diff --git a/app/Services/Secrets/SecretVault.php b/app/Services/Secrets/SecretVault.php
index e6b5590..1743a7f 100644
--- a/app/Services/Secrets/SecretVault.php
+++ b/app/Services/Secrets/SecretVault.php
@@ -4,6 +4,7 @@ namespace App\Services\Secrets;
 
 use App\Models\Operator;
 use App\Services\Stripe\StripeCheck;
+use App\Support\OperatingMode;
 use Illuminate\Contracts\Encryption\DecryptException;
 use Illuminate\Support\Facades\DB;
 use Illuminate\Support\Facades\Log;
@@ -112,6 +113,10 @@ final class SecretVault
     /**
      * The stored value, or the configured one when nothing is stored.
      *
+     * Signature unchanged from before the vault grew a test/live split — the
+     * three callers (HttpStripeClient, StripeCheck, SshTraefikWriter) have no
+     * business knowing which mode is active; that is resolved in here.
+     *
      * Falls back only when there is genuinely no row — never on a decryption
      * failure. Falling back then would quietly resume using an old key from the
      * environment while the console shows the new one.
@@ -119,9 +124,24 @@ final class SecretVault
     public function get(string $key): ?string
     {
         $this->assertKnown($key);
-        $row = $this->row($key);
+
+        $mode = OperatingMode::current();
+        $row = $this->row($key, $mode);
+
+        // Fall back to the live slot when the active mode's slot is empty.
+        // ONLY from test to live, never the other way: using a test credential
+        // in live operation because the real one is missing is the dangerous
+        // direction, and must stay an explicit, visible gap instead.
+        if ($row === null && $mode->isTest() && ! $this->isStrict($key)) {
+            $row = $this->row($key, OperatingMode::Live);
+        }
 
         if ($row === null) {
+            // Strict entries never see the environment: see isStrict() below.
+            if ($this->isStrict($key)) {
+                return null;
+            }
+
             $configured = config(self::REGISTRY[$key]['config']);
 
             return $configured === null ? null : (string) $configured;
@@ -137,28 +157,28 @@ final class SecretVault
     }
 
     /** Where the value in force comes from: stored, environment, or nowhere. */
-    public function source(string $key): string
+    public function source(string $key, ?OperatingMode $mode = null): string
     {
         $this->assertKnown($key);
 
         return match (true) {
-            $this->row($key) !== null => 'stored',
+            $this->row($key, $mode) !== null => 'stored',
             filled(config(self::REGISTRY[$key]['config'])) => 'environment',
             default => 'none',
         };
     }
 
-    public function outline(string $key): ?string
+    public function outline(string $key, ?OperatingMode $mode = null): ?string
     {
-        return $this->row($key)?->outline;
+        return $this->row($key, $mode)?->outline;
     }
 
-    public function updatedAt(string $key): ?string
+    public function updatedAt(string $key, ?OperatingMode $mode = null): ?string
     {
-        return $this->row($key)?->updated_at;
+        return $this->row($key, $mode)?->updated_at;
     }
 
-    public function put(string $key, string $value, Operator $by): void
+    public function put(string $key, string $value, Operator $by, ?OperatingMode $mode = null): void
     {
         $this->assertKnown($key);
 
@@ -176,18 +196,18 @@ final class SecretVault
         // created_at only on the first write: rotating a key must not rewrite
         // when it was first set, which is the one piece of audit metadata that
         // answers "how long has this been here?".
-        if ($this->row($key) === null) {
+        if ($this->row($key, $mode) === null) {
             $attributes['created_at'] = now();
         }
 
-        DB::table('app_secrets')->updateOrInsert(['key' => $key], $attributes);
+        DB::table('app_secrets')->updateOrInsert(['key' => $this->rowKey($key, $mode)], $attributes);
     }
 
     /** Remove the stored value, falling back to whatever the environment says. */
-    public function forget(string $key): void
+    public function forget(string $key, ?OperatingMode $mode = null): void
     {
         $this->assertKnown($key);
-        DB::table('app_secrets')->where('key', $key)->delete();
+        DB::table('app_secrets')->where('key', $this->rowKey($key, $mode))->delete();
     }
 
     /** Is storing credentials possible at all on this installation? */
@@ -196,9 +216,21 @@ final class SecretVault
         return app(SecretCipher::class)->isUsable();
     }
 
-    private function row(string $key): ?object
+    /** The storage key for one entry: an entry has two slots, test and live. */
+    private function rowKey(string $key, ?OperatingMode $mode = null): string
     {
-        return DB::table('app_secrets')->where('key', $key)->first();
+        return $key.':'.($mode ?? OperatingMode::current())->value;
+    }
+
+    private function row(string $key, ?OperatingMode $mode = null): ?object
+    {
+        return DB::table('app_secrets')->where('key', $this->rowKey($key, $mode))->first();
+    }
+
+    /** Does this entry carry the strict trait? Populated in task 3. */
+    private function isStrict(string $key): bool
+    {
+        return (bool) (self::REGISTRY[$key]['strict'] ?? false);
     }
 
     private function assertKnown(string $key): void
diff --git a/tests/Feature/Admin/SecretVaultTest.php b/tests/Feature/Admin/SecretVaultTest.php
index 079d010..c93ef25 100644
--- a/tests/Feature/Admin/SecretVaultTest.php
+++ b/tests/Feature/Admin/SecretVaultTest.php
@@ -5,6 +5,7 @@ use App\Services\Dns\HttpHetznerDnsClient;
 use App\Services\Monitoring\HttpMonitoringClient;
 use App\Services\Secrets\SecretVault;
 use App\Services\Stripe\HttpStripeClient;
+use App\Support\OperatingMode;
 use Illuminate\Support\Facades\DB;
 use Illuminate\Support\Facades\Http;
 
@@ -17,6 +18,12 @@ use Illuminate\Support\Facades\Http;
 beforeEach(function () {
     config()->set('admin_access.secrets_key', 'base64:'.base64_encode(random_bytes(32)));
     config()->set('services.stripe.secret', 'sk_env_fallback');
+
+    // None of these tests are about the test/live split (that is
+    // SecretVaultModeTest); they call put()/get() without a $mode and must
+    // therefore land on a known slot regardless of what an earlier test file
+    // left in the array cache that Settings and OperatingMode share.
+    OperatingMode::set(OperatingMode::Live);
 });
 
 it('prefers a stored key over the environment, and says which is in force', function () {
@@ -38,7 +45,9 @@ it('prefers a stored key over the environment, and says which is in force', func
 it('stores the value encrypted, and never in the clear', function () {
     app(SecretVault::class)->put('stripe.secret', 'sk_live_verysecret', Operator::factory()->create());
 
-    $stored = DB::table('app_secrets')->where('key', 'stripe.secret')->value('value');
+    // The row key carries a mode suffix (SecretVaultModeTest) — the active
+    // mode here is pinned to live above.
+    $stored = DB::table('app_secrets')->where('key', 'stripe.secret:live')->value('value');
 
     expect($stored)->not->toContain('sk_live_verysecret');
 });
@@ -161,10 +170,10 @@ it('keeps the original creation date when a key is rotated', function () {
     $operator = Operator::factory()->create();
     app(SecretVault::class)->put('stripe.secret', 'sk_first', $operator);
 
-    $created = DB::table('app_secrets')->where('key', 'stripe.secret')->value('created_at');
+    $created = DB::table('app_secrets')->where('key', 'stripe.secret:live')->value('created_at');
 
     $this->travel(2)->days();
     app(SecretVault::class)->put('stripe.secret', 'sk_second', $operator);
 
-    expect(DB::table('app_secrets')->where('key', 'stripe.secret')->value('created_at'))->toBe($created);
+    expect(DB::table('app_secrets')->where('key', 'stripe.secret:live')->value('created_at'))->toBe($created);
 });
diff --git a/tests/Feature/SecretVaultModeTest.php b/tests/Feature/SecretVaultModeTest.php
new file mode 100644
index 0000000..d54a662
--- /dev/null
+++ b/tests/Feature/SecretVaultModeTest.php
@@ -0,0 +1,75 @@
+<?php
+
+use App\Models\Operator;
+use App\Services\Secrets\SecretVault;
+use App\Support\OperatingMode;
+
+/**
+ * Zwei Plätze je Zugangsdatum, und eine Rückfallregel, die für vier von fünf
+ * Einträgen richtig ist: es gibt bei Hetzner, Uptime Kuma und SSH nur ein
+ * Konto, und zwei Felder mit zwingend gleichem Inhalt wären eine Attrappe.
+ */
+beforeEach(function () {
+    $this->by = Operator::factory()->create();
+    $this->vault = app(SecretVault::class);
+
+    // HETZNER_DNS_TOKEN is real in this operator's .env and, unlike
+    // STRIPE_WEBHOOK_SECRET, not blanked in phpunit.xml — left alone, the
+    // fallback-to-environment tests below would silently pass or fail
+    // depending on whose machine runs them instead of on the code.
+    config()->set('provisioning.dns.token', null);
+});
+
+it('reads the slot of the active mode', function () {
+    $this->vault->put('dns.token', 'live-token', $this->by, OperatingMode::Live);
+    $this->vault->put('dns.token', 'test-token', $this->by, OperatingMode::Test);
+
+    OperatingMode::set(OperatingMode::Test);
+    expect($this->vault->get('dns.token'))->toBe('test-token');
+
+    OperatingMode::set(OperatingMode::Live);
+    expect($this->vault->get('dns.token'))->toBe('live-token');
+});
+
+it('falls back to the live slot when the test slot is empty', function () {
+    // Die Regel des Inhabers: wo es keinen Testzugang gibt, wird der echte
+    // benutzt, damit der Testbetrieb überhaupt arbeiten kann.
+    $this->vault->put('dns.token', 'live-token', $this->by, OperatingMode::Live);
+    OperatingMode::set(OperatingMode::Test);
+
+    expect($this->vault->get('dns.token'))->toBe('live-token');
+});
+
+it('does not fall back from live to test', function () {
+    // Die andere Richtung wäre absurd: im Livebetrieb einen Testzugang zu
+    // benutzen, weil der echte fehlt.
+    $this->vault->put('dns.token', 'test-token', $this->by, OperatingMode::Test);
+    OperatingMode::set(OperatingMode::Live);
+
+    expect($this->vault->get('dns.token'))->toBeNull();
+});
+
+it('still falls back to the environment when neither slot is filled', function () {
+    // Der Weg für eine Installation, in der noch gar nichts gespeichert ist.
+    // Einwertig und modusfrei — den Anfangszustand gibt es nur einmal.
+    config()->set('provisioning.dns.token', 'from-env');
+
+    expect($this->vault->get('dns.token'))->toBe('from-env');
+});
+
+it('reports the source per slot', function () {
+    $this->vault->put('dns.token', 'live-token', $this->by, OperatingMode::Live);
+
+    expect($this->vault->source('dns.token', OperatingMode::Live))->toBe('stored');
+    expect($this->vault->source('dns.token', OperatingMode::Test))->toBe('none');
+});
+
+it('forgets one slot without touching the other', function () {
+    $this->vault->put('dns.token', 'live-token', $this->by, OperatingMode::Live);
+    $this->vault->put('dns.token', 'test-token', $this->by, OperatingMode::Test);
+
+    $this->vault->forget('dns.token', OperatingMode::Test);
+
+    expect($this->vault->source('dns.token', OperatingMode::Test))->toBe('none');
+    expect($this->vault->source('dns.token', OperatingMode::Live))->toBe('stored');
+});