fix(rotation): persist cooldown when account has no resolvable accountId

lib/runtime-rotation-proxy.ts

@@ -1063,6 +1063,12 @@ async function handleRequestInner(
 					DEFAULT_AUTH_FAILURE_COOLDOWN_MS,
 					"auth-failure",
 				);
+				// Persist the cooldown like every other cooldown branch in this loop
+				// (network-error, 429, server-error, 401). `coolingDownUntil`/
+				// `cooldownReason` are serialized in the V3 snapshot, so without this
+				// a restart inside the cooldown window loses it and immediately
+				// re-selects the still-broken account.
+				accountManager.saveToDiskDebounced();
 				exhaustionReason = "auth-failure";
 				transientAttempts += 1;
 				transientExhaustionReason = "auth-failure";

test/runtime-rotation-proxy.test.ts

@@ -1662,6 +1662,47 @@ describe("runtime rotation proxy", () => {
 		expect(saveToDiskDebouncedSpy).toHaveBeenCalled();
 	});
 
+	it("persists the cooldown when an account has no resolvable accountId", async () => {
+		const now = Date.now();
+		// Account with no stored accountId and a non-JWT access token, so
+		// resolveAccountId returns null and the missing-accountId cooldown branch
+		// fires. The cooldown must be persisted like every other cooldown branch
+		// so a restart inside the window honors it (regression: this branch used
+		// to mutate cooldown state without scheduling a disk write).
+		const storage: AccountStorageV3 = {
+			version: 3,
+			activeIndex: 0,
+			activeIndexByFamily: { codex: 0 },
+			accounts: [
+				{
+					email: "no-id@example.com",
+					refreshToken: "refresh-1",
+					accessToken: "plain-access-not-a-jwt",
+					expiresAt: now + 3_600_000,
+					addedAt: now - 60_000,
+					lastUsed: now - 60_000,
+					enabled: true,
+				},
+			],
+		};
+		const accountManager = new AccountManager(undefined, storage);
+		expect(accountManager.getAccountByIndex(0)?.accountId).toBeUndefined();
+		const saveToDiskDebouncedSpy = vi.spyOn(accountManager, "saveToDiskDebounced");
+		const { calls, fetchImpl } = createRecordingFetch(() => textEventStream());
+		const proxy = await startProxy({ accountManager, fetchImpl });
+
+		const response = await postResponses(proxy, { model: "gpt-5-codex" });
+		await response.text();
+
+		// No upstream request is issued — the account is cooled down before send,
+		// exhausting the single-account pool.
+		expect(response.status).toBe(HTTP_STATUS.SERVICE_UNAVAILABLE);
+		expect(calls).toHaveLength(0);
+		expect(accountManager.getAccountByIndex(0)?.cooldownReason).toBe("auth-failure");
+		expect(accountManager.getAccountByIndex(0)?.coolingDownUntil).toBeGreaterThan(now);
+		expect(saveToDiskDebouncedSpy).toHaveBeenCalled();
+	});
+
 	it("deduplicates concurrent expired-token refresh and persistence", async () => {
 		const now = Date.now();
 		const storage = createStorage(now, 1);