diff --git a/docs/roadmap/implementation.md b/docs/roadmap/implementation.md
index 2cc2681..be646f7 100644
--- a/docs/roadmap/implementation.md
+++ b/docs/roadmap/implementation.md
@@ -287,6 +287,9 @@ Scope: private scoped-state transformations built on Stage 4's resolution helper
 Validation: focused collection-policy tests and the everyday check. This stage
 must not add path-existence, shape, nullability, or global YAML final-check rules.
 
+**Completion:** Implemented and verified with focused collection-policy tests,
+`go test -race ./internal/engine`, and `./scripts/check.sh`.
+
 ## Stage 6 — Implement The Shared Sequence Operations
 
 Scope: a pure document-level combination helper, not separate implementations
diff --git a/internal/engine/collection_policy.go b/internal/engine/collection_policy.go
index 0a372d0..bb60aac 100644
--- a/internal/engine/collection_policy.go
+++ b/internal/engine/collection_policy.go
@@ -7,6 +7,8 @@ type collectionPolicy struct {
 	explicitMode        sequenceMode
 	explicitModePresent bool
 	modeLocation        *Location
+	recordOrder         []*collectionRecordOwner
+	recordPolicies      map[*collectionRecordOwner]collectionPolicyScope
 }
 
 type collectionPolicyResolution struct {
diff --git a/internal/engine/collection_policy_state.go b/internal/engine/collection_policy_state.go
new file mode 100644
index 0000000..fde8b47
--- /dev/null
+++ b/internal/engine/collection_policy_state.go
@@ -0,0 +1,242 @@
+package engine
+
+import (
+	"sort"
+
+	"gitea.maximumdirect.net/eric/ConfigKit/internal/document"
+)
+
+type collectionPolicyScope struct {
+	collections map[string]collectionPolicyEntry
+}
+
+type collectionPolicyEntry struct {
+	destination Path
+	policy      collectionPolicy
+}
+
+type collectionRecordPolicy struct {
+	owner *collectionRecordOwner
+	scope collectionPolicyScope
+}
+
+// The nonzero field ensures simultaneously live record owners have distinct
+// addresses. The token is per-record ownership, not a source or identity key.
+type collectionRecordOwner struct {
+	marker byte
+}
+
+type projectedCollectionPolicy struct {
+	path   Path
+	policy collectionPolicy
+}
+
+func newCollectionRecordPolicy() collectionRecordPolicy {
+	return collectionRecordPolicy{owner: &collectionRecordOwner{marker: 1}}
+}
+
+func retainedCollectionRecordPolicy(record collectionRecordPolicy) collectionRecordPolicy {
+	return collectionRecordPolicy{
+		owner: record.owner,
+		scope: cloneCollectionPolicyScope(record.scope),
+	}
+}
+
+func replacedCollectionRecordPolicy() collectionRecordPolicy {
+	return newCollectionRecordPolicy()
+}
+
+func (policy *collectionPolicy) setRecordPolicy(record collectionRecordPolicy) {
+	if record.owner == nil {
+		record.owner = newCollectionRecordPolicy().owner
+	}
+	if policy.recordPolicies == nil {
+		policy.recordPolicies = make(map[*collectionRecordOwner]collectionPolicyScope)
+	}
+	if _, exists := policy.recordPolicies[record.owner]; !exists {
+		policy.recordOrder = append(policy.recordOrder, record.owner)
+	}
+	policy.recordPolicies[record.owner] = cloneCollectionPolicyScope(record.scope)
+}
+
+func (policy collectionPolicy) recordPolicyAt(index int) (collectionRecordPolicy, bool) {
+	if index < 0 || index >= len(policy.recordOrder) {
+		return collectionRecordPolicy{}, false
+	}
+	owner := policy.recordOrder[index]
+	scope, ok := policy.recordPolicies[owner]
+	if !ok {
+		return collectionRecordPolicy{}, false
+	}
+	return collectionRecordPolicy{owner: owner, scope: cloneCollectionPolicyScope(scope)}, true
+}
+
+func collectionPolicyForReplacement(lower *collectionPolicy, current collectionPolicy) collectionPolicy {
+	result := cloneCollectionPolicy(current)
+	if !current.explicitModePresent && lower != nil && lower.explicitModePresent {
+		result.explicitMode = lower.explicitMode
+		result.explicitModePresent = true
+		result.modeLocation = cloneLocation(lower.modeLocation)
+	}
+	return result
+}
+
+// collectionPolicyWithoutValue keeps identity and record ownership because no
+// collection value was replaced. A key-only declaration can remain pending
+// when no sequence is present, or validate the retained sequence immediately.
+func collectionPolicyWithoutValue(
+	lower *collectionPolicy,
+	current collectionPolicy,
+	retainedValue *document.Node,
+	path Path,
+) (collectionPolicy, []Diagnostic) {
+	result := collectionPolicy{}
+	if lower != nil {
+		result = cloneCollectionPolicy(*lower)
+	}
+	if lower != nil && lower.identityPresent && current.identityPresent && !equalSequenceIdentityFields(lower.identityFields, current.identityFields) {
+		return collectionPolicy{}, []Diagnostic{collectionPolicyConflictDiagnostic(
+			path, current.identityLocation, lower.identityLocation,
+			"collection identity declaration conflicts with retained identity",
+		)}
+	}
+	if current.identityPresent {
+		result.identityFields = cloneStrings(current.identityFields)
+		result.identityPresent = true
+		result.identityLocation = cloneLocation(current.identityLocation)
+	}
+	if current.explicitModePresent {
+		result.explicitMode = current.explicitMode
+		result.explicitModePresent = true
+		result.modeLocation = cloneLocation(current.modeLocation)
+	}
+	if current.identityPresent && retainedValue != nil && retainedValue.Kind == document.Sequence {
+		_, diagnostics := validateSequenceIdentity(retainedValue, path, result.identityFields, sequenceIdentityDiagnosticCodes{
+			invalid: CodeSequenceInvalid, conflict: CodeSequenceConflict,
+		})
+		if len(diagnostics) != 0 {
+			return collectionPolicy{}, diagnostics
+		}
+	}
+	return result, nil
+}
+
+func (scope *collectionPolicyScope) set(destination Path, policy collectionPolicy) {
+	if scope.collections == nil {
+		scope.collections = make(map[string]collectionPolicyEntry)
+	}
+	scope.collections[destination.String()] = collectionPolicyEntry{
+		destination: destination.clone(), policy: cloneCollectionPolicy(policy),
+	}
+}
+
+func (scope collectionPolicyScope) at(destination Path) (collectionPolicy, bool) {
+	entry, ok := scope.collections[destination.String()]
+	if !ok {
+		return collectionPolicy{}, false
+	}
+	return cloneCollectionPolicy(entry.policy), true
+}
+
+// retireCollectionPoliciesAtOrBelow clears YAML identity and record-owned state
+// below a replaced ancestor while retaining independently scoped explicit modes.
+func (scope *collectionPolicyScope) retireCollectionPoliciesAtOrBelow(ancestor Path) {
+	if scope == nil {
+		return
+	}
+	for key, entry := range scope.collections {
+		if !pathHasPrefix(entry.destination, ancestor) {
+			continue
+		}
+		entry.policy.identityFields = nil
+		entry.policy.identityPresent = false
+		entry.policy.identityLocation = nil
+		entry.policy.recordOrder = nil
+		entry.policy.recordPolicies = nil
+		scope.collections[key] = entry
+	}
+}
+
+func projectCollectionPolicyScope(scope collectionPolicyScope, prefix Path) []projectedCollectionPolicy {
+	keys := make([]string, 0, len(scope.collections))
+	for key := range scope.collections {
+		keys = append(keys, key)
+	}
+	sort.Strings(keys)
+	var projected []projectedCollectionPolicy
+	for _, key := range keys {
+		entry := scope.collections[key]
+		concrete := appendDestination(prefix, entry.destination)
+		projected = append(projected, projectedCollectionPolicy{path: concrete, policy: cloneCollectionPolicy(entry.policy)})
+		for index, owner := range entry.policy.recordOrder {
+			if recordScope, ok := entry.policy.recordPolicies[owner]; ok {
+				projected = append(projected, projectCollectionPolicyScope(recordScope, concrete.Index(index))...)
+			}
+		}
+	}
+	return projected
+}
+
+func cloneCollectionPolicyScope(scope collectionPolicyScope) collectionPolicyScope {
+	if scope.collections == nil {
+		return collectionPolicyScope{}
+	}
+	cloned := collectionPolicyScope{collections: make(map[string]collectionPolicyEntry, len(scope.collections))}
+	for key, entry := range scope.collections {
+		cloned.collections[key] = collectionPolicyEntry{
+			destination: entry.destination.clone(), policy: cloneCollectionPolicy(entry.policy),
+		}
+	}
+	return cloned
+}
+
+func cloneCollectionPolicyScopeForInheritance(scope collectionPolicyScope) collectionPolicyScope {
+	if scope.collections == nil {
+		return collectionPolicyScope{}
+	}
+	cloned := collectionPolicyScope{collections: make(map[string]collectionPolicyEntry, len(scope.collections))}
+	for key, entry := range scope.collections {
+		cloned.collections[key] = collectionPolicyEntry{
+			destination: entry.destination.clone(), policy: cloneCollectionPolicyForInheritance(entry.policy),
+		}
+	}
+	return cloned
+}
+
+func cloneCollectionPolicy(policy collectionPolicy) collectionPolicy {
+	cloned := policy
+	cloned.identityFields = cloneStrings(policy.identityFields)
+	cloned.identityLocation = cloneLocation(policy.identityLocation)
+	cloned.modeLocation = cloneLocation(policy.modeLocation)
+	if policy.recordOrder != nil {
+		cloned.recordOrder = append([]*collectionRecordOwner(nil), policy.recordOrder...)
+	}
+	if policy.recordPolicies != nil {
+		cloned.recordPolicies = make(map[*collectionRecordOwner]collectionPolicyScope, len(policy.recordPolicies))
+		for owner, scope := range policy.recordPolicies {
+			cloned.recordPolicies[owner] = cloneCollectionPolicyScope(scope)
+		}
+	}
+	return cloned
+}
+
+func cloneCollectionPolicyForInheritance(policy collectionPolicy) collectionPolicy {
+	cloned := policy
+	cloned.identityFields = cloneStrings(policy.identityFields)
+	cloned.identityLocation = cloneLocation(policy.identityLocation)
+	cloned.modeLocation = cloneLocation(policy.modeLocation)
+	if policy.recordOrder != nil {
+		cloned.recordOrder = make([]*collectionRecordOwner, 0, len(policy.recordOrder))
+	}
+	if policy.recordPolicies != nil {
+		cloned.recordPolicies = make(map[*collectionRecordOwner]collectionPolicyScope, len(policy.recordPolicies))
+		for _, sourceOwner := range policy.recordOrder {
+			owner := newCollectionRecordPolicy().owner
+			cloned.recordOrder = append(cloned.recordOrder, owner)
+			if sourceScope, ok := policy.recordPolicies[sourceOwner]; ok {
+				cloned.recordPolicies[owner] = cloneCollectionPolicyScopeForInheritance(sourceScope)
+			}
+		}
+	}
+	return cloned
+}
diff --git a/internal/engine/collection_policy_state_test.go b/internal/engine/collection_policy_state_test.go
new file mode 100644
index 0000000..8c71c3a
--- /dev/null
+++ b/internal/engine/collection_policy_state_test.go
@@ -0,0 +1,292 @@
+package engine
+
+import (
+	"reflect"
+	"testing"
+
+	"gitea.maximumdirect.net/eric/ConfigKit/internal/document"
+)
+
+func TestCollectionPolicyWithoutValueRetainsIdentityAndMode(t *testing.T) {
+	lower := collectionPolicy{
+		identityFields:      []string{"id"},
+		identityPresent:     true,
+		explicitMode:        sequenceModeAppend,
+		explicitModePresent: true,
+	}
+	lower.setRecordPolicy(newCollectionRecordPolicy())
+	current := collectionPolicy{explicitMode: sequenceModeReplace, explicitModePresent: true}
+	retained, diagnostics := collectionPolicyWithoutValue(&lower, current, nil, Keys("prompts"))
+	if len(diagnostics) != 0 || !retained.identityPresent || !reflect.DeepEqual(retained.identityFields, []string{"id"}) {
+		t.Fatalf("no-value replace reset identity: %#v, %#v", retained, diagnostics)
+	}
+	if retained.explicitMode != sequenceModeReplace || !retained.explicitModePresent || len(retained.recordOrder) != 1 {
+		t.Fatalf("no-value policy update lost mode or record ownership: %#v", retained)
+	}
+	retainedRecord, _ := retained.recordPolicyAt(0)
+	lowerRecord, _ := lower.recordPolicyAt(0)
+	if retainedRecord.owner != lowerRecord.owner {
+		t.Fatal("no-value policy update changed record ownership")
+	}
+}
+
+func TestCollectionPolicyWithoutValueLeavesAbsentAndNonSequenceDestinationsUnconstrained(t *testing.T) {
+	current := collectionPolicy{identityFields: []string{"id"}, identityPresent: true}
+	for _, value := range []*document.Node{nil, parsePolicyNode(t, "value: scalar\n").Mapping[0].Value} {
+		retained, diagnostics := collectionPolicyWithoutValue(nil, current, value, Keys("prompts"))
+		if len(diagnostics) != 0 || !retained.identityPresent || !reflect.DeepEqual(retained.identityFields, []string{"id"}) {
+			t.Fatalf("pending identity at absent/non-sequence destination = %#v, %#v", retained, diagnostics)
+		}
+	}
+}
+
+func TestCollectionPolicyWithoutValueValidatesRetainedSequenceImmediately(t *testing.T) {
+	current := collectionPolicy{identityFields: []string{"id"}, identityPresent: true}
+	valid := parsePolicyNode(t, "items: [{id: one}, {id: two}]\n").Mapping[0].Value
+	retained, diagnostics := collectionPolicyWithoutValue(nil, current, valid, Keys("prompts"))
+	if len(diagnostics) != 0 || !retained.identityPresent {
+		t.Fatalf("valid retained records were rejected: %#v, %#v", retained, diagnostics)
+	}
+
+	invalid := parsePolicyNode(t, "items: [{name: missing-id}]\n").Mapping[0].Value
+	retained, diagnostics = collectionPolicyWithoutValue(nil, current, invalid, Keys("prompts"))
+	if !reflect.DeepEqual(retained, collectionPolicy{}) || len(diagnostics) != 1 || diagnostics[0].Code != CodeSequenceInvalid || diagnostics[0].Path.String() != "/prompts/0/id" {
+		t.Fatalf("invalid retained records = %#v, %#v", retained, diagnostics)
+	}
+}
+
+func TestCollectionPolicyWithoutValueRejectsIdentityChange(t *testing.T) {
+	lower := collectionPolicy{identityFields: []string{"id"}, identityPresent: true}
+	current := collectionPolicy{identityFields: []string{"name"}, identityPresent: true}
+	retained, diagnostics := collectionPolicyWithoutValue(&lower, current, nil, Keys("prompts"))
+	if !reflect.DeepEqual(retained, collectionPolicy{}) || len(diagnostics) != 1 || diagnostics[0].Code != CodeSequenceConflict {
+		t.Fatalf("no-value identity change = %#v, %#v", retained, diagnostics)
+	}
+}
+
+func TestCollectionPolicyLifetimePersistenceAndReplacementTable(t *testing.T) {
+	tests := []struct {
+		name            string
+		current         collectionPolicy
+		replaceValue    bool
+		wantIdentity    []string
+		wantIdentitySet bool
+		wantMode        sequenceMode
+		wantRecords     int
+	}{
+		{
+			name: "mode-only replace declaration does not reset retained identity",
+			current: collectionPolicy{
+				explicitMode: sequenceModeReplace, explicitModePresent: true,
+			},
+			wantIdentity: []string{"id"}, wantIdentitySet: true,
+			wantMode: sequenceModeReplace, wantRecords: 1,
+		},
+		{
+			name:            "whole-sequence replacement resets lower identity",
+			replaceValue:    true,
+			wantIdentitySet: false,
+			wantMode:        sequenceModeAppend,
+			wantRecords:     0,
+		},
+		{
+			name:            "replacement can establish a new identity",
+			current:         collectionPolicy{identityFields: []string{"name"}, identityPresent: true},
+			replaceValue:    true,
+			wantIdentity:    []string{"name"},
+			wantIdentitySet: true,
+			wantMode:        sequenceModeAppend,
+			wantRecords:     0,
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			lower := collectionPolicy{
+				identityFields: []string{"id"}, identityPresent: true,
+				explicitMode: sequenceModeAppend, explicitModePresent: true,
+			}
+			lower.setRecordPolicy(newCollectionRecordPolicy())
+			var got collectionPolicy
+			if test.replaceValue {
+				got = collectionPolicyForReplacement(&lower, test.current)
+			} else {
+				var diagnostics []Diagnostic
+				got, diagnostics = collectionPolicyWithoutValue(&lower, test.current, nil, Keys("prompts"))
+				if len(diagnostics) != 0 {
+					t.Fatalf("policy diagnostics = %#v", diagnostics)
+				}
+			}
+			if got.identityPresent != test.wantIdentitySet || !reflect.DeepEqual(got.identityFields, test.wantIdentity) || got.explicitMode != test.wantMode || len(got.recordOrder) != test.wantRecords {
+				t.Fatalf("transition result = %#v", got)
+			}
+		})
+	}
+}
+
+func TestCollectionPolicyValueReplacementResetsIdentityButRetainsExplicitMode(t *testing.T) {
+	lower := collectionPolicy{
+		identityFields:      []string{"id"},
+		identityPresent:     true,
+		explicitMode:        sequenceModeAppend,
+		explicitModePresent: true,
+	}
+	lower.setRecordPolicy(newCollectionRecordPolicy())
+	current := collectionPolicy{identityFields: []string{"name"}, identityPresent: true}
+	replaced := collectionPolicyForReplacement(&lower, current)
+	if !replaced.identityPresent || !reflect.DeepEqual(replaced.identityFields, []string{"name"}) {
+		t.Fatalf("replacement identity was not reset: %#v", replaced)
+	}
+	if replaced.explicitMode != sequenceModeAppend || !replaced.explicitModePresent || len(replaced.recordOrder) != 0 {
+		t.Fatalf("replacement failed to retain explicit mode or retire lower record policy: %#v", replaced)
+	}
+
+	cleared := collectionPolicyForReplacement(&lower, collectionPolicy{})
+	if cleared.identityPresent || len(cleared.identityFields) != 0 || cleared.explicitMode != sequenceModeAppend || !cleared.explicitModePresent {
+		t.Fatalf("replacement without a new key did not clear YAML identity while retaining mode: %#v", cleared)
+	}
+}
+
+func TestCollectionRecordRetentionAndReplacementUseOpaqueOwners(t *testing.T) {
+	oldRecord := newCollectionRecordPolicy()
+	oldRecord.scope.set(Keys("steps"), collectionPolicy{identityFields: []string{"id"}, identityPresent: true})
+	retained := retainedCollectionRecordPolicy(oldRecord)
+	if retained.owner != oldRecord.owner {
+		t.Fatal("retained record did not keep its owner")
+	}
+	if got, ok := retained.scope.at(Keys("steps")); !ok || !got.identityPresent {
+		t.Fatalf("retained record lost its local policy: %#v, %t", got, ok)
+	}
+	if retained.scope.collections["/steps"].policy.identityFields[0] = "changed"; oldRecord.scope.collections["/steps"].policy.identityFields[0] != "id" {
+		t.Fatal("retained record policy aliases its source")
+	}
+
+	// A whole-record replacement at the same list position, even with equal
+	// authored identity/source metadata, receives new ownership and no old rules.
+	replacement := replacedCollectionRecordPolicy()
+	if replacement.owner == oldRecord.owner || len(replacement.scope.collections) != 0 {
+		t.Fatal("replacement record inherited discarded owner policy")
+	}
+}
+
+func TestCollectionPolicyAncestorRetirementPreservesIndependentMode(t *testing.T) {
+	var scope collectionPolicyScope
+	owner := newCollectionRecordPolicy()
+	owner.scope.set(Keys("steps"), collectionPolicy{identityFields: []string{"id"}, identityPresent: true})
+	scope.set(Keys("catalog", "prompts"), collectionPolicyWithRecords(collectionPolicy{
+		identityFields:      []string{"id"},
+		identityPresent:     true,
+		explicitMode:        sequenceModeAppend,
+		explicitModePresent: true,
+	}, owner))
+	scope.retireCollectionPoliciesAtOrBelow(Keys("catalog"))
+	policy, ok := scope.at(Keys("catalog", "prompts"))
+	if !ok || policy.identityPresent || len(policy.recordOrder) != 0 || policy.explicitMode != sequenceModeAppend || !policy.explicitModePresent {
+		t.Fatalf("ancestor retirement = %#v, %t", policy, ok)
+	}
+	reintroduced, diagnostics := collectionPolicyWithoutValue(&policy, collectionPolicy{}, nil, Keys("catalog", "prompts"))
+	if len(diagnostics) != 0 || reintroduced.identityPresent || reintroduced.explicitMode != sequenceModeAppend {
+		t.Fatalf("retired identity was resurrected while mode persisted: %#v, %#v", reintroduced, diagnostics)
+	}
+}
+
+func TestEqualOuterIdentitiesHaveDistinctRecordOwners(t *testing.T) {
+	retained := newCollectionRecordPolicy()
+	replacement := replacedCollectionRecordPolicy()
+	if retained.owner == replacement.owner {
+		t.Fatal("replacement with the same outer identity reused the old owner")
+	}
+	if retained.owner == nil || replacement.owner == nil {
+		t.Fatal("record owner token is missing")
+	}
+}
+
+func TestCollectionPolicyScopesKeepRootAndItemRulesIndependent(t *testing.T) {
+	var root collectionPolicyScope
+	root.set(Keys("steps"), collectionPolicy{identityFields: []string{"root-id"}, identityPresent: true})
+	owner := newCollectionRecordPolicy()
+	owner.scope.set(Keys("steps"), collectionPolicy{identityFields: []string{"item-id"}, identityPresent: true})
+	root.set(Keys("items"), collectionPolicyWithRecords(collectionPolicy{}, owner))
+
+	root.retireCollectionPoliciesAtOrBelow(Keys("steps"))
+	rootPolicy, ok := root.at(Keys("steps"))
+	if !ok || rootPolicy.identityPresent {
+		t.Fatalf("root-local policy was not retired: %#v", rootPolicy)
+	}
+	itemPolicy, ok := root.at(Keys("items"))
+	if !ok || len(itemPolicy.recordOrder) != 1 {
+		t.Fatalf("unrelated item owner disappeared: %#v", itemPolicy)
+	}
+	itemRecord, _ := itemPolicy.recordPolicyAt(0)
+	nested, ok := itemRecord.scope.at(Keys("steps"))
+	if !ok || !nested.identityPresent || !reflect.DeepEqual(nested.identityFields, []string{"item-id"}) {
+		t.Fatalf("item-local policy was coupled to root destination: %#v", nested)
+	}
+}
+
+func TestCollectionPolicyProjectionUsesConcretePlacement(t *testing.T) {
+	first := newCollectionRecordPolicy()
+	first.scope.set(Keys("steps"), collectionPolicy{identityFields: []string{"step"}, identityPresent: true})
+	second := newCollectionRecordPolicy()
+	second.scope.set(Keys("steps"), collectionPolicy{explicitMode: sequenceModeAppend, explicitModePresent: true})
+	var scope collectionPolicyScope
+	scope.set(Keys("items"), collectionPolicyWithRecords(collectionPolicy{}, first, second))
+
+	projected := projectCollectionPolicyScope(scope, Keys("mounted"))
+	if len(projected) != 3 {
+		t.Fatalf("projected policies = %#v", projected)
+	}
+	want := []string{"/mounted/items", "/mounted/items/0/steps", "/mounted/items/1/steps"}
+	for index, policy := range projected {
+		if policy.path.String() != want[index] {
+			t.Fatalf("projected path[%d] = %q, want %q", index, policy.path.String(), want[index])
+		}
+	}
+}
+
+func TestCollectionPolicyInheritanceCopiesOwnersAndState(t *testing.T) {
+	owner := newCollectionRecordPolicy()
+	owner.scope.set(Keys("steps"), collectionPolicy{identityFields: []string{"id"}, identityPresent: true})
+	original := collectionPolicyWithRecords(collectionPolicy{}, owner)
+	copy := cloneCollectionPolicyForInheritance(original)
+	copyOwner := copy.recordOrder[0]
+	if copyOwner == owner.owner {
+		t.Fatal("inheritance copy retained the source record owner")
+	}
+	copy.recordPolicies[copyOwner].collections["/steps"].policy.identityFields[0] = "changed"
+	if owner.scope.collections["/steps"].policy.identityFields[0] != "id" {
+		t.Fatal("inheritance copy aliases source policy")
+	}
+}
+
+func TestAcquisitionScopeCloneOwnsCollectionPolicyCopy(t *testing.T) {
+	owner := newCollectionRecordPolicy()
+	owner.scope.set(Keys("steps"), collectionPolicy{identityFields: []string{"id"}, identityPresent: true})
+	var scope acquisitionScope
+	scope.collectionPolicies.set(Keys("items"), collectionPolicyWithRecords(collectionPolicy{}, owner))
+	cloned := cloneAcquisitionScope(scope)
+	clonedOwner := cloned.collectionPolicies.collections["/items"].policy.recordOrder[0]
+	cloned.collectionPolicies.collections["/items"].policy.recordPolicies[clonedOwner].collections["/steps"].policy.identityFields[0] = "changed"
+	sourceOwner := scope.collectionPolicies.collections["/items"].policy.recordOrder[0]
+	if scope.collectionPolicies.collections["/items"].policy.recordPolicies[sourceOwner].collections["/steps"].policy.identityFields[0] != "id" {
+		t.Fatal("acquisition scope clone aliases collection policy")
+	}
+	if clonedOwner != owner.owner {
+		t.Fatal("acquisition scope clone changed record ownership")
+	}
+}
+
+func collectionPolicyWithRecords(policy collectionPolicy, records ...collectionRecordPolicy) collectionPolicy {
+	for _, record := range records {
+		policy.setRecordPolicy(record)
+	}
+	return policy
+}
+
+func parsePolicyNode(t *testing.T, input string) *document.Node {
+	t.Helper()
+	parsed, diagnostics := parseSource(Bytes("collection-policy-state.yml", []byte(input)), "collection-policy-state", defaultParseLimits())
+	if len(diagnostics) != 0 {
+		t.Fatalf("parse policy value: %#v", diagnostics)
+	}
+	return parsed.document
+}
diff --git a/internal/engine/load_input.go b/internal/engine/load_input.go
index 9054cd7..d4ec6dc 100644
--- a/internal/engine/load_input.go
+++ b/internal/engine/load_input.go
@@ -39,13 +39,17 @@ type acquiredContribution struct {
 // acquisitionScope is the ordered strict mapping scope produced by one input
 // and its ordinary imports.
 type acquisitionScope struct {
-	owner         importNodeKey
-	destination   Path
-	contributions []acquiredContribution
+	owner              importNodeKey
+	destination        Path
+	contributions      []acquiredContribution
+	collectionPolicies collectionPolicyScope
 }
 
 func cloneAcquisitionScope(scope acquisitionScope) acquisitionScope {
-	cloned := acquisitionScope{owner: scope.owner, destination: scope.destination.clone()}
+	cloned := acquisitionScope{
+		owner: scope.owner, destination: scope.destination.clone(),
+		collectionPolicies: cloneCollectionPolicyScope(scope.collectionPolicies),
+	}
 	if scope.contributions != nil {
 		cloned.contributions = make([]acquiredContribution, len(scope.contributions))
 		for index, contribution := range scope.contributions {