fix: surface Spotify quota exhaustion

Co-Authored-By: Claude <noreply@anthropic.com>

backend/app/pipeline/orchestrator.py

@@ -38,6 +38,8 @@ from app.ports.protocols import (
 RERANK_FALLBACK_CODE = "rerank_fallback"
 RERANK_FALLBACK_MESSAGE = "Ranking output was invalid, so grounded results are shown instead."
 RERANK_FALLBACK_JUSTIFICATION = "Selected as a grounded match for your request."
+QUOTA_ERROR_CODE = "quota_exhausted"
+QUOTA_ERROR_MESSAGE = "Spotify's Development Mode quota is temporarily exhausted."
 
 
 class _TrackSelection:
@@ -140,10 +142,8 @@ class RecommendationPipeline:
             return
         except CatalogQuotaExhaustedError:
             yield PipelineErrorEvent(
-                code="quota_exhausted",
-                message=(
-                    "Spotify request quota was exhausted before recommendations could be prepared."
-                ),
+                code=QUOTA_ERROR_CODE,
+                message=QUOTA_ERROR_MESSAGE,
             )
             return
         except SpotifyError:
@@ -158,9 +158,16 @@ class RecommendationPipeline:
             candidate_count=len(intent.candidates),
         )
 
+        try:
             pool = await self._grounded_pool(
                 session_id, catalog, intent, taste, deadline_at, seeded_pool
             )
+        except CatalogQuotaExhaustedError:
+            yield PipelineErrorEvent(
+                code=QUOTA_ERROR_CODE,
+                message=QUOTA_ERROR_MESSAGE,
+            )
+            return
         if not pool:
             yield PipelineErrorEvent(
                 code="no_grounded_results",
@@ -209,6 +216,8 @@ class RecommendationPipeline:
             self.settings.rerank_count + self.settings.rerank_pool_buffer,
             deadline_at,
         )
+        if not result.tracks and result.metrics.did_exhaust_quota:
+            raise CatalogQuotaExhaustedError
         if result.tracks:
             self.last_pools[session_id] = result.tracks
         return result.tracks

backend/tests/test_orchestrator.py

@@ -146,6 +146,30 @@ def test_intent_stage_failures_yield_one_typed_error_event() -> None:
     asyncio.run(run())
 
 
+def test_grounding_quota_yields_typed_error_instead_of_empty_results() -> None:
+    class QuotaCatalog(FakeCatalog):
+        """Exhaust the Spotify quota on the first grounding search."""
+
+        async def search_tracks(self, query: str, limit: int = 10) -> list[Track]:
+            self.search_call_count += 1
+            raise SpotifyQuotaExhaustedError(0.0, "QUOTA_EXCEEDED")
+
+    async def run() -> None:
+        track = _track("candidate", "Candidate Song")
+        catalog = QuotaCatalog(())
+        recommender = FakeRecommender([_intent(track)])
+
+        events = await _run_pipeline(catalog, recommender)
+
+        assert [event.type for event in events] == ["metadata", "error"]
+        assert isinstance(events[-1], PipelineErrorEvent)
+        assert events[-1].code == "quota_exhausted"
+        assert catalog.search_call_count == 1
+        assert recommender.rerank_call_count == 0
+
+    asyncio.run(run())
+
+
 def test_taste_failure_cancels_sibling_fetches() -> None:
     class FailingTasteCatalog(FakeCatalog):
         """Fail one taste request after all sibling requests have started."""

docs/logboek.md

@@ -514,3 +514,27 @@ Waarom:
   werkende versie 1 klik verderop hebben. Een runtime mode-switch in de
   app zelf zou een derde codepad zijn; twee instanties met elk 1 mode
   houden het ontwerp schoon.
+
+### Final polishing round
+
+Wat ik deed:
+
+- De laatste live-test gaf op de Spotify Search endpoint opnieuw
+  `QUOTA_EXCEEDED`, terwijl auth en de taste-profile calls wel werkten. De
+  pipeline toont dit nu als een `quota_exhausted` error in plaats van als nul
+  resultaten; de retry button verdwijnt en de demo-link blijft staan.
+- De eerdere aanname van een dagelijks resetmoment gecorrigeerd. Spotify deelt
+  Development Mode quota per developer-account en endpoint bucket, maar
+  publiceert de limieten en het reset window niet.
+
+Waarom:
+
+- Een quota error is geen geldige zoekopdracht met nul resultaten. Door deze
+  rate-limit issues lever ik op 12 augustus in: eerst één gecontroleerde
+  live-test, daarna direct de hand-in.
+
+Wat ik heb laten vallen of uitgesteld:
+
+- De structurele oplossing is een Spotify key met hogere quota. Dat is voor
+  deze PoC-assessment niet proportioneel; ik bouw geen slimme workaround en
+  live mode valt niet stil terug op fixtures.

docs/workflow.md

@@ -17,8 +17,8 @@ below. No cloud dev environment involved.
   the repo you are reading is the mirror and shows the same history and
   the same green CI.
 - CI runs on every push: ruff, mypy and pytest for the backend; typecheck,
-  lint, build and vitest for the frontend. It has been green since the
-  first commit.
+  lint, build and vitest for the frontend. One intermediate batch exposed
+  a test typing error; the next commit fixed it, and current main is green.
 
 ## Deployment
 

frontend/src/components/StreamError.vue

@@ -8,7 +8,9 @@ defineEmits<{ retry: [] }>()
 <template>
   <div class="error" role="alert" :data-error-code="code">
     <p>{{ message }}</p>
-    <button type="button" @click="$emit('retry')">{{ messages.streamErrorRetry }}</button>
+    <button v-if="code !== 'quota_exhausted'" type="button" @click="$emit('retry')">
+      {{ messages.streamErrorRetry }}
+    </button>
     <a v-if="demoUrl" class="demo-link" :href="demoUrl">
       {{ messages.streamErrorDemoInstance }}
     </a>

frontend/tests/resultPresentation.test.ts

@@ -166,6 +166,34 @@ describe('result presentation', () => {
     expect(onPick).toHaveBeenCalledWith('Focus')
   })
 
+  it('renders a quota error without retry and keeps the demo escape hatch', () => {
+    const turn: AssistantTurn = {
+      ...doneTurn(),
+      status: 'error',
+      tracks: [],
+      warnings: [],
+      error: {
+        type: 'error',
+        code: 'quota_exhausted',
+        message: "Spotify's Development Mode quota is temporarily exhausted.",
+      },
+      completion: null,
+    }
+    const demoUrl = 'https://demo.example.com'
+    const root = mountComponent(AssistantMessage, {
+      turn,
+      canSave: false,
+      demoUrl,
+    })
+    const alert = root.querySelector<HTMLElement>('[role="alert"]')
+    const demoLink = alert?.querySelector<HTMLAnchorElement>('a')
+
+    expect(alert?.dataset.errorCode).toBe('quota_exhausted')
+    expect(alert?.querySelector('button')).toBeNull()
+    expect(demoLink?.href).toBe(`${demoUrl}/`)
+    expect(demoLink?.textContent).toContain('Open the demo instance')
+  })
+
   it('renders a first-stage stream error with its code and message', () => {
     const turn: AssistantTurn = {
       ...doneTurn(),