,
-directory ETag, and decision time, but no digest of the registry snapshot that
-supplied resource, subject, and relationship facts. A decision that turned on
-registry content cannot be replayed from its own provenance.
+The former declared gap — registry-snapshot digest in decision provenance —
+is closed. `DecisionProvenance` carries `registry_snapshot_digest` so a
+decision that turned on registry content is replayable from its own record.
+Revocation visibility deadlines per input class are stated in
+[`docs/decision-input-freshness.md`](docs/decision-input-freshness.md).
+The published decision-record contract is
+[`docs/decision-record-contract.md`](docs/decision-record-contract.md)
+(`flex-auth.decision-record.v1`). The §6.4.2 replay test is
+[`docs/canonical-request-digest.md`](docs/canonical-request-digest.md).
 
-v0.7 §9.7.2 promotes this from housekeeping to a **conformance prerequisite**,
-on flex-auth's own argument: a stated visibility deadline for a fact carried by
-a registry snapshot is unfalsifiable while provenance holds no snapshot digest,
-because nobody can determine afterwards which snapshot a decision read. The
-deadline and the digest are one gap seen from two sides.
-
-Until it closes, one rule holds and flex-auth applies it to everyone equally,
-including itself: **outcome-determining content belongs in the versioned policy
-package, not in registry content** — for zone stance, for gate-house's authority
+Outcome-determining content still belongs in the versioned policy package,
+not in registry content — for zone stance, for gate-house's authority
 ceilings, for maturity levels, and for flex-auth's own facts. Registry content
-carries membership and identity; the policy package carries effect.
+carries membership and identity; the policy package carries effect. The
+snapshot digest makes that split checkable rather than aspirational.
 
 ## Non-Goals
 
diff --git a/Makefile b/Makefile
index 3b85ced..9cc60b4 100644
--- a/Makefile
+++ b/Makefile
@@ -4,7 +4,7 @@ PKG     := ./...
 VERSION ?= $(shell git describe --tags --always --dirty 2>/dev/null || echo 0.0.0-dev)
 LDFLAGS := -X main.version=$(VERSION)
 
-.PHONY: all build test vet lint fmt tidy sbom clean ci overlay-render overlay-dry-run verify-posture
+.PHONY: all build test vet lint fmt tidy sbom clean ci overlay-render overlay-dry-run verify-posture check-layer
 
 all: vet lint test build
 
@@ -12,9 +12,12 @@ build:
 	@mkdir -p $(BIN_DIR)
 	go build -ldflags "$(LDFLAGS)" -o $(BIN) ./cmd/flex-auth
 
-test:
+test: check-layer
 	go test -race $(PKG)
 
+check-layer:
+	go run ./tools/check_layer_conformance.go
+
 vet:
 	go vet $(PKG)
 
diff --git a/WORK-RECORDS.md b/WORK-RECORDS.md
index c537d46..5bcff75 100644
--- a/WORK-RECORDS.md
+++ b/WORK-RECORDS.md
@@ -26,7 +26,7 @@
 | workplan | FLEX-WP-0016 | finished | — | workplans/FLEX-WP-0016-ops-warden-incluster-policy-pin.md |
 | workplan | FLEX-WP-0017 | finished | — | workplans/FLEX-WP-0017-action-bound-authorization-contract.md |
 | workplan | FLEX-WP-0018 | finished | — | workplans/FLEX-WP-0018-inbound-auth-corrections.md |
-| workplan | FLEX-WP-0019 | ready | — | workplans/FLEX-WP-0019-layer-model-conformance.md |
+| workplan | FLEX-WP-0019 | finished | — | workplans/FLEX-WP-0019-layer-model-conformance.md |
 | workplan | FLEX-WP-0020 | proposed | — | workplans/FLEX-WP-0020-repository-identity-migration.md |
 | task | FLEX-WP-0001-T001 | done | — | workplans/FLEX-WP-0001-repo-intent-and-architecture-baseline.md |
 | task | FLEX-WP-0001-T002 | done | — | workplans/FLEX-WP-0001-repo-intent-and-architecture-baseline.md |
@@ -109,12 +109,12 @@
 | task | FLEX-WP-0017-T05 | cancel | — | workplans/FLEX-WP-0017-action-bound-authorization-contract.md |
 | task | FLEX-WP-0018-T01 | done | — | workplans/FLEX-WP-0018-inbound-auth-corrections.md |
 | task | FLEX-WP-0018-T02 | done | — | workplans/FLEX-WP-0018-inbound-auth-corrections.md |
-| task | FLEX-WP-0019-T01 | todo | — | workplans/FLEX-WP-0019-layer-model-conformance.md |
-| task | FLEX-WP-0019-T02 | todo | — | workplans/FLEX-WP-0019-layer-model-conformance.md |
-| task | FLEX-WP-0019-T03 | todo | — | workplans/FLEX-WP-0019-layer-model-conformance.md |
-| task | FLEX-WP-0019-T04 | todo | — | workplans/FLEX-WP-0019-layer-model-conformance.md |
-| task | FLEX-WP-0019-T05 | todo | — | workplans/FLEX-WP-0019-layer-model-conformance.md |
-| task | FLEX-WP-0019-T06 | todo | — | workplans/FLEX-WP-0019-layer-model-conformance.md |
+| task | FLEX-WP-0019-T01 | done | — | workplans/FLEX-WP-0019-layer-model-conformance.md |
+| task | FLEX-WP-0019-T02 | done | — | workplans/FLEX-WP-0019-layer-model-conformance.md |
+| task | FLEX-WP-0019-T03 | done | — | workplans/FLEX-WP-0019-layer-model-conformance.md |
+| task | FLEX-WP-0019-T04 | done | — | workplans/FLEX-WP-0019-layer-model-conformance.md |
+| task | FLEX-WP-0019-T05 | done | — | workplans/FLEX-WP-0019-layer-model-conformance.md |
+| task | FLEX-WP-0019-T06 | done | — | workplans/FLEX-WP-0019-layer-model-conformance.md |
 | task | FLEX-WP-0020-T01 | todo | — | workplans/FLEX-WP-0020-repository-identity-migration.md |
 | task | FLEX-WP-0020-T02 | todo | — | workplans/FLEX-WP-0020-repository-identity-migration.md |
 | task | FLEX-WP-0020-T03 | todo | — | workplans/FLEX-WP-0020-repository-identity-migration.md |
diff --git a/docs/action-bound-authorization-contract.md b/docs/action-bound-authorization-contract.md
index 1945569..67b6800 100644
--- a/docs/action-bound-authorization-contract.md
+++ b/docs/action-bound-authorization-contract.md
@@ -16,8 +16,13 @@ POST /v1/check
 
 The response now includes `binding`, the exact normalized subject, action,
 resource, context, and full SHA-256 request digest evaluated by the policy.
-Consumers must compare structured fields; `reason`, `diagnostics`, titles, and
-other prose are never an authorization contract.
+How that digest is computed, what is excluded, and when replay is permitted
+are in [`canonical-request-digest.md`](canonical-request-digest.md). Consumers
+must compare structured fields; `reason`, `diagnostics`, titles, and other
+prose are never an authorization contract.
+
+The decision envelope itself is the published PDP contract
+[`decision-record-contract.md`](decision-record-contract.md).
 
 `approval-engine` owns the durable approval object, authenticated approval
 evidence, storage, supersession, consumption, and availability. State Hub
diff --git a/docs/canonical-request-digest.md b/docs/canonical-request-digest.md
new file mode 100644
index 0000000..eef035a
--- /dev/null
+++ b/docs/canonical-request-digest.md
@@ -0,0 +1,98 @@
+# Canonical request digest
+
+Status: published
+Date: 2026-09-02
+Standard: security-layer-model_v0.7 §6.4.2
+
+The digest is the mechanical test for replaying a flex-auth verdict. A consumer
+may reuse an allow **iff** a new request produces the same digest **and** the
+decision's lifetime still holds. Negative caching of a deny uses the same test.
+
+Constructor: `api.NewDecisionBinding` / `api.RequestDigest`.
+Field: `DecisionEnvelope.binding.request_digest`.
+Format: `sha256:` plus 64 lowercase hex characters.
+
+## What is hashed
+
+Canonical JSON (Go `encoding/json`, which sorts map keys) of:
+
+| Field | Source |
+| --- | --- |
+| `tenant` | `CheckRequest.tenant` |
+| `subject` | normalized `CheckRequest.subject` |
+| `action` | `CheckRequest.action` |
+| `resource` | normalized `CheckRequest.resource` |
+| `context` | `CheckRequest.context` |
+
+Empty optional maps and omitempty strings are omitted. Attribute maps inside
+subject and resource are part of the material once the evaluator has enriched
+them from the registry.
+
+**Not hashed:** `id`, `policy_version`, and `caring_context`. The request id is
+correlation only. Policy version is recorded in provenance. CARING context is
+hashed separately as `provenance.input_claim_digests.caring_context`.
+
+## Normalization
+
+1. Tenant on the request is copied onto subject and resource when those refs
+   omit it.
+2. A registry hit copies type, tenant, and selected attributes onto the refs
+   the digest sees.
+3. Context is a shallow copy. Key order is not significant.
+
+A consumer that re-hashes the **original** unenriched request will not match a
+decision that turned on registry attributes. Compare structured `binding`
+fields to the proposed action, and treat `request_digest` as the evaluator's
+statement of what it hashed. To recompute independently, hash the same
+normalized tuple the binding carries (tenant, subject, action, resource,
+context).
+
+## Stability
+
+The digest is stable across process restarts for the same normalized tuple.
+It is **not** stable across:
+
+- a change to any hashed field, including registry-enriched attributes
+- a change to this contract (would require a new `contract_version`)
+
+It does not include the policy package, snapshot, or clock. Those live in
+provenance and `lifetime`. Two allows over the same tuple but different
+snapshots share a digest and differ in `registry_snapshot_digest`.
+
+## Worked example — permitted retry
+
+Request (after enrichment):
+
+```json
+{
+  "tenant": "tenant:alpha",
+  "subject": {"id": "user:alice", "type": "Human", "tenant": "tenant:alpha"},
+  "action": "read",
+  "resource": {
+    "id": "document:internal-note",
+    "type": "document",
+    "system": "markitect-tool",
+    "tenant": "tenant:alpha"
+  },
+  "context": {"purpose": "project-delivery"}
+}
+```
+
+The evaluator stores `binding.request_digest` for that tuple and
+`lifetime.expires_at` in the future. The same subject, action, resource, and
+context presented again before expiry is a permitted retry of that allow.
+
+## Worked example — refused replay
+
+Any of the following refuses replay:
+
+- `action` changes from `read` to `destroy` (digest mismatch)
+- `resource.attributes.stage` changes from `build` to `production` (digest mismatch)
+- `lifetime.expires_at` is in the past (lifetime does not hold)
+- the stored effect is `deny` and the consumer is attempting to treat a cached
+  refusal as still binding after a policy change — negative cache is valid only
+  for the same digest **and** while the recorded lifetime would have held; a
+  new `Check` is required once either fails
+
+Local fixtures, State Hub `/decisions/{uuid}` records, and free-form
+`decided_by` values are not this test.
diff --git a/docs/decision-input-freshness.md b/docs/decision-input-freshness.md
new file mode 100644
index 0000000..2e4d3a8
--- /dev/null
+++ b/docs/decision-input-freshness.md
@@ -0,0 +1,72 @@
+# Decision input freshness
+
+Status: published
+Date: 2026-09-02
+Standard: security-layer-model_v0.7 §9.7.2
+
+A flex-auth decision is a join over sources that refresh independently. One
+number at a PDP would be either a fiction or the worst case. This document
+states a **visibility deadline per input class**, with the mechanism that
+bounds it.
+
+Provenance identifies which snapshot and package a decision read
+(`registry_snapshot_digest`, `policy_package_digest`, `directory_etag`,
+`input_claim_digests`). Without those digests a deadline is unfalsifiable.
+
+Operational bound shared by every class: an allow is never valid past
+`lifetime.expires_at` (default TTL 15m). That is the consumer-visible ceiling.
+The class deadlines below say when a **new Check** is guaranteed to see a
+revocation of that class of input.
+
+## Approval-claim freshness
+
+| | |
+| --- | --- |
+| What is joined | Request-time approval and identity claims on `CheckRequest.context` (and related subject attributes) |
+| Mechanism | No PDP-side cache of claims. Each Check evaluates the claims as presented. |
+| Deadline | **Immediate** on the next Check (0). A revoked claim is visible as soon as the consumer stops sending it. |
+| Cached allow | Bounded by `lifetime`. Replay of a previous allow after the claim is revoked is refused once the digest no longer matches or the TTL ends. |
+| Provenance | `input_claim_digests.context` |
+
+flex-auth does not store or mutate the approval object (`approval-engine`).
+
+## Registry snapshot cadence
+
+| | |
+| --- | --- |
+| What is joined | Protected systems, resources, subjects, groups, teams, tenants, relationship facts |
+| Mechanism | In-memory `registry.Store` loaded at process start and by `flex-auth load-registry`. There is no background watch. |
+| Deadline | A registry-borne revocation is visible after the operator reloads the snapshot **or** when the current allow TTL ends, whichever is first. On a running process that has not reloaded, the snapshot is otherwise unchanged. |
+| Provenance | `registry_snapshot_digest` — SHA-256 of canonical snapshot JSON |
+
+The digest makes the deadline checkable: a later Check whose digest differs
+read a different snapshot.
+
+## Policy package activation
+
+| | |
+| --- | --- |
+| What is joined | The validated Rego-in-Markdown package (`id` / `version` / compiled module) |
+| Mechanism | Loaded at process start and by CLI `--policy`. No hot swap. |
+| Deadline | A package change is visible after reload **or** when the current allow TTL ends, whichever is first. |
+| Provenance | `policy_package`, `policy_version`, `policy_package_digest` |
+
+## Directory ETag
+
+| | |
+| --- | --- |
+| What is joined | Delegated directory state (Topaz objects/relations, relationship-PDP tuples) and optional group-resolver evidence |
+| Mechanism | Topaz returns `DirectoryETag`; relationship adapters return a consistency token. Group resolvers (`Graph`, `SCIM`, `LDAP`, `Keycloak`) attach `Freshness.MaxAge` when configured. Verdicts are not cached by flex-auth. |
+| Deadline | **Next Check** against the directory for ETag-bearing adapters (0 relative to the directory's own visibility). For resolvers, the configured `MaxAge`; if `MaxAge` is unset, directory-borne group evidence is unbounded except by the allow TTL. |
+| Provenance | `directory_etag`; resolver freshness is subject-attribute evidence, not a second decision |
+
+A stale-directory signal from Topaz fails closed (`topaz_directory_stale`).
+
+## How to read this as a consumer
+
+1. Do not cache a verdict past `lifetime.expires_at`.
+2. To know whether a stored allow still names the same facts, compare
+   `registry_snapshot_digest`, `policy_package_digest`, and `directory_etag`
+   to a fresh Check.
+3. Approval revocation is a claim-class problem: stop presenting the claim,
+   and do not replay a digest that included it.
diff --git a/docs/decision-record-contract.md b/docs/decision-record-contract.md
new file mode 100644
index 0000000..ce6b3d0
--- /dev/null
+++ b/docs/decision-record-contract.md
@@ -0,0 +1,57 @@
+# Decision-record contract
+
+Status: published
+Contract: `flex-auth.decision-record.v1`
+Schema: [`../schemas/decision_envelope.schema.json`](../schemas/decision_envelope.schema.json)
+Date: 2026-09-02
+
+This is flex-auth's output artifact under the NetKingdom Security Layer Model
+v0.7 §17. Taxonomy holds only the shared field vocabulary. Consumers may rely
+on this schema.
+
+A decision record is a `DecisionEnvelope` returned by `POST /v1/check` and the
+CLI `check` / `batch-check` / `list-allowed` commands. Standalone evaluation
+and every delegated adapter (Topaz, relationship, rule, Keycloak) emit the
+same shape.
+
+## Required fields
+
+| Field | Meaning |
+| --- | --- |
+| `id` | Deterministic decision identifier |
+| `effect` | `allow`, `deny`, `redact`, `audit_only`, or `not_applicable` |
+| `subject` / `resource` | Normalized refs the evaluator used |
+| `provenance` | Who evaluated, over which policy and facts |
+
+## Contract fields consumers may rely on
+
+| Field | Meaning |
+| --- | --- |
+| `contract_version` | `flex-auth.decision-record.v1` |
+| `binding` | Structured subject, action, resource, context, and `request_digest` |
+| `lifetime` | **Required on every allow.** A TTL with `not_before` and `expires_at` |
+| `provenance.policy_package` / `policy_version` | Named package pin |
+| `provenance.policy_package_digest` | SHA-256 of package metadata plus compiled Rego |
+| `provenance.registry_snapshot_digest` | SHA-256 of the canonical registry snapshot |
+| `provenance.directory_etag` | Directory consistency token when a delegated directory was joined |
+| `provenance.input_claim_digests` | SHA-256 per request-time claim class (`context`, `caring_context`) |
+| `provenance.decision_time` | UTC timestamp used to compute `lifetime` |
+
+`reason`, `diagnostics`, and CARING prose are not an authorization contract.
+
+## Allow lifetime
+
+Every allow carries `lifetime.kind = ttl`. The duration comes from the policy
+package `allow_ttl` field, or from the engine default of `15m` when the package
+omits it. A package that declares `allow_ttl: none` (or `0s`) produces a deny
+with reason `allow_lifetime_unstated` instead of a standing grant.
+
+Replay is permitted only while `lifetime.expires_at` is still in the future.
+See [`canonical-request-digest.md`](canonical-request-digest.md) and
+[`decision-input-freshness.md`](decision-input-freshness.md).
+
+## Versioning
+
+This is contract version 1. Additive optional fields may appear. Removing or
+redefining a required field requires a new `contract_version` value and a new
+schema id.
diff --git a/examples/caring/action_authorization.json b/examples/caring/action_authorization.json
index 2abe187..50835f0 100644
--- a/examples/caring/action_authorization.json
+++ b/examples/caring/action_authorization.json
@@ -47,6 +47,7 @@
   },
   "decision": {
     "id": "decision:contract-example",
+    "contract_version": "flex-auth.decision-record.v1",
     "request_id": "check:secrets-engine-destroy-example",
     "effect": "allow",
     "reason": "destruction_approved",
@@ -87,7 +88,13 @@
       "context": {
         "purpose": "contract-test"
       },
-      "request_digest": "sha256:73d5d7d5b3363f1a1db8f4c0e79c8f33dae5d77ffb97f21e449438bc0defa4c3"
+      "request_digest": "sha256:eb9d856a060813aebe039f19b82d4be1c4589fa6c0429cf20e15fb115db3ef9a"
+    },
+    "lifetime": {
+      "kind": "ttl",
+      "ttl": "15m",
+      "not_before": "2026-08-23T10:00:30Z",
+      "expires_at": "2026-08-23T10:15:30Z"
     },
     "provenance": {
       "evaluator": "flex-auth/local",
diff --git a/examples/caring/decision_envelope.json b/examples/caring/decision_envelope.json
index 78b600f..e40ec4f 100644
--- a/examples/caring/decision_envelope.json
+++ b/examples/caring/decision_envelope.json
@@ -1,5 +1,6 @@
 {
   "id": "decision:tenant-alpha-internal-note",
+  "contract_version": "flex-auth.decision-record.v1",
   "request_id": "check:tenant-alpha-internal-note",
   "effect": "allow",
   "reason": "reader_relation",
@@ -33,7 +34,13 @@
     "context": {
       "purpose": "project-delivery"
     },
-    "request_digest": "sha256:76ddf09170fc5ac49fb58aa9a6f5fb25bf1eb68b969254553979eb1ee0f15fab"
+    "request_digest": "sha256:99f772642c55b232a2d2fd3d5ff223cf1bf2c4f68942cd0def7c02cd3e5ae6ae"
+  },
+  "lifetime": {
+    "kind": "ttl",
+    "ttl": "15m",
+    "not_before": "2026-05-17T00:00:00Z",
+    "expires_at": "2026-05-17T00:15:00Z"
   },
   "obligations": [
     {
@@ -51,6 +58,11 @@
     "mode": "standalone",
     "policy_package": "markitect.documents",
     "policy_version": "v1",
+    "policy_package_digest": "sha256:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+    "registry_snapshot_digest": "sha256:bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb",
+    "input_claim_digests": {
+      "context": "sha256:cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc"
+    },
     "decision_time": "2026-05-17T00:00:00Z"
   },
   "caring": {
diff --git a/internal/adapters/keycloak/adapter.go b/internal/adapters/keycloak/adapter.go
index 89d9871..5b517f7 100644
--- a/internal/adapters/keycloak/adapter.go
+++ b/internal/adapters/keycloak/adapter.go
@@ -13,11 +13,14 @@ import (
 // Adapter maps flex-auth checks and resources to Keycloak Authorization
 // Services while preserving the flex-auth decision envelope.
 type Adapter struct {
-	client        Client
-	realm         string
-	audience      string
-	policyPackage string
-	policyVersion string
+	client                 Client
+	realm                  string
+	audience               string
+	policyPackage          string
+	policyVersion          string
+	policyPackageDigest    string
+	registrySnapshotDigest string
+	allowTTL               string
 }
 
 func New(client Client, options Options) (*Adapter, error) {
@@ -31,11 +34,14 @@ func New(client Client, options Options) (*Adapter, error) {
 		return nil, fmt.Errorf("keycloak audience is required")
 	}
 	return &Adapter{
-		client:        client,
-		realm:         options.Realm,
-		audience:      options.Audience,
-		policyPackage: options.PolicyPackage,
-		policyVersion: options.PolicyVersion,
+		client:                 client,
+		realm:                  options.Realm,
+		audience:               options.Audience,
+		policyPackage:          options.PolicyPackage,
+		policyVersion:          options.PolicyVersion,
+		policyPackageDigest:    options.PolicyPackageDigest,
+		registrySnapshotDigest: options.RegistrySnapshotDigest,
+		allowTTL:               options.AllowTTL,
 	}, nil
 }
 
@@ -154,7 +160,8 @@ func (a *Adapter) envelope(request api.CheckRequest, authz AuthorizationRequest,
 		},
 		Caring: caringDecisionMetadata(firstDescriptor(request.CaringContext, result.CaringDescriptor), result.ConformanceFindings),
 	}
-	envelope.ID = decisionID(a.policyPackage, policyVersion, request, effect, reason)
+	envelope = a.finish(request, envelope)
+	envelope.ID = decisionID(a.policyPackage, policyVersion, request, envelope.Effect, envelope.Reason)
 	return envelope
 }
 
@@ -179,10 +186,22 @@ func (a *Adapter) failureEnvelope(request api.CheckRequest, authz AuthorizationR
 		},
 		Caring: caringDecisionMetadata(request.CaringContext, []api.CaringConformanceFinding{failureFinding(kind)}),
 	}
+	envelope = a.finish(request, envelope)
 	envelope.ID = decisionID(a.policyPackage, policyVersion, request, envelope.Effect, envelope.Reason)
 	return envelope
 }
 
+func (a *Adapter) finish(request api.CheckRequest, envelope api.DecisionEnvelope) api.DecisionEnvelope {
+	if envelope.Provenance.RegistrySnapshotDigest == "" {
+		envelope.Provenance.RegistrySnapshotDigest = a.registrySnapshotDigest
+	}
+	if envelope.Provenance.PolicyPackageDigest == "" {
+		envelope.Provenance.PolicyPackageDigest = a.policyPackageDigest
+	}
+	api.CompleteDecision(&envelope, request, api.DecisionCompletion{AllowTTL: a.allowTTL})
+	return envelope
+}
+
 func caringDecisionMetadata(descriptor *api.CaringAccessDescriptor, findings []api.CaringConformanceFinding) *api.CaringDecisionMetadata {
 	profile := api.CaringProfileCaring040RC2
 	if descriptor != nil && descriptor.Profile != "" {
diff --git a/internal/adapters/keycloak/types.go b/internal/adapters/keycloak/types.go
index 59e4ddf..1172901 100644
--- a/internal/adapters/keycloak/types.go
+++ b/internal/adapters/keycloak/types.go
@@ -23,10 +23,13 @@ type Client interface {
 // Options configures Keycloak mapping without making Keycloak the source of
 // truth for flex-auth resources or policies.
 type Options struct {
-	Realm         string
-	Audience      string
-	PolicyPackage string
-	PolicyVersion string
+	Realm                  string
+	Audience               string
+	PolicyPackage          string
+	PolicyVersion          string
+	PolicyPackageDigest    string
+	RegistrySnapshotDigest string
+	AllowTTL               string
 }
 
 // AuthorizationRequest is the UMA permission request flex-auth sends to
diff --git a/internal/adapters/relationship/adapter.go b/internal/adapters/relationship/adapter.go
index e6b3ab5..67061aa 100644
--- a/internal/adapters/relationship/adapter.go
+++ b/internal/adapters/relationship/adapter.go
@@ -14,10 +14,13 @@ import (
 
 // Adapter wraps tuple-oriented PDP results into flex-auth decision envelopes.
 type Adapter struct {
-	backend       Backend
-	backendName   string
-	policyPackage string
-	policyVersion string
+	backend                Backend
+	backendName            string
+	policyPackage          string
+	policyVersion          string
+	policyPackageDigest    string
+	registrySnapshotDigest string
+	allowTTL               string
 }
 
 // New creates a relationship PDP adapter.
@@ -30,10 +33,13 @@ func New(backend Backend, options Options) (*Adapter, error) {
 		backendName = "relationship"
 	}
 	return &Adapter{
-		backend:       backend,
-		backendName:   backendName,
-		policyPackage: options.PolicyPackage,
-		policyVersion: options.PolicyVersion,
+		backend:                backend,
+		backendName:            backendName,
+		policyPackage:          options.PolicyPackage,
+		policyVersion:          options.PolicyVersion,
+		policyPackageDigest:    options.PolicyPackageDigest,
+		registrySnapshotDigest: options.RegistrySnapshotDigest,
+		allowTTL:               options.AllowTTL,
 	}, nil
 }
 
@@ -230,7 +236,8 @@ func (a *Adapter) envelope(request api.CheckRequest, tupleRequest TupleCheckRequ
 		},
 		Caring: caringDecisionMetadata(request, descriptorForResult(request, result), result.ConformanceFindings),
 	}
-	envelope.ID = decisionID(a.backendName, a.policyPackage, policyVersion, request, effect, reason, result.ConsistencyToken)
+	envelope = a.finish(request, envelope)
+	envelope.ID = decisionID(a.backendName, a.policyPackage, policyVersion, request, envelope.Effect, envelope.Reason, result.ConsistencyToken)
 	return envelope
 }
 
@@ -255,10 +262,22 @@ func (a *Adapter) failureEnvelope(request api.CheckRequest, tupleRequest TupleCh
 		},
 		Caring: caringDecisionMetadata(request, request.CaringContext, []api.CaringConformanceFinding{failureFinding(kind)}),
 	}
+	envelope = a.finish(request, envelope)
 	envelope.ID = decisionID(a.backendName, a.policyPackage, policyVersion, request, envelope.Effect, envelope.Reason, "")
 	return envelope
 }
 
+func (a *Adapter) finish(request api.CheckRequest, envelope api.DecisionEnvelope) api.DecisionEnvelope {
+	if envelope.Provenance.RegistrySnapshotDigest == "" {
+		envelope.Provenance.RegistrySnapshotDigest = a.registrySnapshotDigest
+	}
+	if envelope.Provenance.PolicyPackageDigest == "" {
+		envelope.Provenance.PolicyPackageDigest = a.policyPackageDigest
+	}
+	api.CompleteDecision(&envelope, request, api.DecisionCompletion{AllowTTL: a.allowTTL})
+	return envelope
+}
+
 func descriptorForResult(request api.CheckRequest, result TupleCheckResult) *api.CaringAccessDescriptor {
 	if request.CaringContext != nil {
 		return request.CaringContext
diff --git a/internal/adapters/relationship/types.go b/internal/adapters/relationship/types.go
index dc0b184..94bb075 100644
--- a/internal/adapters/relationship/types.go
+++ b/internal/adapters/relationship/types.go
@@ -27,9 +27,12 @@ type Backend interface {
 // Options configures the relationship adapter without binding callers to a
 // specific backend protocol.
 type Options struct {
-	BackendName   string
-	PolicyPackage string
-	PolicyVersion string
+	BackendName            string
+	PolicyPackage          string
+	PolicyVersion          string
+	PolicyPackageDigest    string
+	RegistrySnapshotDigest string
+	AllowTTL               string
 }
 
 // Tuple is the canonical relation fact sent to tuple-oriented PDPs.
diff --git a/internal/adapters/rule/adapter.go b/internal/adapters/rule/adapter.go
index 8649ed9..64216ee 100644
--- a/internal/adapters/rule/adapter.go
+++ b/internal/adapters/rule/adapter.go
@@ -14,12 +14,15 @@ import (
 
 // Adapter wraps rule-PDP responses into flex-auth decision envelopes.
 type Adapter struct {
-	backend       Backend
-	backendName   string
-	policyPackage string
-	policyVersion string
-	language      Language
-	caring        api.CaringPolicyMetadata
+	backend                Backend
+	backendName            string
+	policyPackage          string
+	policyVersion          string
+	policyPackageDigest    string
+	registrySnapshotDigest string
+	allowTTL               string
+	language               Language
+	caring                 api.CaringPolicyMetadata
 }
 
 // New creates a delegated rule-PDP adapter.
@@ -36,12 +39,15 @@ func New(backend Backend, options Options) (*Adapter, error) {
 		language = LanguageRego
 	}
 	return &Adapter{
-		backend:       backend,
-		backendName:   backendName,
-		policyPackage: options.PolicyPackage,
-		policyVersion: options.PolicyVersion,
-		language:      language,
-		caring:        options.Caring,
+		backend:                backend,
+		backendName:            backendName,
+		policyPackage:          options.PolicyPackage,
+		policyVersion:          options.PolicyVersion,
+		policyPackageDigest:    options.PolicyPackageDigest,
+		registrySnapshotDigest: options.RegistrySnapshotDigest,
+		allowTTL:               options.AllowTTL,
+		language:               language,
+		caring:                 options.Caring,
 	}, nil
 }
 
@@ -234,7 +240,8 @@ func (a *Adapter) envelope(request api.CheckRequest, evaluation EvaluationReques
 		},
 		Caring: caringDecisionMetadata(request, firstDescriptor(request.CaringContext, result.CaringDescriptor), a.caring, result.ConformanceFindings),
 	}
-	envelope.ID = decisionID(a.backendName, policyPackage, policyVersion, request, effect, reason)
+	envelope = a.finish(request, envelope)
+	envelope.ID = decisionID(a.backendName, policyPackage, policyVersion, request, envelope.Effect, envelope.Reason)
 	return envelope
 }
 
@@ -259,10 +266,22 @@ func (a *Adapter) failureEnvelope(request api.CheckRequest, evaluation Evaluatio
 		},
 		Caring: caringDecisionMetadata(request, request.CaringContext, a.caring, []api.CaringConformanceFinding{failureFinding(kind)}),
 	}
+	envelope = a.finish(request, envelope)
 	envelope.ID = decisionID(a.backendName, a.policyPackage, policyVersion, request, envelope.Effect, envelope.Reason)
 	return envelope
 }
 
+func (a *Adapter) finish(request api.CheckRequest, envelope api.DecisionEnvelope) api.DecisionEnvelope {
+	if envelope.Provenance.RegistrySnapshotDigest == "" {
+		envelope.Provenance.RegistrySnapshotDigest = a.registrySnapshotDigest
+	}
+	if envelope.Provenance.PolicyPackageDigest == "" {
+		envelope.Provenance.PolicyPackageDigest = a.policyPackageDigest
+	}
+	api.CompleteDecision(&envelope, request, api.DecisionCompletion{AllowTTL: a.allowTTL})
+	return envelope
+}
+
 func caringDecisionMetadata(
 	request api.CheckRequest,
 	descriptor *api.CaringAccessDescriptor,
diff --git a/internal/adapters/rule/types.go b/internal/adapters/rule/types.go
index 922073a..3cf6630 100644
--- a/internal/adapters/rule/types.go
+++ b/internal/adapters/rule/types.go
@@ -33,11 +33,14 @@ type Backend interface {
 
 // Options configures the rule adapter.
 type Options struct {
-	BackendName   string
-	PolicyPackage string
-	PolicyVersion string
-	Language      Language
-	Caring        api.CaringPolicyMetadata
+	BackendName            string
+	PolicyPackage          string
+	PolicyVersion          string
+	PolicyPackageDigest    string
+	RegistrySnapshotDigest string
+	AllowTTL               string
+	Language               Language
+	Caring                 api.CaringPolicyMetadata
 }
 
 // EvaluationRequest is the canonical rule-PDP request.
diff --git a/internal/adapters/topaz/adapter.go b/internal/adapters/topaz/adapter.go
index 2f1708a..d336dae 100644
--- a/internal/adapters/topaz/adapter.go
+++ b/internal/adapters/topaz/adapter.go
@@ -16,9 +16,12 @@ import (
 // Adapter delegates checks, directory writes, and policy bundle publication to
 // Topaz while preserving flex-auth request and decision contracts.
 type Adapter struct {
-	client        Client
-	policyPackage string
-	policyVersion string
+	client                 Client
+	policyPackage          string
+	policyVersion          string
+	policyPackageDigest    string
+	registrySnapshotDigest string
+	allowTTL               string
 }
 
 // New creates a Topaz adapter.
@@ -27,9 +30,12 @@ func New(client Client, options Options) (*Adapter, error) {
 		return nil, fmt.Errorf("topaz client is required")
 	}
 	return &Adapter{
-		client:        client,
-		policyPackage: options.PolicyPackage,
-		policyVersion: options.PolicyVersion,
+		client:                 client,
+		policyPackage:          options.PolicyPackage,
+		policyVersion:          options.PolicyVersion,
+		policyPackageDigest:    options.PolicyPackageDigest,
+		registrySnapshotDigest: options.RegistrySnapshotDigest,
+		allowTTL:               options.AllowTTL,
 	}, nil
 }
 
@@ -202,6 +208,7 @@ func (a *Adapter) envelope(request api.CheckRequest, topazRequest DirectoryCheck
 		},
 		Caring: caringDecisionMetadata(request, firstDescriptor(request.CaringContext, result.CaringDescriptor), result.ConformanceFindings, result.ExposureEvent),
 	}
+	envelope = a.finish(request, envelope)
 	envelope.ID = decisionID(policyPackage, policyVersion, request, envelope.Effect, envelope.Reason, result.DirectoryETag)
 	if envelope.Caring != nil && envelope.Caring.ExposureEvent != nil && envelope.Caring.ExposureEvent.ID == "" {
 		envelope.Caring.ExposureEvent.ID = envelope.ID + ":exposure"
@@ -237,10 +244,22 @@ func (a *Adapter) failureEnvelope(request api.CheckRequest, topazRequest Directo
 		},
 		Caring: caringDecisionMetadata(request, request.CaringContext, findings, nil),
 	}
+	envelope = a.finish(request, envelope)
 	envelope.ID = decisionID(a.policyPackage, policyVersion, request, envelope.Effect, envelope.Reason, "")
 	return envelope
 }
 
+func (a *Adapter) finish(request api.CheckRequest, envelope api.DecisionEnvelope) api.DecisionEnvelope {
+	if envelope.Provenance.RegistrySnapshotDigest == "" {
+		envelope.Provenance.RegistrySnapshotDigest = a.registrySnapshotDigest
+	}
+	if envelope.Provenance.PolicyPackageDigest == "" {
+		envelope.Provenance.PolicyPackageDigest = a.policyPackageDigest
+	}
+	api.CompleteDecision(&envelope, request, api.DecisionCompletion{AllowTTL: a.allowTTL})
+	return envelope
+}
+
 func addTopazDiagnostics(diagnostics map[string]any, request DirectoryCheckRequest, failure string) {
 	diagnostics["adapter"] = "topaz"
 	diagnostics["mode"] = DelegatedMode
diff --git a/internal/adapters/topaz/adapter_test.go b/internal/adapters/topaz/adapter_test.go
index 5b7d154..29a6643 100644
--- a/internal/adapters/topaz/adapter_test.go
+++ b/internal/adapters/topaz/adapter_test.go
@@ -86,6 +86,12 @@ func TestAdapterCheckWrapsTopazAllowInFlexAuthEnvelope(t *testing.T) {
 	if got.Provenance.DirectoryETag != "etag:rel-42" {
 		t.Fatalf("DirectoryETag = %q", got.Provenance.DirectoryETag)
 	}
+	if got.Provenance.RegistrySnapshotDigest != "sha256:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" {
+		t.Fatalf("RegistrySnapshotDigest = %q", got.Provenance.RegistrySnapshotDigest)
+	}
+	if got.Lifetime == nil || got.Lifetime.Kind != api.DecisionLifetimeTTL {
+		t.Fatalf("lifetime = %+v; want default ttl", got.Lifetime)
+	}
 	if got.Diagnostics["topaz_object_type"] != "document" || got.Diagnostics["topaz_subject_type"] != "user" {
 		t.Fatalf("diagnostics = %+v; want Topaz check shape", got.Diagnostics)
 	}
@@ -201,8 +207,9 @@ func newAdapter(t *testing.T, client *fakeClient) *topaz.Adapter {
 	t.Helper()
 
 	adapter, err := topaz.New(client, topaz.Options{
-		PolicyPackage: "markitect.documents.internal-read",
-		PolicyVersion: "v1",
+		PolicyPackage:          "markitect.documents.internal-read",
+		PolicyVersion:          "v1",
+		RegistrySnapshotDigest: "sha256:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
 	})
 	if err != nil {
 		t.Fatalf("New: %v", err)
diff --git a/internal/adapters/topaz/types.go b/internal/adapters/topaz/types.go
index aa8b87b..f490573 100644
--- a/internal/adapters/topaz/types.go
+++ b/internal/adapters/topaz/types.go
@@ -41,8 +41,11 @@ type BundleSink interface {
 // Options configures the adapter without leaking Topaz-specific types into the
 // public flex-auth API.
 type Options struct {
-	PolicyPackage string
-	PolicyVersion string
+	PolicyPackage          string
+	PolicyVersion          string
+	PolicyPackageDigest    string
+	RegistrySnapshotDigest string
+	AllowTTL               string
 }
 
 // DirectoryObject is the Topaz directory object shape used by the REST
diff --git a/internal/decision/engine.go b/internal/decision/engine.go
index ba7e6cf..33d8dc6 100644
--- a/internal/decision/engine.go
+++ b/internal/decision/engine.go
@@ -10,6 +10,7 @@ import (
 	"slices"
 	"strings"
 	"sync"
+	"time"
 
 	"github.com/netkingdom/flex-auth/internal/policy"
 	"github.com/netkingdom/flex-auth/internal/registry"
@@ -24,6 +25,7 @@ type Engine struct {
 	mu      sync.RWMutex
 	history map[string]api.DecisionEnvelope
 	log     DecisionRecorder
+	clock   func() time.Time
 }
 
 // DecisionRecorder persists decision envelopes.
@@ -82,6 +84,23 @@ func (e *Engine) SetDecisionLog(log DecisionRecorder) {
 	e.log = log
 }
 
+// SetClock overrides the engine clock. Tests use this to pin allow lifetimes.
+func (e *Engine) SetClock(clock func() time.Time) {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+	e.clock = clock
+}
+
+func (e *Engine) now() time.Time {
+	e.mu.RLock()
+	clock := e.clock
+	e.mu.RUnlock()
+	if clock != nil {
+		return clock().UTC()
+	}
+	return time.Now().UTC()
+}
+
 // Check evaluates one subject/action/resource request.
 func (e *Engine) Check(ctx context.Context, request api.CheckRequest) (api.DecisionEnvelope, error) {
 	normalized, facts := e.normalizeRequest(request)
@@ -307,13 +326,19 @@ func (e *Engine) envelope(request api.CheckRequest, expectation api.DecisionExpe
 			"matched_relationship": facts.matchedRelationship,
 		},
 		Provenance: api.DecisionProvenance{
-			Evaluator:     "flex-auth/local",
-			Mode:          "standalone",
-			PolicyPackage: e.policy.Metadata.ID,
-			PolicyVersion: e.policy.Metadata.Version,
+			Evaluator:              "flex-auth/local",
+			Mode:                   "standalone",
+			PolicyPackage:          e.policy.Metadata.ID,
+			PolicyVersion:          e.policy.Metadata.Version,
+			PolicyPackageDigest:    e.policy.Digest(),
+			RegistrySnapshotDigest: e.store.Digest(),
 		},
 		Caring: e.caringDecisionMetadata(facts.descriptor, expectation.ConformanceFindings),
 	}
+	api.CompleteDecision(&envelope, request, api.DecisionCompletion{
+		AllowTTL: e.policy.Metadata.AllowTTL,
+		Now:      e.now(),
+	})
 	envelope.ID = decisionID(e.policy.Metadata, request, envelope)
 	return envelope
 }
diff --git a/internal/decision/engine_test.go b/internal/decision/engine_test.go
index 804d446..fd1c8cf 100644
--- a/internal/decision/engine_test.go
+++ b/internal/decision/engine_test.go
@@ -6,6 +6,7 @@ import (
 	"path/filepath"
 	"strings"
 	"testing"
+	"time"
 
 	"gopkg.in/yaml.v3"
 
@@ -198,6 +199,112 @@ func TestExplainUsesRecordedDecision(t *testing.T) {
 	}
 }
 
+func TestCheckRecordsRegistrySnapshotDigest(t *testing.T) {
+	store := newTestStore(t)
+	engine := newTestEngineWithStore(t, store)
+	want := store.Digest()
+
+	first, err := engine.Check(context.Background(), api.CheckRequest{
+		Subject:  api.SubjectRef{ID: "user:alice"},
+		Action:   "read",
+		Resource: api.ResourceRef{ID: "document:internal-note", System: "markitect-tool"},
+	})
+	if err != nil {
+		t.Fatalf("Check: %v", err)
+	}
+	if first.Provenance.RegistrySnapshotDigest != want {
+		t.Fatalf("digest = %q; want %q", first.Provenance.RegistrySnapshotDigest, want)
+	}
+	if first.Provenance.PolicyPackageDigest == "" || !strings.HasPrefix(first.Provenance.PolicyPackageDigest, "sha256:") {
+		t.Fatalf("policy package digest = %q", first.Provenance.PolicyPackageDigest)
+	}
+
+	second, err := engine.Check(context.Background(), api.CheckRequest{
+		Subject:  api.SubjectRef{ID: "user:alice"},
+		Action:   "read",
+		Resource: api.ResourceRef{ID: "document:internal-note", System: "markitect-tool"},
+	})
+	if err != nil {
+		t.Fatalf("Check again: %v", err)
+	}
+	if second.Provenance.RegistrySnapshotDigest != want {
+		t.Fatal("two decisions over the same snapshot disagree on digest")
+	}
+
+	if err := store.ImportResourceManifest(api.ResourceManifest{
+		ID:     "markitect-extra",
+		System: "markitect-tool",
+		Resources: []api.Resource{
+			{ID: "document:other-note", Type: "document"},
+		},
+	}); err != nil {
+		t.Fatalf("ImportResourceManifest: %v", err)
+	}
+	changedEngine := newTestEngineWithStore(t, store)
+	changed, err := changedEngine.Check(context.Background(), api.CheckRequest{
+		Subject:  api.SubjectRef{ID: "user:alice"},
+		Action:   "read",
+		Resource: api.ResourceRef{ID: "document:internal-note", System: "markitect-tool"},
+	})
+	if err != nil {
+		t.Fatalf("Check after snapshot change: %v", err)
+	}
+	if changed.Provenance.RegistrySnapshotDigest == want {
+		t.Fatal("changed snapshot kept the same digest")
+	}
+}
+
+func TestCheckAllowLifetimes(t *testing.T) {
+	fixed := time.Date(2026, 8, 29, 12, 0, 0, 0, time.UTC)
+	request := api.CheckRequest{
+		Subject:  api.SubjectRef{ID: "user:alice"},
+		Action:   "read",
+		Resource: api.ResourceRef{ID: "document:internal-note", System: "markitect-tool"},
+	}
+
+	defaulted := newTestEngine(t)
+	defaulted.SetClock(func() time.Time { return fixed })
+	got, err := defaulted.Check(context.Background(), request)
+	if err != nil {
+		t.Fatalf("default Check: %v", err)
+	}
+	if got.Effect != api.DecisionEffectAllow || got.Lifetime == nil || got.Lifetime.TTL != "15m" {
+		t.Fatalf("defaulted allow = %+v", got)
+	}
+	if got.Lifetime.ExpiresAt != "2026-08-29T12:15:00Z" {
+		t.Fatalf("default expires_at = %q", got.Lifetime.ExpiresAt)
+	}
+	if got.ContractVersion != api.DecisionRecordContractV1 {
+		t.Fatalf("contract_version = %q", got.ContractVersion)
+	}
+
+	declared := newTestEngineWithTTL(t, "5m")
+	declared.SetClock(func() time.Time { return fixed })
+	got, err = declared.Check(context.Background(), request)
+	if err != nil {
+		t.Fatalf("declared Check: %v", err)
+	}
+	if got.Effect != api.DecisionEffectAllow || got.Lifetime == nil || got.Lifetime.TTL != "5m" {
+		t.Fatalf("declared allow = %+v", got)
+	}
+	if got.Lifetime.ExpiresAt != "2026-08-29T12:05:00Z" {
+		t.Fatalf("declared expires_at = %q", got.Lifetime.ExpiresAt)
+	}
+
+	unstated := newTestEngineWithTTL(t, "none")
+	unstated.SetClock(func() time.Time { return fixed })
+	got, err = unstated.Check(context.Background(), request)
+	if err != nil {
+		t.Fatalf("unstated Check: %v", err)
+	}
+	if got.Effect != api.DecisionEffectDeny || got.Reason != api.ReasonAllowLifetimeUnstated {
+		t.Fatalf("unstated allow = %s/%s; want deny/%s", got.Effect, got.Reason, api.ReasonAllowLifetimeUnstated)
+	}
+	if got.Lifetime != nil {
+		t.Fatalf("unstated deny still has lifetime %+v", got.Lifetime)
+	}
+}
+
 func TestCheckWritesDecisionLog(t *testing.T) {
 	engine := newTestEngine(t)
 	log := audit.NewJSONLDecisionLog(filepath.Join(t.TempDir(), "decisions.jsonl"))
@@ -240,11 +347,22 @@ func newTestEngine(t *testing.T) *decision.Engine {
 
 func newTestEngineWithStore(t *testing.T, store *registry.Store) *decision.Engine {
 	t.Helper()
+	return newTestEngineWithStoreAndTTL(t, store, "")
+}
+
+func newTestEngineWithTTL(t *testing.T, allowTTL string) *decision.Engine {
+	t.Helper()
+	return newTestEngineWithStoreAndTTL(t, newTestStore(t), allowTTL)
+}
+
+func newTestEngineWithStoreAndTTL(t *testing.T, store *registry.Store, allowTTL string) *decision.Engine {
+	t.Helper()
 
 	policyPackage, err := policy.LoadAndValidateFile(context.Background(), filepath.Join("..", "..", "examples", "caring", "policy_package.md"))
 	if err != nil {
 		t.Fatalf("LoadAndValidateFile policy: %v", err)
 	}
+	policyPackage.Metadata.AllowTTL = allowTTL
 	engine, err := decision.NewEngine(store, policyPackage)
 	if err != nil {
 		t.Fatalf("NewEngine: %v", err)
diff --git a/internal/layer/conformance.go b/internal/layer/conformance.go
new file mode 100644
index 0000000..f65cabd
--- /dev/null
+++ b/internal/layer/conformance.go
@@ -0,0 +1,147 @@
+// Package layer asserts the NetKingdom security-layer-model §11 declaration.
+package layer
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+
+	"gopkg.in/yaml.v3"
+)
+
+// Layer vocabulary from security-layer-model_v0.7 §3.
+var validLayers = map[string]bool{
+	"Staff":   true,
+	"Engine":  true,
+	"Tooling": true,
+}
+
+// Engine roles from §3.3. An Engine declaration must state one.
+var validEngineRoles = map[string]bool{
+	"PDP": true,
+	"PIP": true,
+}
+
+// Tooling clients are invocations, not mentions. These match import paths and
+// argv construction that would actually contact OpenBao/Vault.
+var toolingPatterns = []*regexp.Regexp{
+	regexp.MustCompile(`github\.com/hashicorp/vault`),
+	regexp.MustCompile(`github\.com/openbao/`),
+	regexp.MustCompile(`exec\.Command\([^)]*["'](?:bao|vault)["']`),
+}
+
+// Declaration is the machine-readable §11 form carried in INTENT.md frontmatter.
+type Declaration struct {
+	Layer           string `yaml:"layer"`
+	Role            string `yaml:"role"`
+	Framework       string `yaml:"framework"`
+	StandardVersion string `yaml:"standard_version"`
+	DeclaredBy      string `yaml:"declared_by"`
+	DeclaredAt      string `yaml:"declared_at"`
+	PepStance       any    `yaml:"pep_stance"`
+	ToolingContacts []any  `yaml:"tooling_contacts"`
+}
+
+// Check parses INTENT.md, asserts the Engine/PDP declaration, and scans
+// production Go sources for undeclared Tooling clients.
+func Check(root string) error {
+	decl, err := LoadDeclaration(filepath.Join(root, "INTENT.md"))
+	if err != nil {
+		return err
+	}
+	if err := ValidateDeclaration(decl); err != nil {
+		return err
+	}
+	hits, err := ScanToolingClients(root)
+	if err != nil {
+		return err
+	}
+	if len(hits) > 0 {
+		return fmt.Errorf("undeclared Tooling client(s) under §11: %s", strings.Join(hits, "; "))
+	}
+	return nil
+}
+
+// LoadDeclaration reads YAML frontmatter from INTENT.md.
+func LoadDeclaration(path string) (Declaration, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return Declaration{}, fmt.Errorf("read layer declaration: %w", err)
+	}
+	frontmatter, err := splitFrontmatter(string(data))
+	if err != nil {
+		return Declaration{}, err
+	}
+	var decl Declaration
+	if err := yaml.Unmarshal([]byte(frontmatter), &decl); err != nil {
+		return Declaration{}, fmt.Errorf("parse layer declaration: %w", err)
+	}
+	return decl, nil
+}
+
+// ValidateDeclaration asserts §3 vocabulary and Engine-role presence.
+func ValidateDeclaration(decl Declaration) error {
+	if !validLayers[decl.Layer] {
+		return fmt.Errorf("layer %q is not in the §3 vocabulary (Staff, Engine, Tooling)", decl.Layer)
+	}
+	if decl.Layer == "Engine" && !validEngineRoles[decl.Role] {
+		return fmt.Errorf("Engine declaration must state role PDP or PIP; got %q", decl.Role)
+	}
+	if decl.Layer != "Engine" && strings.TrimSpace(decl.Role) != "" {
+		return fmt.Errorf("layer %q must not state an Engine role", decl.Layer)
+	}
+	if len(decl.ToolingContacts) > 0 {
+		return fmt.Errorf("Engine/PDP holds no Tooling client; tooling_contacts must be empty")
+	}
+	if decl.PepStance != nil {
+		return fmt.Errorf("flex-auth is not PEP-shaped; pep_stance must be null")
+	}
+	return nil
+}
+
+// ScanToolingClients returns production Go files that invoke OpenBao/Vault.
+func ScanToolingClients(root string) ([]string, error) {
+	var hits []string
+	for _, dir := range []string{"cmd", "internal", "pkg"} {
+		err := filepath.WalkDir(filepath.Join(root, dir), func(path string, d os.DirEntry, err error) error {
+			if err != nil {
+				return err
+			}
+			if d.IsDir() || !strings.HasSuffix(path, ".go") || strings.HasSuffix(path, "_test.go") {
+				return nil
+			}
+			body, err := os.ReadFile(path)
+			if err != nil {
+				return err
+			}
+			for _, pattern := range toolingPatterns {
+				if pattern.Find(body) != nil {
+					rel, _ := filepath.Rel(root, path)
+					hits = append(hits, rel)
+					break
+				}
+			}
+			return nil
+		})
+		if err != nil && !os.IsNotExist(err) {
+			return nil, err
+		}
+	}
+	return hits, nil
+}
+
+func splitFrontmatter(document string) (string, error) {
+	document = strings.TrimPrefix(document, "\ufeff")
+	lines := strings.SplitAfter(document, "\n")
+	if len(lines) == 0 || strings.TrimSpace(lines[0]) != "---" {
+		return "", fmt.Errorf("INTENT.md must start with YAML frontmatter")
+	}
+	for i := 1; i < len(lines); i++ {
+		if strings.TrimSpace(lines[i]) == "---" {
+			return strings.Join(lines[1:i], ""), nil
+		}
+	}
+	return "", fmt.Errorf("INTENT.md frontmatter is not closed")
+}
diff --git a/internal/layer/conformance_test.go b/internal/layer/conformance_test.go
new file mode 100644
index 0000000..5f4dba0
--- /dev/null
+++ b/internal/layer/conformance_test.go
@@ -0,0 +1,56 @@
+package layer_test
+
+import (
+	"path/filepath"
+	"runtime"
+	"testing"
+
+	"github.com/netkingdom/flex-auth/internal/layer"
+)
+
+func TestLayerDeclarationConforms(t *testing.T) {
+	root := repoRoot(t)
+	if err := layer.Check(root); err != nil {
+		t.Fatalf("layer conformance: %v", err)
+	}
+
+	decl, err := layer.LoadDeclaration(filepath.Join(root, "INTENT.md"))
+	if err != nil {
+		t.Fatalf("LoadDeclaration: %v", err)
+	}
+	if decl.Layer != "Engine" {
+		t.Fatalf("layer = %q; want Engine", decl.Layer)
+	}
+	if decl.Role != "PDP" {
+		t.Fatalf("role = %q; want PDP", decl.Role)
+	}
+	if decl.Framework != "netkingdom-security-layer-model" {
+		t.Fatalf("framework = %q", decl.Framework)
+	}
+	if decl.StandardVersion != "0.7" {
+		t.Fatalf("standard_version = %q; want 0.7", decl.StandardVersion)
+	}
+}
+
+func TestEngineWithoutRoleIsRejected(t *testing.T) {
+	err := layer.ValidateDeclaration(layer.Declaration{Layer: "Engine"})
+	if err == nil {
+		t.Fatal("Engine without role was accepted")
+	}
+}
+
+func TestUnknownLayerIsRejected(t *testing.T) {
+	err := layer.ValidateDeclaration(layer.Declaration{Layer: "ControlPlane", Role: "PDP"})
+	if err == nil {
+		t.Fatal("unknown layer was accepted")
+	}
+}
+
+func repoRoot(t *testing.T) string {
+	t.Helper()
+	_, file, _, ok := runtime.Caller(0)
+	if !ok {
+		t.Fatal("runtime.Caller failed")
+	}
+	return filepath.Clean(filepath.Join(filepath.Dir(file), "..", ".."))
+}
diff --git a/internal/policy/package.go b/internal/policy/package.go
index bf28492..644d5aa 100644
--- a/internal/policy/package.go
+++ b/internal/policy/package.go
@@ -8,6 +8,7 @@ import (
 	"path/filepath"
 	"sort"
 	"strings"
+	"time"
 
 	"github.com/open-policy-agent/opa/ast"
 	"github.com/open-policy-agent/opa/rego"
@@ -148,6 +149,17 @@ func (p *Package) Evaluate(ctx context.Context, request api.CheckRequest) (api.D
 	return p.evaluateDecision(ctx, request)
 }
 
+// Digest is the SHA-256 of canonical metadata plus the compiled Rego module.
+func (p *Package) Digest() string {
+	return api.CanonicalDigest(struct {
+		Metadata   api.PolicyPackageMetadata `json:"metadata"`
+		RegoModule string                    `json:"rego_module"`
+	}{
+		Metadata:   p.Metadata,
+		RegoModule: p.RegoModule,
+	})
+}
+
 // Validate runs metadata, CARING, OPA parse/test, and fixture validation.
 func (p *Package) Validate(ctx context.Context) ValidationResult {
 	result := ValidationResult{}
@@ -235,6 +247,24 @@ func (p *Package) metadataDiagnostics() []Diagnostic {
 	if p.Metadata.Package == "" {
 		diagnostics = append(diagnostics, requiredDiagnostic("POLICY-METADATA-PACKAGE", "package", "OPA package path is required"))
 	}
+	if strings.TrimSpace(p.Metadata.AllowTTL) != "" && !strings.EqualFold(strings.TrimSpace(p.Metadata.AllowTTL), "none") {
+		ttl, err := time.ParseDuration(strings.TrimSpace(p.Metadata.AllowTTL))
+		if err != nil {
+			diagnostics = append(diagnostics, Diagnostic{
+				Code:     "POLICY-ALLOW-TTL-INVALID",
+				Severity: "error",
+				Message:  fmt.Sprintf("allow_ttl %q is not a Go duration", p.Metadata.AllowTTL),
+				Fields:   []string{"allow_ttl"},
+			})
+		} else if ttl < 0 {
+			diagnostics = append(diagnostics, Diagnostic{
+				Code:     "POLICY-ALLOW-TTL-INVALID",
+				Severity: "error",
+				Message:  "allow_ttl must be none, 0s, or a positive duration",
+				Fields:   []string{"allow_ttl"},
+			})
+		}
+	}
 	return diagnostics
 }
 
diff --git a/internal/registry/store.go b/internal/registry/store.go
index 979ff50..ad873aa 100644
--- a/internal/registry/store.go
+++ b/internal/registry/store.go
@@ -137,6 +137,12 @@ func (s *Store) Snapshot() Snapshot {
 	}
 }
 
+// Digest is the SHA-256 of the canonical JSON snapshot. Two stores with the
+// same records agree; a changed record changes the digest.
+func (s *Store) Digest() string {
+	return api.CanonicalDigest(s.Snapshot())
+}
+
 // PutProtectedSystem stores or replaces a protected system manifest.
 func (s *Store) PutProtectedSystem(system api.ProtectedSystemManifest) error {
 	if system.ID == "" {
diff --git a/internal/registry/store_test.go b/internal/registry/store_test.go
index 2de1cbc..60e6918 100644
--- a/internal/registry/store_test.go
+++ b/internal/registry/store_test.go
@@ -3,6 +3,7 @@ package registry_test
 import (
 	"encoding/json"
 	"path/filepath"
+	"strings"
 	"testing"
 
 	"github.com/netkingdom/flex-auth/internal/registry"
@@ -70,6 +71,33 @@ func TestStoreLoadsAndSavesDeterministicSnapshot(t *testing.T) {
 	}
 }
 
+func TestStoreDigestChangesWhenSnapshotChanges(t *testing.T) {
+	store, err := registry.LoadFile(filepath.Join("..", "..", "examples", "caring", "registry_snapshot.json"))
+	if err != nil {
+		t.Fatalf("LoadFile: %v", err)
+	}
+	first := store.Digest()
+	if !strings.HasPrefix(first, "sha256:") || len(first) != len("sha256:")+64 {
+		t.Fatalf("Digest = %q", first)
+	}
+	if store.Digest() != first {
+		t.Fatal("digest is not stable for an unchanged snapshot")
+	}
+
+	if err := store.ImportResourceManifest(api.ResourceManifest{
+		ID:     "markitect-extra",
+		System: "markitect-tool",
+		Resources: []api.Resource{
+			{ID: "document:other-note", Type: "document"},
+		},
+	}); err != nil {
+		t.Fatalf("ImportResourceManifest: %v", err)
+	}
+	if store.Digest() == first {
+		t.Fatal("digest did not change after snapshot mutation")
+	}
+}
+
 func TestStoreRejectsInvalidRecords(t *testing.T) {
 	store := registry.NewStore()
 	if err := store.PutSubject(api.Subject{}); err == nil {
diff --git a/pkg/api/canonical.go b/pkg/api/canonical.go
index 9163e95..f450c39 100644
--- a/pkg/api/canonical.go
+++ b/pkg/api/canonical.go
@@ -4,6 +4,9 @@ import (
 	"crypto/sha256"
 	"encoding/hex"
 	"encoding/json"
+	"fmt"
+	"strings"
+	"time"
 )
 
 // ProtectedSystemManifest describes a system that delegates authorization to
@@ -118,6 +121,10 @@ type PolicyPackageMetadata struct {
 	Caring     CaringPolicyMetadata `json:"caring"                yaml:"caring"`
 	Activation map[string]any       `json:"activation,omitempty"  yaml:"activation,omitempty"`
 	Metadata   map[string]any       `json:"metadata,omitempty"    yaml:"metadata,omitempty"`
+	// AllowTTL is a Go duration (for example "15m") that bounds every allow
+	// this package produces. Omit to use DefaultAllowTTL. "none" or "0s"
+	// means no stated end; the engine denies those allows (§9.7.1).
+	AllowTTL string `json:"allow_ttl,omitempty" yaml:"allow_ttl,omitempty"`
 }
 
 // CaringPolicyMetadata declares the CARING envelope a policy governs.
@@ -202,10 +209,14 @@ const (
 	DecisionEffectNotApplicable DecisionEffect = "not_applicable"
 )
 
+// DecisionRecordContractV1 is the published decision-record contract identifier.
+const DecisionRecordContractV1 = "flex-auth.decision-record.v1"
+
 // DecisionEnvelope is the stable response produced by standalone and delegated
-// evaluators.
+// evaluators. It is flex-auth's published decision-record contract (§17).
 type DecisionEnvelope struct {
 	ID                   string                  `json:"id"                              yaml:"id"`
+	ContractVersion      string                  `json:"contract_version,omitempty"      yaml:"contract_version,omitempty"`
 	RequestID            string                  `json:"request_id,omitempty"            yaml:"request_id,omitempty"`
 	Effect               DecisionEffect          `json:"effect"                          yaml:"effect"`
 	Reason               string                  `json:"reason,omitempty"                yaml:"reason,omitempty"`
@@ -214,12 +225,35 @@ type DecisionEnvelope struct {
 	Resource             ResourceRef             `json:"resource"                        yaml:"resource"`
 	Subject              SubjectRef              `json:"subject"                         yaml:"subject"`
 	Binding              *DecisionBinding        `json:"binding,omitempty"               yaml:"binding,omitempty"`
+	Lifetime             *DecisionLifetime       `json:"lifetime,omitempty"              yaml:"lifetime,omitempty"`
 	Obligations          []Obligation            `json:"obligations,omitempty"           yaml:"obligations,omitempty"`
 	Diagnostics          map[string]any          `json:"diagnostics,omitempty"           yaml:"diagnostics,omitempty"`
 	Provenance           DecisionProvenance      `json:"provenance"                      yaml:"provenance"`
 	Caring               *CaringDecisionMetadata `json:"caring,omitempty"                yaml:"caring,omitempty"`
 }
 
+// DecisionLifetimeKind identifies how an allow ends.
+type DecisionLifetimeKind string
+
+const (
+	DecisionLifetimeTTL DecisionLifetimeKind = "ttl"
+)
+
+// DefaultAllowTTL is the engine default when a policy package omits allow_ttl.
+const DefaultAllowTTL = 15 * time.Minute
+
+// ReasonAllowLifetimeUnstated is the deny reason for an allow with no stated end.
+const ReasonAllowLifetimeUnstated = "allow_lifetime_unstated"
+
+// DecisionLifetime bounds an allow (§9.7.1). flex-auth has no session concept,
+// so the first honest shape is a policy-package-declared TTL.
+type DecisionLifetime struct {
+	Kind      DecisionLifetimeKind `json:"kind"                 yaml:"kind"`
+	TTL       string               `json:"ttl,omitempty"        yaml:"ttl,omitempty"`
+	NotBefore string               `json:"not_before,omitempty" yaml:"not_before,omitempty"`
+	ExpiresAt string               `json:"expires_at"           yaml:"expires_at"`
+}
+
 // DecisionBinding is the exact normalized authorization request evaluated by
 // a decision. It lets a consumer verify structured action, target, actor, and
 // context fields without parsing reason or diagnostic prose.
@@ -232,11 +266,20 @@ type DecisionBinding struct {
 	RequestDigest string         `json:"request_digest"           yaml:"request_digest"`
 }
 
+// requestDigestMaterial is the exact tuple hashed for §6.4.2 replay. Request
+// id, policy version, and caring_context are excluded: id is correlation, the
+// version is provenance, and caring_context is an input-claim digest.
+type requestDigestMaterial struct {
+	Tenant   string         `json:"tenant,omitempty"`
+	Subject  SubjectRef     `json:"subject"`
+	Action   string         `json:"action"`
+	Resource ResourceRef    `json:"resource"`
+	Context  map[string]any `json:"context,omitempty"`
+}
+
 // NewDecisionBinding returns a stable structured binding for the exact request
 // an evaluator consumed.
 func NewDecisionBinding(request CheckRequest) *DecisionBinding {
-	data, _ := json.Marshal(request)
-	sum := sha256.Sum256(data)
 	contextCopy := make(map[string]any, len(request.Context))
 	for key, value := range request.Context {
 		contextCopy[key] = value
@@ -247,7 +290,131 @@ func NewDecisionBinding(request CheckRequest) *DecisionBinding {
 		Action:        request.Action,
 		Resource:      request.Resource,
 		Context:       contextCopy,
-		RequestDigest: "sha256:" + hex.EncodeToString(sum[:]),
+		RequestDigest: RequestDigest(request),
+	}
+}
+
+// RequestDigest is the mechanical §6.4.2 replay test: SHA-256 over canonical
+// JSON of tenant, subject, action, resource, and context.
+func RequestDigest(request CheckRequest) string {
+	return CanonicalDigest(requestDigestMaterial{
+		Tenant:   request.Tenant,
+		Subject:  request.Subject,
+		Action:   request.Action,
+		Resource: request.Resource,
+		Context:  request.Context,
+	})
+}
+
+// CanonicalDigest returns "sha256:" plus the hex SHA-256 of canonical JSON.
+// encoding/json sorts map keys, so two equal Go values agree.
+func CanonicalDigest(value any) string {
+	data, err := json.Marshal(value)
+	if err != nil {
+		sum := sha256.Sum256(nil)
+		return "sha256:" + hex.EncodeToString(sum[:])
+	}
+	sum := sha256.Sum256(data)
+	return "sha256:" + hex.EncodeToString(sum[:])
+}
+
+// InputClaimDigests hashes the request-time claim classes the evaluator joined.
+func InputClaimDigests(request CheckRequest) map[string]string {
+	digests := make(map[string]string)
+	if len(request.Context) > 0 {
+		digests["context"] = CanonicalDigest(request.Context)
+	}
+	if request.CaringContext != nil {
+		digests["caring_context"] = CanonicalDigest(request.CaringContext)
+	}
+	if len(digests) == 0 {
+		return nil
+	}
+	return digests
+}
+
+// DecisionCompletion carries evaluator-side inputs used to finish an envelope.
+type DecisionCompletion struct {
+	AllowTTL string
+	Now      time.Time
+}
+
+// CompleteDecision stamps contract version, input-claim digests, decision time,
+// and an explicit allow lifetime. An allow with no stated end becomes a deny.
+func CompleteDecision(envelope *DecisionEnvelope, request CheckRequest, completion DecisionCompletion) {
+	if envelope == nil {
+		return
+	}
+	if envelope.ContractVersion == "" {
+		envelope.ContractVersion = DecisionRecordContractV1
+	}
+	if envelope.Provenance.InputClaimDigests == nil {
+		envelope.Provenance.InputClaimDigests = InputClaimDigests(request)
+	}
+	ApplyAllowLifetime(envelope, completion.AllowTTL, completion.Now)
+}
+
+// ParseAllowTTL resolves a package-declared TTL. ok is false when the allow
+// would have no stated end. Invalid strings return an error so package
+// validation can reject them.
+func ParseAllowTTL(declared string) (time.Duration, error) {
+	trimmed := strings.TrimSpace(declared)
+	if trimmed == "" {
+		return DefaultAllowTTL, nil
+	}
+	if strings.EqualFold(trimmed, "none") {
+		return 0, nil
+	}
+	ttl, err := time.ParseDuration(trimmed)
+	if err != nil {
+		return 0, fmt.Errorf("allow_ttl %q is not a Go duration: %w", declared, err)
+	}
+	if ttl <= 0 {
+		return 0, nil
+	}
+	return ttl, nil
+}
+
+// ApplyAllowLifetime sets DecisionTime and, for allows, an explicit TTL. A
+// missing or zero TTL denies the allow rather than mint a standing grant.
+func ApplyAllowLifetime(envelope *DecisionEnvelope, declaredTTL string, now time.Time) {
+	if envelope == nil {
+		return
+	}
+	if now.IsZero() {
+		now = time.Now().UTC()
+	} else {
+		now = now.UTC()
+	}
+	if envelope.Provenance.DecisionTime == "" {
+		envelope.Provenance.DecisionTime = now.Format(time.RFC3339)
+	}
+	if envelope.Effect != DecisionEffectAllow {
+		return
+	}
+	ttl, err := ParseAllowTTL(declaredTTL)
+	if err != nil || ttl <= 0 {
+		if envelope.Diagnostics == nil {
+			envelope.Diagnostics = map[string]any{}
+		}
+		if envelope.Reason != "" {
+			envelope.Diagnostics["unstated_allow_reason"] = envelope.Reason
+		}
+		envelope.Effect = DecisionEffectDeny
+		envelope.Reason = ReasonAllowLifetimeUnstated
+		envelope.MatchedRule = ReasonAllowLifetimeUnstated
+		envelope.Lifetime = nil
+		return
+	}
+	display := strings.TrimSpace(declaredTTL)
+	if display == "" {
+		display = "15m"
+	}
+	envelope.Lifetime = &DecisionLifetime{
+		Kind:      DecisionLifetimeTTL,
+		TTL:       display,
+		NotBefore: now.Format(time.RFC3339),
+		ExpiresAt: now.Add(ttl).Format(time.RFC3339),
 	}
 }
 
@@ -306,12 +473,15 @@ type Obligation struct {
 
 // DecisionProvenance captures evaluator and policy provenance.
 type DecisionProvenance struct {
-	Evaluator     string `json:"evaluator"                  yaml:"evaluator"`
-	Mode          string `json:"mode"                       yaml:"mode"`
-	PolicyPackage string `json:"policy_package,omitempty"   yaml:"policy_package,omitempty"`
-	PolicyVersion string `json:"policy_version,omitempty"   yaml:"policy_version,omitempty"`
-	DirectoryETag string `json:"directory_etag,omitempty"   yaml:"directory_etag,omitempty"`
-	DecisionTime  string `json:"decision_time,omitempty"    yaml:"decision_time,omitempty"`
+	Evaluator              string            `json:"evaluator"                            yaml:"evaluator"`
+	Mode                   string            `json:"mode"                                 yaml:"mode"`
+	PolicyPackage          string            `json:"policy_package,omitempty"             yaml:"policy_package,omitempty"`
+	PolicyVersion          string            `json:"policy_version,omitempty"             yaml:"policy_version,omitempty"`
+	PolicyPackageDigest    string            `json:"policy_package_digest,omitempty"      yaml:"policy_package_digest,omitempty"`
+	RegistrySnapshotDigest string            `json:"registry_snapshot_digest,omitempty"   yaml:"registry_snapshot_digest,omitempty"`
+	DirectoryETag          string            `json:"directory_etag,omitempty"             yaml:"directory_etag,omitempty"`
+	InputClaimDigests      map[string]string `json:"input_claim_digests,omitempty"        yaml:"input_claim_digests,omitempty"`
+	DecisionTime           string            `json:"decision_time,omitempty"              yaml:"decision_time,omitempty"`
 }
 
 // CaringDecisionMetadata carries CARING descriptor and conformance details in
diff --git a/pkg/api/canonical_test.go b/pkg/api/canonical_test.go
index 309db7e..640794f 100644
--- a/pkg/api/canonical_test.go
+++ b/pkg/api/canonical_test.go
@@ -5,7 +5,9 @@ import (
 	"os"
 	"path/filepath"
 	"reflect"
+	"strings"
 	"testing"
+	"time"
 
 	"gopkg.in/yaml.v3"
 
@@ -71,6 +73,12 @@ func TestDecisionAndAuditExamplesParse(t *testing.T) {
 	if decision.Effect != api.DecisionEffectAllow {
 		t.Errorf("Decision.Effect = %q; want allow", decision.Effect)
 	}
+	if decision.Lifetime == nil || decision.Lifetime.Kind != api.DecisionLifetimeTTL {
+		t.Fatalf("Decision.Lifetime = %+v; want ttl", decision.Lifetime)
+	}
+	if decision.ContractVersion != api.DecisionRecordContractV1 {
+		t.Errorf("Decision.ContractVersion = %q", decision.ContractVersion)
+	}
 	if decision.Caring == nil || decision.Caring.Profile != api.CaringProfileCaring040RC2 {
 		t.Fatalf("Decision.Caring = %+v; want CARING profile metadata", decision.Caring)
 	}
@@ -112,6 +120,80 @@ func TestActionAuthorizationExampleParses(t *testing.T) {
 	}
 }
 
+func TestRequestDigestIgnoresIDAndChangesWithAction(t *testing.T) {
+	request := api.CheckRequest{
+		ID:      "check:one",
+		Tenant:  "tenant:alpha",
+		Subject: api.SubjectRef{ID: "user:alice", Type: api.SubjectTypeHuman},
+		Action:  "read",
+		Resource: api.ResourceRef{
+			ID:     "document:internal-note",
+			Type:   "document",
+			System: "markitect-tool",
+		},
+		Context: map[string]any{"purpose": "project-delivery"},
+	}
+	first := api.RequestDigest(request)
+	if !strings.HasPrefix(first, "sha256:") || len(first) != len("sha256:")+64 {
+		t.Fatalf("RequestDigest = %q", first)
+	}
+
+	same := request
+	same.ID = "check:other"
+	same.PolicyVersion = "v9"
+	if api.RequestDigest(same) != first {
+		t.Fatal("digest changed when only id/policy_version changed")
+	}
+
+	changed := request
+	changed.Action = "destroy"
+	if api.RequestDigest(changed) == first {
+		t.Fatal("digest did not change when action changed")
+	}
+
+	binding := api.NewDecisionBinding(request)
+	if binding.RequestDigest != first {
+		t.Fatalf("binding digest %q != RequestDigest %q", binding.RequestDigest, first)
+	}
+}
+
+func TestApplyAllowLifetimeDefaultDeclaredAndNone(t *testing.T) {
+	now := mustParseTime(t, "2026-08-29T12:00:00Z")
+
+	allow := api.DecisionEnvelope{Effect: api.DecisionEffectAllow, Reason: "reader_relation"}
+	api.ApplyAllowLifetime(&allow, "", now)
+	if allow.Effect != api.DecisionEffectAllow || allow.Lifetime == nil {
+		t.Fatalf("default TTL denied or skipped: %+v", allow)
+	}
+	if allow.Lifetime.TTL != "15m" || allow.Lifetime.ExpiresAt != "2026-08-29T12:15:00Z" {
+		t.Fatalf("default lifetime = %+v", allow.Lifetime)
+	}
+
+	declared := api.DecisionEnvelope{Effect: api.DecisionEffectAllow, Reason: "reader_relation"}
+	api.ApplyAllowLifetime(&declared, "5m", now)
+	if declared.Lifetime == nil || declared.Lifetime.TTL != "5m" || declared.Lifetime.ExpiresAt != "2026-08-29T12:05:00Z" {
+		t.Fatalf("declared lifetime = %+v", declared.Lifetime)
+	}
+
+	unstated := api.DecisionEnvelope{Effect: api.DecisionEffectAllow, Reason: "reader_relation"}
+	api.ApplyAllowLifetime(&unstated, "none", now)
+	if unstated.Effect != api.DecisionEffectDeny || unstated.Reason != api.ReasonAllowLifetimeUnstated {
+		t.Fatalf("unstated allow = %+v; want deny", unstated)
+	}
+	if unstated.Lifetime != nil {
+		t.Fatalf("unstated allow still has lifetime %+v", unstated.Lifetime)
+	}
+}
+
+func mustParseTime(t *testing.T, value string) time.Time {
+	t.Helper()
+	parsed, err := time.Parse(time.RFC3339, value)
+	if err != nil {
+		t.Fatalf("parse time %q: %v", value, err)
+	}
+	return parsed
+}
+
 func TestSchemaFilesAreJSON(t *testing.T) {
 	schemaDir := filepath.Join("..", "..", "schemas")
 	entries, err := os.ReadDir(schemaDir)
diff --git a/schemas/README.md b/schemas/README.md
index f01862b..a3f23ab 100644
--- a/schemas/README.md
+++ b/schemas/README.md
@@ -11,7 +11,7 @@ JSON Schema definitions for flex-auth's canonical artefacts:
 - `policy_package.schema.json`
 - `policy_fixture.schema.json`
 - `check_request.schema.json`
-- `decision_envelope.schema.json`
+- `decision_envelope.schema.json` — published decision-record contract (`flex-auth.decision-record.v1`; see `docs/decision-record-contract.md`)
 - `action_authorization.schema.json`
 - `audit_event.schema.json`
 
diff --git a/schemas/decision_envelope.schema.json b/schemas/decision_envelope.schema.json
index b78466a..b653ac2 100644
--- a/schemas/decision_envelope.schema.json
+++ b/schemas/decision_envelope.schema.json
@@ -2,11 +2,13 @@
   "$schema": "https://json-schema.org/draft/2020-12/schema",
   "$id": "https://flex-auth.netkingdom/schemas/decision_envelope.schema.json",
   "title": "DecisionEnvelope",
+  "description": "Published flex-auth decision-record contract (flex-auth.decision-record.v1). This is the PDP's output artifact under security-layer-model_v0.7 §17.",
   "type": "object",
   "additionalProperties": false,
   "required": ["id", "effect", "resource", "subject", "provenance"],
   "properties": {
     "id": {"type": "string", "minLength": 1},
+    "contract_version": {"const": "flex-auth.decision-record.v1"},
     "request_id": {"type": "string", "minLength": 1},
     "effect": {"enum": ["allow", "deny", "redact", "audit_only", "not_applicable"]},
     "reason": {"type": "string"},
@@ -15,11 +17,18 @@
     "resource": {"$ref": "https://flex-auth.netkingdom/schemas/check_request.schema.json#/$defs/resource_ref"},
     "subject": {"$ref": "https://flex-auth.netkingdom/schemas/check_request.schema.json#/$defs/subject_ref"},
     "binding": {"$ref": "#/$defs/decision_binding"},
+    "lifetime": {"$ref": "#/$defs/lifetime"},
     "obligations": {"type": "array", "items": {"$ref": "#/$defs/obligation"}},
     "diagnostics": {"type": "object", "additionalProperties": true},
     "provenance": {"$ref": "#/$defs/provenance"},
     "caring": {"$ref": "#/$defs/caring_decision_metadata"}
   },
+  "allOf": [
+    {
+      "if": {"properties": {"effect": {"const": "allow"}}, "required": ["effect"]},
+      "then": {"required": ["lifetime"]}
+    }
+  ],
   "$defs": {
     "decision_binding": {
       "type": "object",
@@ -43,6 +52,17 @@
         "parameters": {"type": "object", "additionalProperties": true}
       }
     },
+    "lifetime": {
+      "type": "object",
+      "additionalProperties": false,
+      "required": ["kind", "expires_at"],
+      "properties": {
+        "kind": {"enum": ["ttl"]},
+        "ttl": {"type": "string", "minLength": 1},
+        "not_before": {"type": "string", "minLength": 1},
+        "expires_at": {"type": "string", "minLength": 1}
+      }
+    },
     "provenance": {
       "type": "object",
       "additionalProperties": false,
@@ -52,7 +72,13 @@
         "mode": {"type": "string", "minLength": 1},
         "policy_package": {"type": "string", "minLength": 1},
         "policy_version": {"type": "string", "minLength": 1},
+        "policy_package_digest": {"type": "string", "pattern": "^sha256:[0-9a-f]{64}$"},
+        "registry_snapshot_digest": {"type": "string", "pattern": "^sha256:[0-9a-f]{64}$"},
         "directory_etag": {"type": "string", "minLength": 1},
+        "input_claim_digests": {
+          "type": "object",
+          "additionalProperties": {"type": "string", "pattern": "^sha256:[0-9a-f]{64}$"}
+        },
         "decision_time": {"type": "string", "minLength": 1}
       }
     },
diff --git a/schemas/policy_package.schema.json b/schemas/policy_package.schema.json
index f7c2600..f52f3cf 100644
--- a/schemas/policy_package.schema.json
+++ b/schemas/policy_package.schema.json
@@ -25,7 +25,12 @@
     },
     "caring": {"$ref": "#/$defs/caring_policy_metadata"},
     "activation": {"type": "object", "additionalProperties": true},
-    "metadata": {"type": "object", "additionalProperties": true}
+    "metadata": {"type": "object", "additionalProperties": true},
+    "allow_ttl": {
+      "type": "string",
+      "minLength": 1,
+      "description": "Go duration bounding every allow this package produces (e.g. 15m). Omit to use the engine default of 15m. The values none and 0s mean no stated end; the engine denies those allows."
+    }
   },
   "$defs": {
     "caring_policy_metadata": {
diff --git a/tools/check_layer_conformance.go b/tools/check_layer_conformance.go
new file mode 100644
index 0000000..bf492ef
--- /dev/null
+++ b/tools/check_layer_conformance.go
@@ -0,0 +1,28 @@
+// Command check_layer_conformance asserts the INTENT.md layer declaration
+// and that no Tooling client exists in production Go sources.
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/netkingdom/flex-auth/internal/layer"
+)
+
+func main() {
+	root, err := os.Getwd()
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(2)
+	}
+	if _, err := os.Stat(filepath.Join(root, "INTENT.md")); err != nil {
+		fmt.Fprintf(os.Stderr, "INTENT.md not found in %s\n", root)
+		os.Exit(2)
+	}
+	if err := layer.Check(root); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+	fmt.Println("PASS — Engine/PDP declaration parses; no Tooling client in the tree.")
+}
diff --git a/workplans/FLEX-WP-0019-layer-model-conformance.md b/workplans/FLEX-WP-0019-layer-model-conformance.md
index 6c0b85e..27d8914 100644
--- a/workplans/FLEX-WP-0019-layer-model-conformance.md
+++ b/workplans/FLEX-WP-0019-layer-model-conformance.md
@@ -4,13 +4,13 @@ type: workplan
 title: "Layer model v0.7 conformance: provenance, lifetimes, deadlines, and the decision contract"
 domain: infotech
 repo: flex-auth
-status: ready
-owner: codex
+status: finished
+owner: grok
 topic_slug: netkingdom
 planning_priority: P1
 planning_order: 119
 created: "2026-08-29"
-updated: "2026-08-29"
+updated: "2026-09-03"
 reviewed_at: "2026-08-29"
 reviewed_against_commit: "d402408"
 reviewed_note: >-
@@ -54,7 +54,7 @@ would publish a number nobody can check.
 
 ```task
 id: FLEX-WP-0019-T01
-status: todo
+status: done
 priority: medium
 state_hub_task_id: "f72b1305-114e-5ba2-b84c-f6cc0b524178"
 ```
@@ -72,7 +72,7 @@ Closes G1's remaining half. Wire it into `make test`.
 
 ```task
 id: FLEX-WP-0019-T02
-status: todo
+status: done
 priority: high
 state_hub_task_id: "7a980074-8488-5ab1-9202-60878adb261d"
 ```
@@ -94,7 +94,7 @@ snapshot changes the digest and that two decisions over the same snapshot agree.
 
 ```task
 id: FLEX-WP-0019-T03
-status: todo
+status: done
 priority: high
 state_hub_task_id: "9d9c0e7a-56e2-5c71-9110-cea973243c22"
 ```
@@ -115,7 +115,7 @@ appear in the decision record and the published schema.
 
 ```task
 id: FLEX-WP-0019-T04
-status: todo
+status: done
 priority: high
 state_hub_task_id: "d5917b24-2efb-503e-9a9d-837702cafc1c"
 ```
@@ -134,7 +134,7 @@ identify the snapshot a decision read. Publish as
 
 ```task
 id: FLEX-WP-0019-T05
-status: todo
+status: done
 priority: medium
 state_hub_task_id: "f7f501d7-6862-5542-88f7-78b704524706"
 ```
@@ -154,7 +154,7 @@ flex-auth's.
 
 ```task
 id: FLEX-WP-0019-T06
-status: todo
+status: done
 priority: medium
 state_hub_task_id: "bc109ee3-14b0-5603-a655-0d7376c2a41c"
 ```
@@ -168,3 +168,16 @@ Publish what it is computed over, what normalization applies, its stability
 guarantees across versions, and worked examples of a permitted retry and a
 refused replay. Consumers cannot honour §6.4.2 against an undocumented digest,
 and negative caching under §6.4.2 needs the same guidance.
+
+## Closeout
+
+Finished 2026-09-03. `go test -race ./...` and `go run ./tools/check_layer_conformance.go` pass.
+
+| Task | Landed as |
+| --- | --- |
+| T01 | `internal/layer`, `tools/check_layer_conformance.go`, wired into `make test` |
+| T02 | `registry.Store.Digest` in `DecisionProvenance.registry_snapshot_digest` on standalone and delegated envelopes |
+| T03 | Policy `allow_ttl`, engine default `15m`, deny `allow_lifetime_unstated` |
+| T04 | `docs/decision-input-freshness.md`, referenced from `INTENT.md` |
+| T05 | `flex-auth.decision-record.v1` in schema + `docs/decision-record-contract.md` |
+| T06 | `docs/canonical-request-digest.md`; digest is tenant/subject/action/resource/context |