diff --git a/services/platform-service/src/modules/marketplace/creator-program.test.ts b/services/platform-service/src/modules/marketplace/creator-program.test.ts
index 1ad493fe..792002ee 100644
--- a/services/platform-service/src/modules/marketplace/creator-program.test.ts
+++ b/services/platform-service/src/modules/marketplace/creator-program.test.ts
@@ -129,6 +129,20 @@ describe('buildAgentPack', () => {
     expect(pack.productId).toBe('jarvisjr');
   });
 
+  it('throws when agentListingIds and individualPrices length mismatch', () => {
+    expect(() =>
+      buildAgentPack({
+        creatorId: 'c1',
+        title: 'Bad Pack',
+        description: 'Mismatched arrays test',
+        category: 'career',
+        agentListingIds: ['l1', 'l2', 'l3'],
+        individualPrices: [4.99, 4.99],
+        discountPercent: 20,
+      })
+    ).toThrow('agentListingIds length (3) must match individualPrices length (2)');
+  });
+
   it('generates unique id', () => {
     const a = buildAgentPack({
       creatorId: 'c1',
diff --git a/services/platform-service/src/modules/marketplace/creator-program.ts b/services/platform-service/src/modules/marketplace/creator-program.ts
index 435e5c97..5739250f 100644
--- a/services/platform-service/src/modules/marketplace/creator-program.ts
+++ b/services/platform-service/src/modules/marketplace/creator-program.ts
@@ -157,6 +157,11 @@ export function buildAgentPack(input: {
   individualPrices: number[];
   discountPercent: number;
 }): AgentPack {
+  if (input.agentListingIds.length !== input.individualPrices.length) {
+    throw new Error(
+      `agentListingIds length (${input.agentListingIds.length}) must match individualPrices length (${input.individualPrices.length})`
+    );
+  }
   const individualTotal = input.individualPrices.reduce((a, b) => a + b, 0);
   const discounted = individualTotal * (1 - input.discountPercent / 100);
   const now = new Date().toISOString();