fix(quota): coalesce provider usage refreshes

packages/web/server/lib/quota/providers/claude/index.test.js

@@ -67,6 +67,24 @@ describe('Claude quota provider', () => {
     expect(result.usage.windows['5h'].usedPercent).toBe(5);
   });
 
+  it('coalesces concurrent refreshes into one Anthropic request', async () => {
+    let resolveResponse;
+    const fetchMock = vi.fn().mockReturnValue(new Promise((resolve) => {
+      resolveResponse = resolve;
+    }));
+    vi.stubGlobal('fetch', fetchMock);
+
+    const first = fetchQuota();
+    const second = fetchQuota();
+    resolveResponse(jsonResponse(PAYLOAD));
+
+    const [firstResult, secondResult] = await Promise.all([first, second]);
+
+    expect(fetchMock).toHaveBeenCalledTimes(1);
+    expect(firstResult.ok).toBe(true);
+    expect(secondResult.ok).toBe(true);
+  });
+
   it('keeps serving the last good values while Anthropic rate limits', async () => {
     const fetchMock = vi.fn()
       .mockResolvedValueOnce(jsonResponse(PAYLOAD))

packages/web/server/lib/quota/providers/index.js

@@ -158,6 +158,8 @@ const registry = {
   }
 };
 
+const pendingFetches = new Map();
+
 export const listConfiguredQuotaProviders = () => {
   const configured = [];
 
@@ -174,7 +176,7 @@ export const listConfiguredQuotaProviders = () => {
   return configured;
 };
 
-export const fetchQuotaForProvider = async (providerId) => {
+const fetchQuotaForProviderUncoalesced = async (providerId) => {
   const provider = registry[providerId];
 
   if (!provider) {
@@ -200,6 +202,17 @@ export const fetchQuotaForProvider = async (providerId) => {
   }
 };
 
+export const fetchQuotaForProvider = (providerId) => {
+  const existing = pendingFetches.get(providerId);
+  if (existing) return existing;
+
+  const pending = fetchQuotaForProviderUncoalesced(providerId).finally(() => {
+    if (pendingFetches.get(providerId) === pending) pendingFetches.delete(providerId);
+  });
+  pendingFetches.set(providerId, pending);
+  return pending;
+};
+
 export const fetchClaudeQuota = claude.fetchQuota;
 export const fetchOpenaiQuota = openai.fetchQuota;
 export const fetchGoogleQuota = google.fetchGoogleQuota;

packages/web/server/lib/quota/providers/index.test.js

@@ -1,7 +1,7 @@
 import { describe, expect, it } from 'vitest';
 
 import * as google from './google/index.js';
-import { listConfiguredQuotaProviders } from './index.js';
+import { fetchQuotaForProvider, listConfiguredQuotaProviders } from './index.js';
 
 describe('quota provider registry', () => {
   it('exposes google provider configuration helpers through the provider module', () => {
@@ -14,4 +14,13 @@ describe('quota provider registry', () => {
   it('can list configured providers without missing provider exports', () => {
     expect(() => listConfiguredQuotaProviders()).not.toThrow();
   });
+
+  it('coalesces concurrent refreshes by provider ID', async () => {
+    const first = fetchQuotaForProvider('unsupported-test-provider');
+    const second = fetchQuotaForProvider('unsupported-test-provider');
+
+    expect(first).toBe(second);
+    await first;
+    expect(fetchQuotaForProvider('unsupported-test-provider')).not.toBe(first);
+  });
 });