diff --git a/docs/cli-interface-flag-migrations.md b/docs/cli-interface-flag-migrations.md
index 74f4d577..76d11608 100644
--- a/docs/cli-interface-flag-migrations.md
+++ b/docs/cli-interface-flag-migrations.md
@@ -122,7 +122,7 @@ scripts/policy/interface-migrations/approved-flag-migrations-v1.json
 一条 base-owned、状态正确且前后快照精确匹配的记录，只会从普通兼容报告中移除以下两类预期 finding：
 
 1. legacy flag 的 `flag_became_hidden`（visible → hidden）；
-2. required legacy 被新增的 required canonical 替代时产生的 `required_flag_added`。已有 canonical 的 requiredness 不允许借 rename 改变。
+2. required legacy 被新增的 required canonical 替代时产生的 `required_flag_added`；如果 canonical 在 before 阶段只是 hidden 占位符，则允许它在转为公开拼写时继承 legacy 的 requiredness。已有的 visible canonical 不允许借 rename 改变 requiredness。
 
 以下变化仍按普通兼容规则阻塞，不能被迁移记录掩盖：
 
diff --git a/internal/interfacesnapshot/migrations.go b/internal/interfacesnapshot/migrations.go
index 7bd04bcd..892a7c55 100644
--- a/internal/interfacesnapshot/migrations.go
+++ b/internal/interfacesnapshot/migrations.go
@@ -326,8 +326,9 @@ func (m FlagMigration) validate() error {
 	}
 	// Requiredness belongs to the one logical parameter. The hidden legacy
 	// spelling must not remain independently required, while the canonical
-	// spelling inherits the exact before-state contract. If the canonical flag
-	// already existed, a rename receipt cannot authorize changing it either.
+	// spelling inherits the exact before-state contract. An already-visible
+	// canonical flag cannot change requiredness; an existing hidden canonical
+	// placeholder may inherit it when promoted to the public spelling.
 	if m.Legacy.After.Required {
 		return fmt.Errorf("legacy compatibility alias must not remain independently required after migration")
 	}
@@ -336,7 +337,9 @@ func (m FlagMigration) validate() error {
 			"flag requiredness must be preserved from legacy before to canonical after",
 		)
 	}
-	if m.Canonical.Before.Present && m.Canonical.Before.Required != m.Canonical.After.Required {
+	if m.Canonical.Before.Present &&
+		!m.Canonical.Before.Hidden &&
+		m.Canonical.Before.Required != m.Canonical.After.Required {
 		return fmt.Errorf("canonical flag requiredness must remain unchanged when already present")
 	}
 	if m.Legacy.After.AliasOf != m.Canonical.Name {
@@ -690,6 +693,13 @@ func flagMigrationAuthorizesChange(
 			change.Kind == "required_flag_added" {
 			return true
 		}
+		if migration.Canonical.Before.Present &&
+			migration.Canonical.Before.Hidden &&
+			!migration.Canonical.Before.Required &&
+			migration.Canonical.After.Required &&
+			change.Kind == "flag_became_required" {
+			return true
+		}
 	}
 	return false
 }
diff --git a/internal/interfacesnapshot/migrations_coverage_test.go b/internal/interfacesnapshot/migrations_coverage_test.go
index bdee575f..fa4b239f 100644
--- a/internal/interfacesnapshot/migrations_coverage_test.go
+++ b/internal/interfacesnapshot/migrations_coverage_test.go
@@ -792,6 +792,35 @@ func TestCrossPlatformCoverageCompareAllWithFlagMigrationsInheritedAndOptionalCa
 			t.Fatalf("existing optional canonical migration = (%#v, %v), want compatible", report, err)
 		}
 	})
+
+	t.Run("hidden canonical inherits requiredness when promoted", func(t *testing.T) {
+		pending := coverageManifest(FlagMigrationPending)
+		pending.Migrations[0].Canonical.Before = FlagMigrationState{
+			Present: true,
+			Type:    "string",
+			Hidden:  true,
+			Scope:   "local",
+		}
+		consumed := pending
+		consumed.Migrations = append([]FlagMigration(nil), pending.Migrations...)
+		consumed.Migrations[0].State = FlagMigrationConsumed
+		before := coverageMigrationSnapshot(pending.Migrations[0], false, false)
+		after := coverageMigrationSnapshot(pending.Migrations[0], true, false)
+
+		ordinary := Compare(after, before, "merge-base")
+		if !hasFlagChange(ordinary.Blocking, "flag_became_required", pending.Migrations[0].Command, pending.Migrations[0].Canonical.Name) {
+			t.Fatalf("fixture did not change canonical requiredness: %#v", ordinary.Blocking)
+		}
+		report, err := CompareAllWithFlagMigrations(
+			after,
+			map[string]Snapshot{"merge-base": before, "stable": before},
+			pending,
+			consumed,
+		)
+		if err != nil || !report.Compatible {
+			t.Fatalf("hidden canonical promotion = (%#v, %v), want compatible", report, err)
+		}
+	})
 }
 
 func TestCrossPlatformCoverageOptionalFlagMigrationLifecycleRemainsHostile(t *testing.T) {
diff --git a/internal/interfacesnapshot/migrations_test.go b/internal/interfacesnapshot/migrations_test.go
index a7996dba..f9c406f7 100644
--- a/internal/interfacesnapshot/migrations_test.go
+++ b/internal/interfacesnapshot/migrations_test.go
@@ -5,6 +5,7 @@ package interfacesnapshot
 
 import (
 	"errors"
+	"os"
 	"reflect"
 	"strings"
 	"testing"
@@ -52,6 +53,27 @@ func optionalFlagMigrationManifestJSON() string {
 	)
 }
 
+func hiddenCanonicalFlagMigrationManifestJSON() string {
+	return strings.Replace(
+		validFlagMigrationManifestJSON,
+		`"before": {"present": false}`,
+		`"before": {"present": true, "type": "string", "hidden": true, "scope": "local"}`,
+		1,
+	)
+}
+
+func TestApprovedFlagMigrationManifestRemainsValid(t *testing.T) {
+	manifest, err := os.Open("../../scripts/policy/interface-migrations/approved-flag-migrations-v1.json")
+	if err != nil {
+		t.Fatalf("open approved flag migration manifest: %v", err)
+	}
+	defer manifest.Close()
+
+	if _, err := ReadFlagMigrationManifest(manifest); err != nil {
+		t.Fatalf("approved flag migration manifest is invalid: %v", err)
+	}
+}
+
 func TestCrossPlatformCoverageReadFlagMigrationManifestRejectsUnknownFields(t *testing.T) {
 	_, err := ReadFlagMigrationManifest(strings.NewReader(`{
   "version": 1,
@@ -128,6 +150,9 @@ func TestCrossPlatformCoverageReadFlagMigrationManifestValidatesExactEntries(t *
 	if _, err := ReadFlagMigrationManifest(strings.NewReader(optionalFlagMigrationManifestJSON())); err != nil {
 		t.Fatalf("ReadFlagMigrationManifest(optional rename) error = %v", err)
 	}
+	if _, err := ReadFlagMigrationManifest(strings.NewReader(hiddenCanonicalFlagMigrationManifestJSON())); err != nil {
+		t.Fatalf("ReadFlagMigrationManifest(hidden canonical promotion) error = %v", err)
+	}
 
 	tests := []struct {
 		name    string