fix(billing): retry missing Autumn balance (#450)

src/server/billing/subscription.test.ts

@@ -1,5 +1,9 @@
-import { beforeEach, describe, expect, it, vi } from "vitest";
-import { AUTUMN_PAID_PLAN_FEATURE_ID } from "@/shared/billing";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import {
+  AUTUMN_PAID_PLAN_FEATURE_ID,
+  AUTUMN_SEO_DATA_BALANCE_FEATURE_ID,
+  AUTUMN_SEO_DATA_TOPUP_BALANCE_FEATURE_ID,
+} from "@/shared/billing";
 
 const { checkMock, getOrCreateMock, kvGetMock, kvPutMock } = vi.hoisted(() => ({
   checkMock: vi.fn(),
@@ -32,6 +36,7 @@ vi.mock("@/server/lib/posthog", () => ({
 }));
 
 import {
+  assertUsageCreditsAvailable,
   customerHasPaidPlan,
   getOrCreateOrganizationCustomer,
 } from "./subscription";
@@ -43,6 +48,10 @@ describe("subscription billing", () => {
     kvPutMock.mockResolvedValue(undefined);
   });
 
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
   it("checks the paid plan entitlement", async () => {
     checkMock.mockResolvedValue({ allowed: true });
 
@@ -60,6 +69,45 @@ describe("subscription billing", () => {
     await expect(customerHasPaidPlan("org_123")).resolves.toBe(false);
   });
 
+  it("retries a missing monthly balance once", async () => {
+    vi.useFakeTimers();
+    let monthlyChecks = 0;
+    checkMock.mockImplementation(
+      async ({ featureId }: { featureId: string }) => {
+        if (featureId === AUTUMN_SEO_DATA_TOPUP_BALANCE_FEATURE_ID) {
+          return { balance: null };
+        }
+        if (featureId === AUTUMN_SEO_DATA_BALANCE_FEATURE_ID) {
+          monthlyChecks += 1;
+          return monthlyChecks === 1
+            ? { balance: null }
+            : { balance: { remaining: 250 } };
+        }
+        throw new Error(`Unexpected feature ${featureId}`);
+      },
+    );
+
+    const result = assertUsageCreditsAvailable("org_123");
+    await vi.runAllTimersAsync();
+
+    await expect(result).resolves.toEqual({ monthlyRemaining: 250 });
+    expect(monthlyChecks).toBe(2);
+  });
+
+  it("fails closed when the retry still has no monthly balance", async () => {
+    vi.useFakeTimers();
+    checkMock.mockResolvedValue({ balance: null });
+
+    const result = assertUsageCreditsAvailable("org_123");
+    const assertion = expect(result).rejects.toMatchObject({
+      code: "UPSTREAM_UNAVAILABLE",
+    });
+    await vi.runAllTimersAsync();
+
+    await assertion;
+    expect(checkMock).toHaveBeenCalledTimes(3);
+  });
+
   it("looks up the billing customer by organization id", async () => {
     getOrCreateMock.mockResolvedValue({ id: "cust_123" });
 

src/server/billing/subscription.ts

@@ -96,13 +96,26 @@ async function getUsageCreditsRemaining(customerId: string): Promise<{
     }),
   ]);
 
+  // Autumn sometimes returns a successful response with no monthly balance
+  // for a customer that holds the feature. Retry that read once because the
+  // SDK's retry policy only covers failed HTTP requests.
+  let monthlyBalance = monthlyCheck.balance;
+  if (!monthlyBalance) {
+    await new Promise((resolve) => setTimeout(resolve, 300));
+    const retry = await autumn.check({
+      customerId,
+      featureId: AUTUMN_SEO_DATA_BALANCE_FEATURE_ID,
+    });
+    monthlyBalance = retry.balance;
+  }
+
   // Every hosted org holds the monthly feature (the free plan is the Autumn
   // default, attached at customer creation), so a check with no balance data
   // is a broken read, not an empty wallet. Throwing keeps it out of the
   // credit math — coercing it to 0 once locked a paying customer with ~9k
   // credits out of chat (2026-07-20). The topup balance genuinely doesn't
   // exist until a first top-up, so 0 is the honest reading there.
-  if (!monthlyCheck.balance) {
+  if (!monthlyBalance) {
     throw new AppError(
       "UPSTREAM_UNAVAILABLE",
       `Autumn check returned no ${AUTUMN_SEO_DATA_BALANCE_FEATURE_ID} balance for customer ${customerId}`,
@@ -110,7 +123,7 @@ async function getUsageCreditsRemaining(customerId: string): Promise<{
   }
 
   return {
-    monthlyRemaining: monthlyCheck.balance.remaining,
+    monthlyRemaining: monthlyBalance.remaining,
     topupRemaining: topupCheck.balance?.remaining ?? 0,
   };
 }