diff --git a/frontend/src/__tests__/api.test.ts b/frontend/src/__tests__/api.test.ts
index 3c8d5733..3a381be0 100644
--- a/frontend/src/__tests__/api.test.ts
+++ b/frontend/src/__tests__/api.test.ts
@@ -372,11 +372,7 @@ describe('API Requests', () => {
         json: () => Promise.reject(new Error('parse error'))
       });
 
-      try {
-        await apiRequest('/test');
-      } catch (error) {
-        expect((error as { status?: number }).status).toBe(500);
-      }
+      await expect(apiRequest('/test')).rejects.toMatchObject({ status: 500 });
     });
 
     test('resolves a 204 No Content response to null', async () => {
diff --git a/go.mod b/go.mod
index 5fb3a2f6..abcf4fb6 100644
--- a/go.mod
+++ b/go.mod
@@ -59,7 +59,7 @@ require (
 	go.opentelemetry.io/otel/metric v1.45.0 // indirect
 	go.opentelemetry.io/otel/trace v1.45.0 // indirect
 	golang.org/x/crypto v0.58.0
-	golang.org/x/net v0.61.0 // indirect
+	golang.org/x/net v0.62.0 // indirect
 	golang.org/x/oauth2 v0.37.0
 	golang.org/x/sync v0.24.0
 	golang.org/x/sys v0.49.0 // indirect
diff --git a/go.sum b/go.sum
index 06deac0b..83df52e6 100644
--- a/go.sum
+++ b/go.sum
@@ -367,8 +367,8 @@ golang.org/x/crypto v0.58.0 h1:COkYLr4k7nDI4r6QtMML2AfzeIswWHAJthLS6K/M/54=
 golang.org/x/crypto v0.58.0/go.mod h1:Xh+kl5A+M0gMiWDytH2Hhr5Z7WbNCpv/eB/EFgfSk+w=
 golang.org/x/mod v0.42.0 h1:ICeL3t2L30ljSPHHxDnR4fqVcBt/zR2zJAb9juavmQg=
 golang.org/x/mod v0.42.0/go.mod h1:u5fzIrRInkL8MaO1cbRkUHT64v303YIT5KEqpNr7jRs=
-golang.org/x/net v0.61.0 h1:RR+6j/BTBCrggOLugxa+66R8FvoN6MHlzDlZIbN9YFw=
-golang.org/x/net v0.61.0/go.mod h1:WgDCOTH8iwtB66T4/GfI94AHo/hhdb7Hah9NDseQfiI=
+golang.org/x/net v0.62.0 h1:18ELalfM5+XNRwzM2nYqXsZQ9ByS1uhj2O/U7+5jqRY=
+golang.org/x/net v0.62.0/go.mod h1:WgDCOTH8iwtB66T4/GfI94AHo/hhdb7Hah9NDseQfiI=
 golang.org/x/oauth2 v0.37.0 h1:JUlcxA8oAtauLfiH8FX2/FkAWHAdi0QtGCGc+hofE98=
 golang.org/x/oauth2 v0.37.0/go.mod h1:IxwZNxUULJmpBFf9K/9NTMSIfZZuvuTy1gGxhigP/58=
 golang.org/x/sync v0.24.0 h1:iqiDrGoDgyuvAKrhLQthUEzU/R378N78gXbBjxed7oA=
diff --git a/internal/mocks/bare_panic_guard_test.go b/internal/mocks/bare_panic_guard_test.go
new file mode 100644
index 00000000..7ed3c4c7
--- /dev/null
+++ b/internal/mocks/bare_panic_guard_test.go
@@ -0,0 +1,113 @@
+package mocks
+
+import (
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"os"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// TestMocks_NoBarePanicOutsideTestReporter keeps #353 closed for code not yet
+// written. A mock that panics on a test-authoring error (a mistyped .Return,
+// say) ends the whole test binary: the remaining tests go unrun, TestMain
+// teardown is skipped, and the output is a stack trace instead of a failure
+// filed under the test's name. Such errors go through testReporter (see
+// report.go), whose fail method is the one place allowed to panic, and only
+// when no test is registered to report to.
+//
+// The check parses the package's non-test files, so a panic added to any
+// mock later fails here without editing this test.
+func TestMocks_NoBarePanicOutsideTestReporter(t *testing.T) {
+	const allowed = "testReporter.fail"
+
+	sites := barePanicSites(t)
+	var offending []string
+	foundAllowed := false
+	for _, s := range sites {
+		if s.owner == allowed {
+			foundAllowed = true
+			continue
+		}
+		offending = append(offending, s.String())
+	}
+
+	// Self-check: if the scan stops seeing the one panic it must allow, it
+	// has broken and would pass vacuously.
+	require.True(t, foundAllowed,
+		"the source scan did not find the panic in %s; it has broken (or that panic moved)", allowed)
+	assert.Empty(t, offending,
+		"bare panic( in internal/mocks: route test-authoring errors through m.reporter "+
+			"(wrongReturnType or fail) so they fail the registered test instead of ending the test binary:\n%s",
+		strings.Join(offending, "\n"))
+}
+
+// panicSite is one call to the panic builtin and the declaration enclosing it.
+type panicSite struct {
+	pos   token.Position
+	owner string // "Recv.Method", "Func", or "package scope"
+}
+
+func (s panicSite) String() string {
+	return s.pos.String() + " in " + s.owner
+}
+
+// barePanicSites returns every panic(...) call in the package's non-test files.
+func barePanicSites(t *testing.T) []panicSite {
+	t.Helper()
+	entries, err := os.ReadDir(".")
+	require.NoError(t, err)
+	fset := token.NewFileSet()
+	var sites []panicSite
+	for _, e := range entries {
+		name := e.Name()
+		if e.IsDir() || !strings.HasSuffix(name, ".go") || strings.HasSuffix(name, "_test.go") {
+			continue
+		}
+		f, err := parser.ParseFile(fset, name, nil, 0)
+		require.NoError(t, err)
+		for _, decl := range f.Decls {
+			owner := declOwner(decl)
+			ast.Inspect(decl, func(n ast.Node) bool {
+				if isPanicCall(n) {
+					sites = append(sites, panicSite{pos: fset.Position(n.Pos()), owner: owner})
+				}
+				return true
+			})
+		}
+	}
+	return sites
+}
+
+func isPanicCall(n ast.Node) bool {
+	call, ok := n.(*ast.CallExpr)
+	if !ok {
+		return false
+	}
+	id, ok := call.Fun.(*ast.Ident)
+	return ok && id.Name == "panic"
+}
+
+// declOwner names a top-level declaration: "Recv.Method" for a method,
+// the function name for a function, "package scope" for anything else.
+func declOwner(decl ast.Decl) string {
+	fd, ok := decl.(*ast.FuncDecl)
+	if !ok {
+		return "package scope"
+	}
+	if fd.Recv == nil || len(fd.Recv.List) != 1 {
+		return fd.Name.Name
+	}
+	recv := fd.Recv.List[0].Type
+	if star, ok := recv.(*ast.StarExpr); ok {
+		recv = star.X
+	}
+	if id, ok := recv.(*ast.Ident); ok {
+		return id.Name + "." + fd.Name.Name
+	}
+	return fd.Name.Name
+}
diff --git a/internal/mocks/stores.go b/internal/mocks/stores.go
index ea6706bb..62ef53b2 100644
--- a/internal/mocks/stores.go
+++ b/internal/mocks/stores.go
@@ -959,7 +959,7 @@ func (m *MockConfigStore) GetMarketplaceListingAttempt(ctx context.Context, purc
 	if v := args.Get(0); v != nil {
 		a, ok := v.(*config.MarketplaceListingAttempt)
 		if !ok {
-			panic(fmt.Sprintf("mock: expected *config.MarketplaceListingAttempt, got %T", v))
+			m.reporter.wrongReturnType("GetMarketplaceListingAttempt", "*config.MarketplaceListingAttempt", v)
 		}
 		attempt = a
 	}
@@ -1010,7 +1010,7 @@ func (m *MockConfigStore) ListMarketplaceListingsToPoll(ctx context.Context) ([]
 	if v := args.Get(0); v != nil {
 		r, ok := v.([]config.PurchaseHistoryRecord)
 		if !ok {
-			panic(fmt.Sprintf("mock: expected []config.PurchaseHistoryRecord, got %T", v))
+			m.reporter.wrongReturnType("ListMarketplaceListingsToPoll", "[]config.PurchaseHistoryRecord", v)
 		}
 		rows = r
 	}
@@ -1813,7 +1813,7 @@ func (m *MockConfigStore) ListStoredRecommendationsChunk(ctx context.Context, fi
 	args := m.Called(ctx, filter, after, limit)
 	v, ok := args.Get(0).(config.RecommendationChunk)
 	if !ok {
-		panic(fmt.Sprintf("mock: expected config.RecommendationChunk, got %T", args.Get(0)))
+		m.reporter.wrongReturnType("ListStoredRecommendationsChunk", "config.RecommendationChunk", args.Get(0))
 	}
 	return v, args.Error(1)
 }
@@ -2094,7 +2094,7 @@ func (m *MockConfigStore) ListHistoryExecutionsPage(ctx context.Context, q confi
 	}
 	v, ok := args.Get(0).([]config.PurchaseExecution)
 	if !ok {
-		panic(fmt.Sprintf("mock: expected []config.PurchaseExecution, got %T", args.Get(0)))
+		m.reporter.wrongReturnType("ListHistoryExecutionsPage", "[]config.PurchaseExecution", args.Get(0))
 	}
 	return pageExecutionsLikeStore(v, &q), args.Error(1)
 }
@@ -2125,7 +2125,7 @@ func (m *MockConfigStore) ListPurchaseHistoryPage(ctx context.Context, filter co
 			v[i] = config.PurchaseHistoryPageRow{PurchaseHistoryRecord: rows[i], RowID: PurchaseHistoryFixtureRowID(i)}
 		}
 	default:
-		panic(fmt.Sprintf("mock: expected []config.PurchaseHistoryPageRow or []config.PurchaseHistoryRecord, got %T", args.Get(0)))
+		m.reporter.wrongReturnType("ListPurchaseHistoryPage", "[]config.PurchaseHistoryPageRow or []config.PurchaseHistoryRecord", args.Get(0))
 	}
 	out := make([]config.PurchaseHistoryPageRow, 0, len(v))
 	for i := range v {