diff --git a/frontend/src/composables/__tests__/antigravityMappings.retry.spec.ts b/frontend/src/composables/__tests__/antigravityMappings.retry.spec.ts
new file mode 100644
index 0000000000..4f19e685b8
--- /dev/null
+++ b/frontend/src/composables/__tests__/antigravityMappings.retry.spec.ts
@@ -0,0 +1,50 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+
+const getMapping = vi.hoisted(() => vi.fn())
+vi.mock('@/api/admin/accounts', () => ({ getAntigravityDefaultModelMapping: getMapping }))
+
+beforeEach(() => {
+  vi.resetModules()
+  getMapping.mockReset()
+  vi.spyOn(console, 'warn').mockImplementation(() => {})
+})
+afterEach(() => vi.restoreAllMocks())
+
+describe('Antigravity default mapping cache', () => {
+  it('retries after a failed fetch rather than caching the empty fallback', async () => {
+    getMapping.mockRejectedValueOnce(new Error('offline')).mockResolvedValueOnce({ alias: 'upstream-model' })
+    const { fetchAntigravityDefaultMappings: fetch } = await import('../useModelWhitelist')
+    expect(await fetch()).toEqual([])
+    expect(await fetch()).toEqual([{ from: 'alias', to: 'upstream-model' }])
+    expect(getMapping).toHaveBeenCalledTimes(2)
+  })
+
+  it('caches a successful mapping', async () => {
+    getMapping.mockResolvedValue({ alias: 'upstream-model' })
+    const { fetchAntigravityDefaultMappings: fetch } = await import('../useModelWhitelist')
+    expect(await fetch()).toEqual([{ from: 'alias', to: 'upstream-model' }])
+    expect(await fetch()).toEqual([{ from: 'alias', to: 'upstream-model' }])
+    expect(getMapping).toHaveBeenCalledTimes(1)
+  })
+
+  it('still caches a successful empty mapping', async () => {
+    getMapping.mockResolvedValue({})
+    const { fetchAntigravityDefaultMappings: fetch } = await import('../useModelWhitelist')
+    expect(await fetch()).toEqual([])
+    expect(await fetch()).toEqual([])
+    expect(getMapping).toHaveBeenCalledTimes(1)
+  })
+
+  it('does not erase a successful concurrent result when an older request fails', async () => {
+    let reject!: (error: Error) => void
+    getMapping.mockImplementationOnce(() => new Promise((_, fail) => { reject = fail }))
+      .mockResolvedValueOnce({ alias: 'upstream-model' })
+    const { fetchAntigravityDefaultMappings: fetch } = await import('../useModelWhitelist')
+    const older = fetch()
+    await fetch()
+    reject(new Error('offline'))
+    expect(await older).toEqual([])
+    expect(await fetch()).toEqual([{ from: 'alias', to: 'upstream-model' }])
+    expect(getMapping).toHaveBeenCalledTimes(2)
+  })
+})
diff --git a/frontend/src/composables/useModelWhitelist.ts b/frontend/src/composables/useModelWhitelist.ts
index 80696b28f8..0b312d21bf 100644
--- a/frontend/src/composables/useModelWhitelist.ts
+++ b/frontend/src/composables/useModelWhitelist.ts
@@ -413,7 +413,7 @@ export async function fetchAntigravityDefaultMappings(): Promise<{ from: string;
     _antigravityDefaultMappingsCache = Object.entries(mapping).map(([from, to]) => ({ from, to }))
   } catch (e) {
     console.warn('[fetchAntigravityDefaultMappings] API failed, using empty fallback', e)
-    _antigravityDefaultMappingsCache = []
+    return []
   }
   return _antigravityDefaultMappingsCache
 }