fix(cliproxy): preserve Claude fallback when quota is unavailable

src/cliproxy/quota-manager.ts

@@ -281,7 +281,7 @@ function calculateQuotaPercent(quota: ManagedQuotaResult): number | null {
 export async function findHealthyAccount(
   provider: CLIProxyProvider,
   exclude: string[]
-): Promise<{ id: string; tier: string; lastQuota: number } | null> {
+): Promise<{ id: string; tier: string; lastQuota: number | null } | null> {
   if (!isManagedQuotaProvider(provider)) {
     return null;
   }
@@ -309,7 +309,7 @@ export async function findHealthyAccount(
         quota = await fetchQuotaWithDedup(provider, account.id);
       }
 
-      const avgQuota = calculateQuotaPercent(quota) ?? 0;
+      const avgQuota = calculateQuotaPercent(quota);
 
       return {
         id: account.id,
@@ -320,22 +320,24 @@ export async function findHealthyAccount(
     10
   );
 
-  // Filter by threshold
-  const healthy = withQuotas.filter((a) => a.lastQuota >= threshold);
-  if (healthy.length === 0) return null;
+  // Prefer accounts with known healthy quota. If all remaining accounts have unavailable
+  // quota data, fall back to those unknown-but-usable accounts instead of treating them as 0%.
+  const healthy = withQuotas.filter((a) => a.lastQuota !== null && a.lastQuota >= threshold);
+  const selectable = healthy.length > 0 ? healthy : withQuotas.filter((a) => a.lastQuota === null);
+  if (selectable.length === 0) return null;
 
   // Sort by tier priority then quota descending
-  healthy.sort((a, b) => {
+  selectable.sort((a, b) => {
     const tierA = tierPriority.indexOf(a.tier);
     const tierB = tierPriority.indexOf(b.tier);
     const tierOrderA = tierA === -1 ? 999 : tierA;
     const tierOrderB = tierB === -1 ? 999 : tierB;
 
     if (tierOrderA !== tierOrderB) return tierOrderA - tierOrderB;
-    return b.lastQuota - a.lastQuota;
+    return (b.lastQuota ?? -1) - (a.lastQuota ?? -1);
   });
 
-  return healthy[0];
+  return selectable[0];
 }
 
 /**

tests/unit/cliproxy/account-safety-quota-exhaustion.test.ts

@@ -9,7 +9,7 @@
  * - Email masking
  */
 
-import { describe, it, expect, beforeEach, afterEach } from 'bun:test';
+import { describe, it, expect, beforeEach, afterEach, mock } from 'bun:test';
 import * as fs from 'fs';
 import * as os from 'os';
 import * as path from 'path';
@@ -18,18 +18,22 @@ import {
   writeQuotaWarning,
   maskEmail,
 } from '../../../src/cliproxy/account-safety';
+import { sanitizeEmail } from '../../../src/cliproxy/auth-utils';
 
 // Setup test isolation
 let tmpDir: string;
 let origCcsHome: string | undefined;
+let originalFetch: typeof fetch;
 
 beforeEach(() => {
   tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'ccs-test-exhaust-'));
   origCcsHome = process.env.CCS_HOME;
   process.env.CCS_HOME = tmpDir;
+  originalFetch = global.fetch;
 });
 
 afterEach(() => {
+  global.fetch = originalFetch;
   if (origCcsHome !== undefined) {
     process.env.CCS_HOME = origCcsHome;
   } else {
@@ -61,6 +65,25 @@ function writeConfig(quotaConfig: unknown): void {
   );
 }
 
+function writeClaudeAuth(accountId: string, accessToken: string): void {
+  const authDir = path.join(tmpDir, '.ccs', 'cliproxy', 'auth');
+  const tokenFile = `claude-${sanitizeEmail(accountId)}.json`;
+  fs.mkdirSync(authDir, { recursive: true });
+  fs.writeFileSync(
+    path.join(authDir, tokenFile),
+    JSON.stringify(
+      {
+        access_token: accessToken,
+        expired: '2099-01-01T00:00:00.000Z',
+        type: 'claude',
+        email: accountId,
+      },
+      null,
+      2
+    )
+  );
+}
+
 describe('Quota Exhaustion Handlers', () => {
   describe('writeQuotaWarning', () => {
     it('should write to stderr with box format', async () => {
@@ -230,6 +253,69 @@ describe('Quota Exhaustion Handlers', () => {
       expect(result.reason).toContain('no alternatives');
     });
 
+    it('should switch Claude accounts when fallback quota is unavailable but auth is valid', async () => {
+      writeRegistry({
+        claude: {
+          default: 'exhausted@example.com',
+          accounts: {
+            'exhausted@example.com': {
+              email: 'exhausted@example.com',
+              tokenFile: `claude-${sanitizeEmail('exhausted@example.com')}.json`,
+            },
+            'fallback@example.com': {
+              email: 'fallback@example.com',
+              tokenFile: `claude-${sanitizeEmail('fallback@example.com')}.json`,
+            },
+          },
+        },
+      });
+
+      writeConfig({
+        mode: 'auto',
+        auto: {
+          tier_priority: ['ultra', 'pro', 'free'],
+          exhaustion_threshold: 5,
+          cooldown_minutes: 10,
+          preflight_check: true,
+        },
+        runtime_monitor: {
+          enabled: true,
+          normal_interval_seconds: 300,
+          critical_interval_seconds: 60,
+          warn_threshold: 20,
+          exhaustion_threshold: 5,
+          cooldown_minutes: 10,
+        },
+      });
+
+      writeClaudeAuth('exhausted@example.com', 'exhausted-token');
+      writeClaudeAuth('fallback@example.com', 'fallback-token');
+
+      global.fetch = mock((_url: string, options?: RequestInit) => {
+        const authHeader = new Headers(options?.headers).get('Authorization') ?? '';
+        if (authHeader === 'Bearer fallback-token') {
+          return Promise.resolve(
+            new Response(
+              JSON.stringify({
+                error: {
+                  message: 'OAuth authentication is currently not supported.',
+                },
+              }),
+              { status: 401, headers: { 'Content-Type': 'application/json' } }
+            )
+          );
+        }
+
+        return Promise.resolve(new Response('', { status: 500 }));
+      }) as typeof fetch;
+
+      const result = await handleQuotaExhaustion('claude', 'exhausted@example.com', 10);
+      const { getDefaultAccount } = await import('../../../src/cliproxy/account-manager');
+
+      expect(result.switchedTo).toBe('fallback@example.com');
+      expect(getDefaultAccount('claude')?.id).toBe('fallback@example.com');
+    });
+
     it('should write warning to stderr', async () => {
       writeRegistry({
         agy: {

tests/unit/cliproxy/quota-fetcher-claude.test.ts

@@ -395,6 +395,101 @@ describe('Claude Quota Fetcher', () => {
       expect(result.coreUsage?.weekly).toBeNull();
     });
 
+    it('treats root-level OAuth-unsupported 401 message as policy-limits unavailable', async () => {
+      createClaudeAccount('claude-oauth-root-message@example.com', {
+        access_token: 'oauth-token',
+        expired: '2099-01-01T00:00:00.000Z',
+        type: 'claude',
+      });
+
+      global.fetch = mock(() =>
+        Promise.resolve(
+          new Response(
+            JSON.stringify({
+              message: 'OAuth authentication is currently not supported.',
+            }),
+            { status: 401, headers: { 'Content-Type': 'application/json' } }
+          )
+        )
+      ) as typeof fetch;
+
+      const result = await fetchClaudeQuota('claude-oauth-root-message@example.com');
+
+      expect(result.success).toBe(true);
+      expect(result.needsReauth).toBeUndefined();
+      expect(result.windows).toHaveLength(0);
+      expect(result.coreUsage?.fiveHour).toBeNull();
+      expect(result.coreUsage?.weekly).toBeNull();
+    });
+
+    it('treats plain-text OAuth-unsupported 401 as policy-limits unavailable', async () => {
+      createClaudeAccount('claude-oauth-plaintext@example.com', {
+        access_token: 'oauth-token',
+        expired: '2099-01-01T00:00:00.000Z',
+        type: 'claude',
+      });
+
+      global.fetch = mock(() =>
+        Promise.resolve(
+          new Response('OAuth authentication is currently not supported.', { status: 401 })
+        )
+      ) as typeof fetch;
+
+      const result = await fetchClaudeQuota('claude-oauth-plaintext@example.com');
+
+      expect(result.success).toBe(true);
+      expect(result.needsReauth).toBeUndefined();
+      expect(result.windows).toHaveLength(0);
+      expect(result.coreUsage?.fiveHour).toBeNull();
+      expect(result.coreUsage?.weekly).toBeNull();
+    });
+
+    it('keeps non-matching 401 payloads in the reauth path', async () => {
+      createClaudeAccount('claude-auth-other-401@example.com', {
+        access_token: 'oauth-token',
+        expired: '2099-01-01T00:00:00.000Z',
+        type: 'claude',
+      });
+
+      global.fetch = mock(() =>
+        Promise.resolve(
+          new Response(
+            JSON.stringify({
+              error: {
+                type: 'authentication_error',
+                message: 'Token revoked.',
+              },
+            }),
+            { status: 401, headers: { 'Content-Type': 'application/json' } }
+          )
+        )
+      ) as typeof fetch;
+
+      const result = await fetchClaudeQuota('claude-auth-other-401@example.com');
+
+      expect(result.success).toBe(false);
+      expect(result.needsReauth).toBe(true);
+      expect(result.error).toContain('Authentication');
+    });
+
+    it('treats 404 policy limits responses as unavailable but successful', async () => {
+      createClaudeAccount('claude-policy-limits-404@example.com', {
+        access_token: 'oauth-token',
+        expired: '2099-01-01T00:00:00.000Z',
+        type: 'claude',
+      });
+
+      global.fetch = mock(() => Promise.resolve(new Response('', { status: 404 }))) as typeof fetch;
+
+      const result = await fetchClaudeQuota('claude-policy-limits-404@example.com');
+
+      expect(result.success).toBe(true);
+      expect(result.needsReauth).toBeUndefined();
+      expect(result.windows).toHaveLength(0);
+      expect(result.coreUsage?.fiveHour).toBeNull();
+      expect(result.coreUsage?.weekly).toBeNull();
+    });
+
     it('fails fast when auth file has no token', async () => {
       createClaudeAccount('claude-missing@example.com', {
         access_token: '   ',

ui/src/components/cliproxy/provider-editor/account-item.tsx

@@ -42,6 +42,7 @@ import {
 import { PRIVACY_BLUR_CLASS } from '@/contexts/privacy-context';
 import { useAccountQuota, useCliproxyStats } from '@/hooks/use-cliproxy-stats';
 import { QuotaTooltipContent } from '@/components/shared/quota-tooltip-content';
+import { useTranslation } from 'react-i18next';
 import type { AccountItemProps } from './types';
 
 /**
@@ -106,6 +107,7 @@ export function AccountItem({
   selected,
   onSelectChange,
 }: AccountItemProps) {
+  const { t } = useTranslation();
   const normalizedProvider = account.provider.toLowerCase();
   const isCodexProvider = normalizedProvider === 'codex';
   const isClaudeProvider = normalizedProvider === 'claude' || normalizedProvider === 'anthropic';
@@ -436,7 +438,7 @@ export function AccountItem({
                 className="text-[10px] h-5 px-2 gap-1 border-muted-foreground/50 text-muted-foreground"
               >
                 <HelpCircle className="w-3 h-3" />
-                No limits
+                {t('accountCard.quotaUnavailable')}
               </Badge>
             </div>
           ) : quota?.needsReauth ? (