fix(usage): fail closed on budget enforcement for unpriced auto alias (#12341) (#13257)

Merged as part of the 39-PR owner batch of 2026-09-11, validated as a unit.

Boarded into one consolidated worktree cut from `release/v3.8.51` with the other 38 — zero conflicts between them.

- ESLint over every changed file: no errors (the only finding was one suppression entry the batch emptied, pruned on #13243)
- `typecheck:core` clean; `check:dashboard-typecheck` OK (206 pre-existing, within baseline); `check:changelog-integrity` OK
- complexity 2821 / baseline 3218 and cognitive-complexity 1272 / baseline 1437 — both under baseline
- 256 assertions green: 246 under node:test and 10 under vitest, which is where `tests/unit/**/*.test.tsx` actually runs
- `check-file-size`: `chatCore.ts` rebaselined 6144 → 6146 for #13278 and #13276, annotated and landed on #13243

⚠️ base-red inherited: #12732 — the provider count (356 in the docs vs the 358 the modules define) and `open-sse/utils/stream.ts` at 3115 > frozen 3098 both reproduce on the pure tip with zero contribution from this batch.

changelog.d/fixes/12341-budget-alias-auto.md

@@ -0,0 +1 @@
+- fix(usage): fail closed on API-key budget enforcement when a provider's `auto` routing alias has no pricing row, instead of silently counting it as $0 (#12341)

src/lib/usage/apiKeyUsageLimits.ts

@@ -1,7 +1,7 @@
 import { getDbInstance } from "@/lib/db/core";
 import type { ProviderLimitsCacheEntry } from "@/lib/db/providerLimits";
 import { getProviderQuotaWindowStartIso } from "@/lib/db/quotaResetEvents";
-import { calculateCost } from "./costCalculator";
+import { calculateCostDetailed } from "./costCalculator";
 import { buildErrorBody, sanitizeErrorMessage } from "@omniroute/open-sse/utils/error.ts";
 
 const FORTALEZA_UTC_OFFSET_MS = 3 * 60 * 60 * 1000;
@@ -29,6 +29,15 @@ export interface ApiKeyUsageLimitStatus {
   weeklyResetAtIso: string | null;
   dailyExceeded: boolean;
   weeklyExceeded: boolean;
+  /**
+   * True when at least one usage_history row in the daily/weekly window could not
+   * be priced at all (no pricing row for the provider+model — e.g. a routing
+   * alias such as `auto`, #12341). Enforcement fails closed on this: an unpriced
+   * row forces `*Exceeded = true` rather than silently contributing $0 to spend,
+   * since a real cost may be hiding behind the alias.
+   */
+  dailyHasUnpricedUsage?: boolean;
+  weeklyHasUnpricedUsage?: boolean;
 }
 
 export interface ApiKeyUsageLimitDeps {
@@ -373,8 +382,14 @@ async function getProviderWeeklyWindow(
   };
 }
 
-async function getApiKeyUsdSpendSince(apiKeyId: string, sinceIso: string): Promise<number> {
-  if (!apiKeyId) return 0;
+interface ApiKeyUsdSpend {
+  totalUsd: number;
+  /** True when at least one (provider, model) group had no pricing row at all (#12341). */
+  hasUnpricedUsage: boolean;
+}
+
+async function getApiKeyUsdSpendSince(apiKeyId: string, sinceIso: string): Promise<ApiKeyUsdSpend> {
+  if (!apiKeyId) return { totalUsd: 0, hasUnpricedUsage: false };
   const db = getDbInstance();
   const rows = db
     .prepare(
@@ -398,12 +413,13 @@ async function getApiKeyUsdSpendSince(apiKeyId: string, sinceIso: string): Promi
     .all({ apiKeyId, sinceIso }) as UsageCostRow[];
 
   let total = 0;
+  let hasUnpricedUsage = false;
   for (const row of rows) {
     const provider = typeof row.provider === "string" ? row.provider : "";
     const model = typeof row.model === "string" ? row.model : "";
     if (!provider || !model) continue;
 
-    total += await calculateCost(
+    const { costUsd, priced } = await calculateCostDetailed(
       provider,
       model,
       {
@@ -419,9 +435,17 @@ async function getApiKeyUsdSpendSince(apiKeyId: string, sinceIso: string): Promi
         serviceTier: row.serviceTier || "standard",
       }
     );
+    if (!priced) {
+      hasUnpricedUsage = true;
+      console.warn(
+        `[apiKeyUsageLimits] no pricing found for ${provider}/${model} — usage counted as $0 ` +
+          "and enforcement is failing closed for this window (#12341)"
+      );
+    }
+    total += costUsd;
   }
 
-  return roundUsd(total);
+  return { totalUsd: roundUsd(total), hasUnpricedUsage };
 }
 
 export async function getApiKeyUsageLimitStatus(
@@ -443,10 +467,27 @@ export async function getApiKeyUsageLimitStatus(
   const weeklyLimitUsd = normalizeLimitUsd(metadata.weeklyUsageLimitUsd);
   const enabled = metadata.usageLimitEnabled === true;
 
-  const [dailySpentUsd, weeklySpentUsd] = await Promise.all([
+  const [dailySpend, weeklySpend] = await Promise.all([
     getApiKeyUsdSpendSince(metadata.id, dailyWindowStartIso),
     getApiKeyUsdSpendSince(metadata.id, weeklyWindowStartIso),
   ]);
+  const dailySpentUsd = dailySpend.totalUsd;
+  const weeklySpentUsd = weeklySpend.totalUsd;
+
+  // Fail closed (#12341): a window with a configured limit that also contains
+  // usage which could not be priced at all (e.g. a provider's `auto` routing
+  // alias with no catalog price) must not let that usage silently pass the cap
+  // as an invisible $0 — treat the limit as exceeded rather than trust an
+  // undercounted spend total. A window with no configured limit was never
+  // enforced, so unpriced usage there is only logged, not blocking.
+  const dailyExceeded =
+    enabled &&
+    dailyLimitUsd !== null &&
+    (dailySpentUsd >= dailyLimitUsd || dailySpend.hasUnpricedUsage);
+  const weeklyExceeded =
+    enabled &&
+    weeklyLimitUsd !== null &&
+    (weeklySpentUsd >= weeklyLimitUsd || weeklySpend.hasUnpricedUsage);
 
   return {
     enabled,
@@ -458,8 +499,10 @@ export async function getApiKeyUsageLimitStatus(
     dailyResetAtIso,
     weeklyWindowStartIso,
     weeklyResetAtIso,
-    dailyExceeded: enabled && dailyLimitUsd !== null && dailySpentUsd >= dailyLimitUsd,
-    weeklyExceeded: enabled && weeklyLimitUsd !== null && weeklySpentUsd >= weeklyLimitUsd,
+    dailyExceeded,
+    weeklyExceeded,
+    dailyHasUnpricedUsage: dailySpend.hasUnpricedUsage,
+    weeklyHasUnpricedUsage: weeklySpend.hasUnpricedUsage,
   };
 }
 

src/lib/usage/costCalculator.ts

@@ -175,18 +175,31 @@ export function computeCostFromPricing(
   return cost * getCodexFastCostMultiplier(options.provider, options.model, options.serviceTier);
 }
 
-export async function calculateCost(
+/**
+ * Result of a cost calculation that also reports whether the number is backed by
+ * a real pricing row. Budget-enforcement callers (#12341) must be able to tell
+ * "$0, priced" (a genuinely free/flat-rate model) apart from "$0, unpriced" (no
+ * pricing row was ever found — e.g. a routing alias like `auto`) so they can fail
+ * closed on the latter instead of letting it silently pass a hard budget cap.
+ */
+export interface CostCalculationResult {
+  costUsd: number;
+  /** false when no pricing row (direct, normalized, or codex-effortless) was found. */
+  priced: boolean;
+}
+
+export async function calculateCostDetailed(
   provider: string,
   model: string,
   tokens: Record<string, number | undefined> | null | undefined,
   options: CostCalculationOptions = {}
-): Promise<number> {
-  if (!tokens || !provider || !model) return 0;
+): Promise<CostCalculationResult> {
+  if (!tokens || !provider || !model) return { costUsd: 0, priced: true };
 
   // Short-circuit before any pricing DB lookup when an exact, provider-reported
   // cost is present (currently xAI's `cost_in_usd_ticks` — see extractExactCostUsd).
   const exactCostUsd = extractExactCostUsd(tokens);
-  if (exactCostUsd !== null) return exactCostUsd;
+  if (exactCostUsd !== null) return { costUsd: exactCostUsd, priced: true };
 
   try {
     const { getPricingForModel } = await import("@/lib/db/settings");
@@ -206,23 +219,37 @@ export async function calculateCost(
         }
       }
     }
-    if (!pricing) return 0;
+    // No pricing row anywhere — this is the #12341 case (e.g. a provider's own
+    // routing alias such as "auto" that has no catalog price). Report it as
+    // unpriced rather than a bare $0 so budget enforcement can fail closed.
+    if (!pricing) return { costUsd: 0, priced: false };
 
     const pricingRecord =
       pricing && typeof pricing === "object" && !Array.isArray(pricing)
         ? (pricing as Record<string, unknown>)
         : {};
-    return computeCostFromPricing(pricingRecord, tokens, {
+    const costUsd = computeCostFromPricing(pricingRecord, tokens, {
       provider,
       model,
       ...options,
     });
+    return { costUsd, priced: true };
   } catch (error) {
     console.error("Error calculating cost:", error);
-    return 0;
+    return { costUsd: 0, priced: false };
   }
 }
 
+export async function calculateCost(
+  provider: string,
+  model: string,
+  tokens: Record<string, number | undefined> | null | undefined,
+  options: CostCalculationOptions = {}
+): Promise<number> {
+  const result = await calculateCostDetailed(provider, model, tokens, options);
+  return result.costUsd;
+}
+
 type ModalPricing = Record<string, unknown>;
 
 /** Per-image cost: flat per-image × n. 0 when pricing/usage absent. */

tests/unit/api-key-budget-alias-auto-12341.test.ts

@@ -0,0 +1,113 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+
+const TEST_DATA_DIR = fs.mkdtempSync(path.join(os.tmpdir(), "omniroute-api-key-budget-alias-"));
+process.env.DATA_DIR = TEST_DATA_DIR;
+process.env.API_KEY_SECRET = process.env.API_KEY_SECRET || "budget-alias-test-secret";
+
+const core = await import("../../src/lib/db/core.ts");
+const apiKeysDb = await import("../../src/lib/db/apiKeys.ts");
+const usageHistory = await import("../../src/lib/usage/usageHistory.ts");
+const usageLimits = await import("../../src/lib/usage/apiKeyUsageLimits.ts");
+
+const NOW = Date.parse("2026-06-19T20:00:00.000Z");
+
+async function resetStorage() {
+  core.resetDbInstance();
+  apiKeysDb.resetApiKeyState();
+  usageHistory.clearPendingRequests();
+  fs.rmSync(TEST_DATA_DIR, { recursive: true, force: true, maxRetries: 5, retryDelay: 100 });
+  fs.mkdirSync(TEST_DATA_DIR, { recursive: true });
+}
+
+test.beforeEach(async () => {
+  await resetStorage();
+});
+
+test.after(() => {
+  core.resetDbInstance();
+  apiKeysDb.resetApiKeyState();
+  fs.rmSync(TEST_DATA_DIR, { recursive: true, force: true, maxRetries: 5, retryDelay: 100 });
+});
+
+async function makeMeteredKey() {
+  const created = await apiKeysDb.createApiKey("Budget Alias Key", "machine-budget-01");
+  await apiKeysDb.updateApiKeyPermissions(created.id, {
+    usageLimitEnabled: true,
+    dailyUsageLimitUsd: 10,
+    weeklyUsageLimitUsd: 50,
+  });
+  apiKeysDb.clearApiKeyCaches();
+  const metadata = await apiKeysDb.getApiKeyMetadata(created.key);
+  assert.ok(metadata);
+  return { created, metadata: metadata! };
+}
+
+test("BUG #12341: a real, billable completion routed through cursor/auto (unpriced) must not silently pass the daily budget cap as $0", async () => {
+  const { created, metadata } = await makeMeteredKey();
+
+  // Cursor's own default routing alias ("Auto (current, default)") has no
+  // pricing row anywhere — this is real, mainstream billable traffic, not an
+  // edge case.
+  await usageHistory.saveRequestUsage({
+    provider: "cursor",
+    model: "auto",
+    apiKeyId: created.id,
+    apiKeyName: "Budget Alias Key",
+    tokens: { input: 1_000_000, output: 1_000_000 },
+    success: true,
+    timestamp: "2026-06-19T12:00:00.000Z",
+  });
+
+  const status = await usageLimits.getApiKeyUsageLimitStatus(
+    { ...metadata, allowedConnections: null },
+    { now: () => NOW }
+  );
+
+  // Fail closed (#12341): unpriced usage in a window with a configured limit
+  // must flip the window to exceeded, even though the naive USD total is $0.
+  assert.equal(status.dailySpentUsd, 0, "cost stays $0 — no pricing row exists for cursor/auto");
+  assert.equal(
+    status.dailyHasUnpricedUsage,
+    true,
+    "status must flag that unpriced usage was seen in the daily window"
+  );
+  assert.equal(
+    status.dailyExceeded,
+    true,
+    "enforcement must fail closed instead of silently allowing unlimited unpriced usage"
+  );
+});
+
+test("control: a priced model routed at the same tokens does NOT trip fail-closed enforcement", async () => {
+  const { updatePricing } = await import("@/lib/db/settings");
+  await updatePricing({
+    openai: {
+      "gpt-4o": { input: 1, cached: 1, output: 1, reasoning: 1, cache_creation: 1 },
+    },
+  });
+
+  const { created, metadata } = await makeMeteredKey();
+
+  await usageHistory.saveRequestUsage({
+    provider: "openai",
+    model: "gpt-4o",
+    apiKeyId: created.id,
+    apiKeyName: "Budget Alias Key",
+    tokens: { input: 1_000_000, output: 0 },
+    success: true,
+    timestamp: "2026-06-19T12:00:00.000Z",
+  });
+
+  const status = await usageLimits.getApiKeyUsageLimitStatus(
+    { ...metadata, allowedConnections: null },
+    { now: () => NOW }
+  );
+
+  assert.equal(status.dailySpentUsd, 1);
+  assert.equal(status.dailyHasUnpricedUsage, false);
+  assert.equal(status.dailyExceeded, false);
+});

tests/unit/costcalculator-auto-alias-12341.test.ts

@@ -0,0 +1,42 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+import {
+  calculateCost,
+  calculateCostDetailed,
+  normalizeModelName,
+} from "../../src/lib/usage/costCalculator.ts";
+import { getDefaultPricing } from "../../src/shared/constants/pricing.ts";
+
+const BILLABLE_TOKENS = { input: 1_000_000, output: 1_000_000 };
+const PROVIDERS_WITH_UNPRICED_AUTO_MODEL = ["cursor", "factory", "trae", "dify", "llm-kiwi"];
+
+test('normalizeModelName is a no-op for a bare alias like "auto"', () => {
+  assert.equal(normalizeModelName("auto"), "auto");
+});
+
+test('no pricing source carries an entry for the literal "auto" model id, for providers whose registry offers it as a real model', () => {
+  const pricing = getDefaultPricing() as Record<string, Record<string, unknown>>;
+  for (const provider of PROVIDERS_WITH_UNPRICED_AUTO_MODEL) {
+    const providerPricing = pricing[provider];
+    assert.ok(!providerPricing || !providerPricing["auto"], `expected no DEFAULT_PRICING entry for ${provider}/auto`);
+  }
+});
+
+test('calculateCost() still returns $0 for a real, billable completion routed through the unpriced "auto" alias (unchanged legacy contract)', async () => {
+  const cost = await calculateCost("cursor", "auto", BILLABLE_TOKENS);
+  assert.equal(cost, 0, "calculateCost's numeric contract is unchanged — $0 for unpriced usage");
+});
+
+test('#12341 fix: calculateCostDetailed() flags the "auto" alias as unpriced instead of a bare, indistinguishable $0', async () => {
+  for (const provider of PROVIDERS_WITH_UNPRICED_AUTO_MODEL) {
+    const result = await calculateCostDetailed(provider, "auto", BILLABLE_TOKENS);
+    assert.equal(result.costUsd, 0, `expected $0 for ${provider}/auto`);
+    assert.equal(result.priced, false, `expected ${provider}/auto to be reported as unpriced`);
+  }
+});
+
+test("control: calculateCostDetailed() DOES price a normal, non-alias model correctly and reports it as priced", async () => {
+  const result = await calculateCostDetailed("openai", "gpt-4o", BILLABLE_TOKENS);
+  assert.ok(result.costUsd > 0, `expected a known model to price above $0, got ${result.costUsd}`);
+  assert.equal(result.priced, true);
+});