diff --git a/apps/platform/tests/Feature/Baselines/BaselineCompareExplanationFallbackTest.php b/apps/platform/tests/Feature/Baselines/BaselineCompareExplanationFallbackTest.php
index 173ce656..57c17a9e 100644
--- a/apps/platform/tests/Feature/Baselines/BaselineCompareExplanationFallbackTest.php
+++ b/apps/platform/tests/Feature/Baselines/BaselineCompareExplanationFallbackTest.php
@@ -2,14 +2,12 @@
 
 declare(strict_types=1);
 
-use App\Filament\Pages\BaselineCompareLanding;
 use App\Models\BaselineProfile;
 use App\Models\BaselineSnapshot;
 use App\Models\BaselineTenantAssignment;
 use App\Support\Baselines\BaselineCompareStats;
 use App\Support\Ui\OperatorExplanation\ExplanationFamily;
 use Filament\Facades\Filament;
-use Livewire\Livewire;
 
 it('shows an unavailable explanation before any baseline compare result exists', function (): void {
     [$user, $tenant] = createUserWithTenant(role: 'owner');
@@ -43,8 +41,7 @@
         ->and($explanation->family)->toBe(ExplanationFamily::Unavailable)
         ->and($explanation->nextActionText)->toBe('Run the baseline compare to generate a result');
 
-    Livewire::actingAs($user)
-        ->test(BaselineCompareLanding::class)
+    baselineCompareLandingLivewire($tenant, user: $user)
         ->assertSee($summary->headline)
         ->assertSee($summary->nextActionLabel())
         ->assertSee($explanation->coverageStatement ?? '');
diff --git a/apps/platform/tests/Feature/Filament/BaselineActionAuthorizationTest.php b/apps/platform/tests/Feature/Filament/BaselineActionAuthorizationTest.php
index 00d1f92c..cb4108db 100644
--- a/apps/platform/tests/Feature/Filament/BaselineActionAuthorizationTest.php
+++ b/apps/platform/tests/Feature/Filament/BaselineActionAuthorizationTest.php
@@ -2,7 +2,6 @@
 
 declare(strict_types=1);
 
-use App\Filament\Pages\BaselineCompareLanding;
 use App\Filament\Resources\BaselineProfileResource\Pages\ViewBaselineProfile;
 use App\Support\Workspaces\WorkspaceContext;
 use Filament\Facades\Filament;
@@ -37,12 +36,10 @@
     $tenant->makeCurrent();
     Filament::setTenant($tenant, true);
 
-    Livewire::actingAs($readonlyUser)
-        ->test(BaselineCompareLanding::class)
+    baselineCompareLandingLivewire($tenant, user: $readonlyUser)
         ->assertActionDisabled('compareNow');
 
-    Livewire::actingAs($ownerUser)
-        ->test(BaselineCompareLanding::class)
+    baselineCompareLandingLivewire($tenant, user: $ownerUser)
         ->assertActionEnabled('compareNow');
 });
 
diff --git a/apps/platform/tests/Feature/Filament/BaselineCompareExplanationSurfaceTest.php b/apps/platform/tests/Feature/Filament/BaselineCompareExplanationSurfaceTest.php
index 17b720bf..963d9141 100644
--- a/apps/platform/tests/Feature/Filament/BaselineCompareExplanationSurfaceTest.php
+++ b/apps/platform/tests/Feature/Filament/BaselineCompareExplanationSurfaceTest.php
@@ -2,7 +2,6 @@
 
 declare(strict_types=1);
 
-use App\Filament\Pages\BaselineCompareLanding;
 use App\Models\BaselineProfile;
 use App\Models\BaselineSnapshot;
 use App\Models\BaselineTenantAssignment;
@@ -12,7 +11,6 @@
 use App\Support\ReasonTranslation\ReasonPresenter;
 use App\Support\Ui\OperatorExplanation\ExplanationFamily;
 use Filament\Facades\Filament;
-use Livewire\Livewire;
 
 it('renders suppressed baseline-compare results as explanation-first output instead of an implicit all-clear', function (): void {
     [$user, $tenant] = createUserWithTenant(role: 'owner');
@@ -82,8 +80,7 @@
     expect($explanation->family)->toBe(ExplanationFamily::SuppressedOutput);
     expect($reasonSemantics)->not->toBeNull();
 
-    Livewire::actingAs($user)
-        ->test(BaselineCompareLanding::class)
+    baselineCompareLandingLivewire($tenant, user: $user)
         ->assertSee($summary->headline)
         ->assertSee($explanation->trustworthinessLabel())
         ->assertSee($summary->nextActionLabel())
diff --git a/apps/platform/tests/Feature/Filament/BaselineCompareSummaryConsistencyTest.php b/apps/platform/tests/Feature/Filament/BaselineCompareSummaryConsistencyTest.php
index 97af52c3..61bd22b1 100644
--- a/apps/platform/tests/Feature/Filament/BaselineCompareSummaryConsistencyTest.php
+++ b/apps/platform/tests/Feature/Filament/BaselineCompareSummaryConsistencyTest.php
@@ -2,7 +2,6 @@
 
 declare(strict_types=1);
 
-use App\Filament\Pages\BaselineCompareLanding;
 use App\Filament\Widgets\Dashboard\BaselineCompareNow;
 use App\Filament\Widgets\ManagedEnvironment\BaselineCompareCoverageBanner;
 use App\Models\BaselineProfile;
@@ -91,7 +90,7 @@ function createBaselineCompareSummaryConsistencyTenant(): array
         ->assertSee('The last compare finished, but normal result output was suppressed.')
         ->assertDontSee('Aligned');
 
-    Livewire::test(BaselineCompareLanding::class)
+    baselineCompareLandingLivewire($tenant)
         ->assertSee('Needs review')
         ->assertSee('The last compare finished, but normal result output was suppressed.')
         ->assertSee('Limited confidence')
@@ -141,7 +140,7 @@ function createBaselineCompareSummaryConsistencyTenant(): array
         ->assertSee('overdue finding')
         ->assertSee('Open findings');
 
-    Livewire::test(BaselineCompareLanding::class)
+    baselineCompareLandingLivewire($tenant)
         ->assertSee('Action required')
         ->assertSee('overdue finding')
         ->assertSee('Open findings');
@@ -174,7 +173,7 @@ function createBaselineCompareSummaryConsistencyTenant(): array
         ->assertSee('Baseline compare is in progress.')
         ->assertSee('Open operation');
 
-    Livewire::test(BaselineCompareLanding::class)
+    baselineCompareLandingLivewire($tenant)
         ->assertSee('In progress')
         ->assertSee('Baseline compare is in progress.')
         ->assertSee('Open operation');
diff --git a/apps/platform/tests/Feature/Filament/BaselineGapSurfacesDbOnlyRenderTest.php b/apps/platform/tests/Feature/Filament/BaselineGapSurfacesDbOnlyRenderTest.php
index 572c33fd..6966ce62 100644
--- a/apps/platform/tests/Feature/Filament/BaselineGapSurfacesDbOnlyRenderTest.php
+++ b/apps/platform/tests/Feature/Filament/BaselineGapSurfacesDbOnlyRenderTest.php
@@ -123,7 +123,7 @@ function structuredGapSurfaceContext(): array
         'completed_at' => now(),
     ]);
 
-    Livewire::test(BaselineCompareLanding::class)
+    baselineCompareLandingLivewire($tenant)
         ->assertSee('Evidence gap details')
         ->assertSee('Subject class')
         ->assertSee('Outcome')
diff --git a/apps/platform/tests/Feature/Guards/ActionSurfaceContractTest.php b/apps/platform/tests/Feature/Guards/ActionSurfaceContractTest.php
index 00dd27a3..454db154 100644
--- a/apps/platform/tests/Feature/Guards/ActionSurfaceContractTest.php
+++ b/apps/platform/tests/Feature/Guards/ActionSurfaceContractTest.php
@@ -2452,8 +2452,7 @@ function actionSurfaceSystemPanelContext(array $capabilities): PlatformUser
         'baseline_profile_id' => (int) $profile->getKey(),
     ]);
 
-    Livewire::actingAs($approver)
-        ->test(BaselineCompareLanding::class)
+    baselineCompareLandingLivewire($tenant, user: $approver)
         ->assertActionExists('compareNow', function (Action $action): bool {
             return $action->isConfirmationRequired()
                 && $action->getModalDescription() === 'This will refresh content evidence on demand (redacted) before comparing the current tenant inventory against the assigned baseline snapshot.';
diff --git a/apps/platform/tests/Pest.php b/apps/platform/tests/Pest.php
index 13b24f5c..f7d67cd7 100644
--- a/apps/platform/tests/Pest.php
+++ b/apps/platform/tests/Pest.php
@@ -818,12 +818,20 @@ function createUserWithTenant(
     return [$user, $tenant];
 }
 
-function baselineCompareLandingLivewire(ManagedEnvironment $tenant, array $queryParams = []): mixed
+function baselineCompareLandingLivewire(
+    ManagedEnvironment $tenant,
+    array $queryParams = [],
+    ?\Illuminate\Contracts\Auth\Authenticatable $user = null,
+): mixed
 {
     $manager = \Livewire\Livewire::withHeaders([
         'Referer' => \App\Support\ManagedEnvironmentLinks::baselineCompareUrl($tenant),
     ]);
 
+    if ($user instanceof \Illuminate\Contracts\Auth\Authenticatable) {
+        $manager = $manager->actingAs($user);
+    }
+
     if ($queryParams !== []) {
         $manager = $manager->withQueryParams($queryParams);
     }
diff --git a/specs/319-environment-owned-surface-routing-shell-context-contract/tasks.md b/specs/319-environment-owned-surface-routing-shell-context-contract/tasks.md
index 69cfc9aa..d31c41c3 100644
--- a/specs/319-environment-owned-surface-routing-shell-context-contract/tasks.md
+++ b/specs/319-environment-owned-surface-routing-shell-context-contract/tasks.md
@@ -172,3 +172,22 @@ ## Implementation Evidence
   - scoped Pint on touched PHP files.
   - `git diff --check`
 - Broader `./vendor/bin/sail artisan test --filter=DecisionRegister` surfaced an existing unrelated failure in `FindingExceptionDecisionRegisterNavigationTest` where the expected back URL still includes `managed_environment_id`; no Spec 319 files or Decision Register code were changed for that.
+
+## Reopened Validation Note
+
+Spec 322's broader no-drift regression split exposed five Baseline Compare tests that still mounted `BaselineCompareLanding` without route-owned Environment context. That direct Livewire mount contradicted the Spec 319 hard cutover even though the runtime route contract was already canonical.
+
+Fix applied on the 319 session branch:
+
+- Extended the existing `baselineCompareLandingLivewire()` test helper so tests can pass an explicit acting user while preserving the canonical Baseline Compare referer and `environment` mount parameter.
+- Updated Baseline Compare explanation, summary-consistency, authorization, gap-surface, and action-surface tests to mount through explicit Environment ownership instead of remembered/implicit panel tenant state.
+- Confirmed no direct `Livewire::test(BaselineCompareLanding::class)` Feature/Unit mount remains.
+
+Validation after reopening:
+
+- `./vendor/bin/sail artisan test tests/Feature/Baselines/BaselineCompareExplanationFallbackTest.php tests/Feature/Filament/BaselineCompareExplanationSurfaceTest.php tests/Feature/Filament/BaselineCompareSummaryConsistencyTest.php --compact`
+  - Result: 5 passed, 42 assertions.
+- `./vendor/bin/sail artisan test tests/Feature/Filament/BaselineActionAuthorizationTest.php tests/Feature/Filament/BaselineGapSurfacesDbOnlyRenderTest.php tests/Feature/Guards/ActionSurfaceContractTest.php --filter='baseline|compareNow|full content' --compact`
+  - Result: 20 passed, 199 assertions.
+- `./vendor/bin/sail artisan test tests/Unit tests/Feature --filter='WorkspaceHub|EnvironmentFilter|ClearFilter|LegacyTenant|BaselineCompare|WorkspaceOwnedAnalysis|AlertsAudit' --compact`
+  - Result: 233 passed, 1826 assertions.