diff --git a/app/Services/Billing/AddonPrices.php b/app/Services/Billing/AddonPrices.php
index acabe91..e2aa6db 100644
--- a/app/Services/Billing/AddonPrices.php
+++ b/app/Services/Billing/AddonPrices.php
@@ -318,17 +318,14 @@ final class AddonPrices
             // nothing to correct here beyond letting the first row stand.
             //
             // What keeps two ROWS off one Price id is the `claimed` callback in
-            // ensure(), asked before minting — not this table. Today
-            // `stripe_addon_prices` is unique on (addon_key, reverse_charge,
-            // amount_cents, currency, interval) only; nothing here refuses a
-            // second row for a Price id another row already claims. (That unique
-            // index is `stripe_plan_prices.stripe_price_id`, on the PLAN side —
-            // easy to mistake for a guarantee this table shares, and it does
-            // not.) 2026_07_31_210000_one_row_per_stripe_price adds a matching
-            // index here, as a net under `claimed` rather than instead of it:
-            // two rows sharing one Price is worse than a duplicate, because
-            // archiving one — the ordinary response to a superseded figure —
-            // would then withdraw the very Price the other row is still
+            // ensure(), asked before minting. The unique index on
+            // `stripe_price_id` (`stripe_addon_prices_price_unique`, since
+            // 2026_07_31_210000_one_row_per_stripe_price, matching
+            // `stripe_plan_prices.stripe_price_id` on the plan side) is the net
+            // UNDER that callback, not a substitute for it — two rows sharing one
+            // Price would be worse than the ordinary duplicate this catch
+            // handles: archiving one — the ordinary response to a superseded
+            // figure — would then withdraw the very Price the other row is still
             // selling.
         }
     }
diff --git a/database/migrations/2026_07_31_210000_one_row_per_stripe_price.php b/database/migrations/2026_07_31_210000_one_row_per_stripe_price.php
new file mode 100644
index 0000000..ba3cc10
--- /dev/null
+++ b/database/migrations/2026_07_31_210000_one_row_per_stripe_price.php
@@ -0,0 +1,60 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Schema;
+
+/**
+ * One row per Stripe Price on the module side too.
+ *
+ * `stripe_plan_prices.stripe_price_id` has been unique since
+ * 2026_07_30_110000; the module register was never given the same guard, so two
+ * rows could claim one Price — and archiving the one would have withdrawn the
+ * Price the other was still selling. It is also the net under the adoption step
+ * (App\Services\Billing\AdoptStripePrice): at a VAT rate of nought both
+ * treatments charge the same amount, and the check that refuses an
+ * already-claimed Price is then the only thing keeping them apart.
+ *
+ * Duplicates are DELETED rather than archived. An archived row goes on claiming
+ * the id, and a unique index knows nothing about `archived_at`. Deleting is safe
+ * because the row rebuilds itself: the next ensure() finds the Price at Stripe
+ * through the adoption step and writes the row again. `subscription_addons`
+ * holds the Stripe id as text, not as a foreign key, so no booking loses its
+ * price.
+ */
+return new class extends Migration
+{
+    public function up(): void
+    {
+        // Written with groupBy/having and a delete by id rather than a joined
+        // delete: production is MariaDB and the suite runs on SQLite.
+        $shared = DB::table('stripe_addon_prices')
+            ->select('stripe_price_id')
+            ->groupBy('stripe_price_id')
+            ->havingRaw('count(*) > 1')
+            ->pluck('stripe_price_id');
+
+        foreach ($shared as $priceId) {
+            // The lowest id stays — the row that was written first, which is the
+            // one anything already billing is likeliest to have been reading.
+            $keep = DB::table('stripe_addon_prices')->where('stripe_price_id', $priceId)->min('id');
+
+            DB::table('stripe_addon_prices')
+                ->where('stripe_price_id', $priceId)
+                ->where('id', '!=', $keep)
+                ->delete();
+        }
+
+        Schema::table('stripe_addon_prices', function (Blueprint $table) {
+            $table->unique('stripe_price_id', 'stripe_addon_prices_price_unique');
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::table('stripe_addon_prices', function (Blueprint $table) {
+            $table->dropUnique('stripe_addon_prices_price_unique');
+        });
+    }
+};
diff --git a/docs/handoffs/2026-07-30-real-run-handoff.md b/docs/handoffs/2026-07-30-real-run-handoff.md
index 8f51e21..3364113 100644
--- a/docs/handoffs/2026-07-30-real-run-handoff.md
+++ b/docs/handoffs/2026-07-30-real-run-handoff.md
@@ -172,8 +172,11 @@ Neuer Schritt zwischen `SecureHostFirewall` und `CompleteHostOnboarding`:
 - `VerifyVmTemplate` prüft nur **Existenz**, nicht `template: 1`.
 - `applyFirewall()` setzt **nicht** `firewall=1` an `net0` der VM — ohne das greifen
   die Gastregeln trotz Datacenter-Firewall nicht. Prüfen, ob die Vorlage es mitbringt.
-- `stripe_addon_prices.stripe_price_id` ist **nicht** eindeutig (Plan-Seite schon):
-  zwei Zeilen könnten einen Preis teilen, Archivieren würde den anderen mitentziehen.
+- ~~`stripe_addon_prices.stripe_price_id` ist **nicht** eindeutig (Plan-Seite schon):
+  zwei Zeilen könnten einen Preis teilen, Archivieren würde den anderen mitentziehen.~~
+  **Erledigt** — eindeutig seit `2026_07_31_210000_one_row_per_stripe_price`; zugleich
+  das Netz unter dem Wiedererkennungsschritt, siehe
+  `docs/superpowers/specs/2026-07-30-stripe-price-adoption-design.md`.
 - `clupilot:end-due-services` schließt den **Vertrag** nicht — ein geschenkter Vertrag
   bleibt nach Ende der Instanz für immer `active` und zählt in Umsatz/Dashboard mit.
 - Eine Abbuchung, die **vor** dem Widerruf entstand und **danach** bezahlt wird,
diff --git a/tests/Feature/Billing/StripePriceAdoptionTest.php b/tests/Feature/Billing/StripePriceAdoptionTest.php
index f5c3caa..54336c1 100644
--- a/tests/Feature/Billing/StripePriceAdoptionTest.php
+++ b/tests/Feature/Billing/StripePriceAdoptionTest.php
@@ -12,6 +12,7 @@ use App\Services\Billing\TaxTreatment;
 use App\Services\Stripe\FakeStripeClient;
 use App\Services\Stripe\StripeClient;
 use Illuminate\Contracts\Console\Kernel;
+use Illuminate\Database\UniqueConstraintViolationException;
 use Illuminate\Support\Facades\Log;
 
 /**
@@ -450,3 +451,19 @@ it('does not adopt a package price that only proves the family, not this row', f
         ->and(count($this->stripe->prices))->toBe($before + 1)
         ->and($this->stripe->archived)->not->toContain('price_family_only');
 });
+
+it('lets no two module rows claim one stripe price', function () {
+    $shared = [
+        'addon_key' => 'priority_support', 'net_cents' => 2900, 'currency' => 'EUR',
+        'stripe_product_id' => 'prod_support', 'stripe_price_id' => 'price_shared',
+    ];
+
+    StripeAddonPrice::query()->create([...$shared,
+        'reverse_charge' => false, 'amount_cents' => 3480, 'interval' => 'month']);
+
+    // Two rows on one Price is what Block D warned about: archiving the one
+    // would withdraw the Price the other is still selling.
+    expect(fn () => StripeAddonPrice::query()->create([...$shared,
+        'reverse_charge' => true, 'amount_cents' => 2900, 'interval' => 'month']))
+        ->toThrow(UniqueConstraintViolationException::class);
+});