diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index 80ebfb7..55d236f 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -1,6 +1,7 @@
 import { BrowserRouter, Routes, Route, Link, useLocation, Navigate } from 'react-router-dom'
-import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
+import { QueryClient, QueryClientProvider, QueryCache, MutationCache } from '@tanstack/react-query'
 import { ErrorBoundary } from './components/ErrorBoundary'
+import { showApiError } from './lib/toast'
 import Dashboard from './pages/Dashboard'
 import MealDetail from './pages/MealDetail'
 import Pantry from './pages/Pantry'
@@ -10,7 +11,24 @@ import RecipeDetail from './pages/RecipeDetail'
 import ShoppingList from './pages/ShoppingList'
 import NotFound from './pages/NotFound'
 
-const queryClient = new QueryClient()
+const queryClient = new QueryClient({
+  defaultOptions: {
+    queries: {
+      retry: 1,
+      refetchOnWindowFocus: false,
+    },
+  },
+  queryCache: new QueryCache({
+    onError: (error) => {
+      showApiError(error, 'Failed to load data')
+    },
+  }),
+  mutationCache: new MutationCache({
+    onError: (error) => {
+      showApiError(error)
+    },
+  }),
+})
 
 function Navigation() {
   const location = useLocation()
diff --git a/frontend/src/lib/toast.tsx b/frontend/src/lib/toast.tsx
index eb2e856..5808944 100644
--- a/frontend/src/lib/toast.tsx
+++ b/frontend/src/lib/toast.tsx
@@ -1,5 +1,55 @@
 import toast from 'react-hot-toast';
 
+export type ApiError = unknown;
+
+function isHttpError(err: unknown): err is { response?: { data?: { detail?: unknown } }; message?: string } {
+  return typeof err === 'object' && err !== null && 'response' in (err as object);
+}
+
+function getFastApiDetail(err: unknown): string | null {
+  if (!isHttpError(err)) return null;
+  const detail = err.response?.data?.detail;
+  if (typeof detail === 'string') return detail;
+  if (Array.isArray(detail) && detail.length > 0) {
+    const first = detail[0] as { msg?: string } | string;
+    if (typeof first === 'string') return first;
+    if (typeof first === 'object' && first !== null && 'msg' in first) {
+      return (first as { msg?: string }).msg ?? null;
+    }
+  }
+  return null;
+}
+
+function getNetworkMessage(err: unknown): string | null {
+  if (!isHttpError(err)) return null;
+  const msg = err.message;
+  if (typeof msg === 'string' && msg && msg !== 'Network Error') return msg;
+  return null;
+}
+
+/**
+ * Normalize any thrown value (FastAPI HTTP error, network error, JS error)
+ * to a short user-facing string. Falls back to a generic message so we
+ * never surface a raw "[object Object]" or stack trace.
+ */
+export function extractErrorMessage(err: unknown, fallback = 'Something went wrong'): string {
+  return (
+    getFastApiDetail(err) ??
+    getNetworkMessage(err) ??
+    (err instanceof Error ? err.message : null) ??
+    fallback
+  );
+}
+
+/**
+ * Show a toast for any error. Use as the MutationCache/QueryCache
+ * global onError, or call directly from per-mutation onError handlers
+ * that need a normalized message.
+ */
+export function showApiError(err: unknown, fallback?: string): void {
+  showToast.error(extractErrorMessage(err, fallback));
+}
+
 export const showToast = {
   success: (message: string) => toast.success(message),
   error: (message: string) => toast.error(message),
diff --git a/frontend/src/pages/Dashboard.tsx b/frontend/src/pages/Dashboard.tsx
index ee5f381..abb2a69 100644
--- a/frontend/src/pages/Dashboard.tsx
+++ b/frontend/src/pages/Dashboard.tsx
@@ -6,7 +6,7 @@ import {
   GripVertical, X
 } from 'lucide-react'
 import toast from 'react-hot-toast'
-import { showToast } from '../lib/toast'
+import { showToast, showApiError } from '../lib/toast'
 import {
   DragDropContext,
   Droppable,
@@ -282,8 +282,8 @@ function VoteEmailButton() {
       const res = await mealPlannerApi.admin.triggerOrchestrate('email')
       const status = res.data?.status || res.data?.message || 'sent'
       toast.success(status)
-    } catch (err: any) {
-      toast.error(err?.response?.data?.detail || 'Failed to send vote emails')
+    } catch (err) {
+      showApiError(err, 'Failed to send vote emails')
     } finally {
       setSendingVoteEmail(false)
     }
@@ -316,8 +316,8 @@ export default function Dashboard() {
       await mealPlannerApi.meals.moveItem(itemId, newDay, newType)
       toast.success('Meal moved')
       queryClient.invalidateQueries({ queryKey: ['mealPlan'] })
-    } catch (err: any) {
-      toast.error(err?.response?.data?.detail || 'Failed to move meal')
+    } catch {
+      // Error toast fires from the global MutationCache handler.
     }
   }
 
@@ -334,8 +334,8 @@ export default function Dashboard() {
       await mealPlannerApi.meals.approveItem(itemId)
       toast.success('Meal approved')
       queryClient.invalidateQueries({ queryKey: ['mealPlan'] })
-    } catch (err: any) {
-      toast.error(err?.response?.data?.detail || 'Failed to approve meal')
+    } catch {
+      // Error toast fires from the global MutationCache handler.
     }
   }
 
@@ -344,8 +344,8 @@ export default function Dashboard() {
       await mealPlannerApi.meals.denyItem(itemId)
       toast.success('Meal denied')
       queryClient.invalidateQueries({ queryKey: ['mealPlan'] })
-    } catch (err: any) {
-      toast.error(err?.response?.data?.detail || 'Failed to deny meal')
+    } catch {
+      // Error toast fires from the global MutationCache handler.
     }
   }
 
@@ -367,13 +367,13 @@ export default function Dashboard() {
             )
             queryClient.invalidateQueries({ queryKey: ['mealPlan'] })
             toast.success('Slot filled with a new meal')
-          } catch (err: any) {
-            toast.error(err?.response?.data?.detail || 'Failed to refill slot')
+          } catch (err) {
+            showApiError(err, 'Failed to refill slot')
           }
         }
       )
-    } catch (err: any) {
-      toast.error(err?.response?.data?.detail || 'Failed to delete meal')
+    } catch {
+      // Error toast fires from the global MutationCache handler.
     }
   }
 
@@ -383,8 +383,8 @@ export default function Dashboard() {
       await mealPlannerApi.meals.generateItem(mealPlan.id, dayIndex + 1, mealType)
       toast.success('Meal generated')
       queryClient.invalidateQueries({ queryKey: ['mealPlan'] })
-    } catch (err: any) {
-      toast.error(err?.response?.data?.detail || 'Failed to generate meal')
+    } catch {
+      // Error toast fires from the global MutationCache handler.
     }
   }
 
@@ -435,7 +435,10 @@ export default function Dashboard() {
           </div>
         </div>
         <div className="flex items-center gap-3">
-          <Badge variant={statusVariant}>
+          <Badge
+            variant={statusVariant}
+            aria-label={`Plan status: ${mealPlan.status.replace(/_/g, ' ')}`}
+          >
             {mealPlan.status.replace(/_/g, ' ')}
           </Badge>
           {mealPlan.total_estimated_cost !== undefined && (
diff --git a/frontend/src/pages/MealDetail.tsx b/frontend/src/pages/MealDetail.tsx
index bffd713..619317b 100644
--- a/frontend/src/pages/MealDetail.tsx
+++ b/frontend/src/pages/MealDetail.tsx
@@ -113,9 +113,6 @@ export default function MealDetail() {
       setEditingFeedback(false)
       showToast.success('Feedback saved!')
     },
-    onError: () => {
-      showToast.error('Failed to save feedback. Please try again.')
-    },
   })
 
   if (isLoading) {
diff --git a/frontend/src/pages/Pantry.tsx b/frontend/src/pages/Pantry.tsx
index 0f254ef..591854a 100644
--- a/frontend/src/pages/Pantry.tsx
+++ b/frontend/src/pages/Pantry.tsx
@@ -9,7 +9,7 @@ import { Input } from '../components/ui/Input'
 import { Select } from '../components/ui/Select'
 import { Skeleton, SkeletonText } from '../components/ui/Skeleton'
 import { EmptyState } from '../components/ui/EmptyState'
-import { showToast } from '../lib/toast'
+import { showToast, showApiError } from '../lib/toast'
 
 const AISLE_OPTIONS = [
   { value: '', label: 'Select aisle…' },
@@ -62,9 +62,6 @@ export default function Pantry() {
       setAisle('')
       showToast.success('Item added to pantry')
     },
-    onError: () => {
-      showToast.error('Failed to add item')
-    },
   })
 
   const removeMutation = useMutation({
@@ -74,10 +71,6 @@ export default function Pantry() {
       showToast.success('Item removed')
       setRemoveId(null)
     },
-    onError: () => {
-      showToast.error('Failed to remove item')
-      setRemoveId(null)
-    },
   })
 
   async function handleRemove(item: HomePantryItem) {
@@ -100,13 +93,13 @@ export default function Pantry() {
             })
             queryClient.invalidateQueries({ queryKey: ['pantry'] })
             showToast.success('Item restored')
-          } catch {
-            showToast.error('Failed to restore item')
+          } catch (err) {
+            showApiError(err, 'Failed to restore item')
           }
         }
       )
     } catch {
-      showToast.error('Failed to remove item')
+      // Error toast fires from the global MutationCache handler.
     } finally {
       setRemoveId(null)
     }
@@ -133,7 +126,7 @@ export default function Pantry() {
         // refresh ingredient list so next add sees it
         await queryClient.invalidateQueries({ queryKey: ['ingredients'] })
       } catch {
-        showToast.error('Failed to create ingredient')
+        // Error toast fires from the global MutationCache handler.
         return
       }
     }