diff --git a/platform/internal/router/admin_test_token_route_test.go b/platform/internal/router/admin_test_token_route_test.go
new file mode 100644
index 00000000..bf288b35
--- /dev/null
+++ b/platform/internal/router/admin_test_token_route_test.go
@@ -0,0 +1,101 @@
+package router
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/DATA-DOG/go-sqlmock"
+	"github.com/Molecule-AI/molecule-monorepo/platform/internal/db"
+	"github.com/Molecule-AI/molecule-monorepo/platform/internal/handlers"
+	"github.com/Molecule-AI/molecule-monorepo/platform/internal/middleware"
+	"github.com/gin-gonic/gin"
+)
+
+// buildTestTokenEngine builds a minimal Gin engine containing only the
+// test-token route with AdminAuth middleware — the same registration that
+// router.go now uses. Allows us to verify the auth gate is enforced at the
+// HTTP layer without spinning up the full Setup() dependency graph.
+func buildTestTokenEngine(t *testing.T) gin.IRouter {
+	t.Helper()
+	gin.SetMode(gin.TestMode)
+	r := gin.New()
+	tokh := handlers.NewAdminTestTokenHandler()
+	r.GET("/admin/workspaces/:id/test-token", middleware.AdminAuth(db.DB), tokh.GetTestToken)
+	return r
+}
+
+// setupRouterTestDB initialises db.DB with a sqlmock connection and returns
+// the mock controller. Restores db.DB on test cleanup.
+func setupRouterTestDB(t *testing.T) sqlmock.Sqlmock {
+	t.Helper()
+	mockDB, mock, err := sqlmock.New()
+	if err != nil {
+		t.Fatalf("sqlmock.New: %v", err)
+	}
+	prev := db.DB
+	db.DB = mockDB
+	t.Cleanup(func() {
+		db.DB = prev
+		mockDB.Close()
+	})
+	return mock
+}
+
+// TestTestTokenRoute_RequiresAdminAuth_WhenTokensExist verifies that once the
+// platform has at least one live token, the test-token endpoint returns 401
+// for callers that provide no Authorization header. This is the core security
+// property added by the fix — without AdminAuth in the router the request
+// would reach the handler and mint a new bearer for any workspace UUID.
+func TestTestTokenRoute_RequiresAdminAuth_WhenTokensExist(t *testing.T) {
+	t.Setenv("MOLECULE_ENV", "development") // enable the handler itself
+	mock := setupRouterTestDB(t)
+
+	// HasAnyLiveTokenGlobal: platform has one enrolled workspace.
+	mock.ExpectQuery("SELECT COUNT.*FROM workspace_auth_tokens").
+		WillReturnRows(sqlmock.NewRows([]string{"count"}).AddRow(1))
+
+	r := buildTestTokenEngine(t)
+	w := httptest.NewRecorder()
+	req := httptest.NewRequest("GET", "/admin/workspaces/ws-target/test-token", nil)
+	// No Authorization header — should be rejected by AdminAuth.
+	r.(http.Handler).ServeHTTP(w, req)
+
+	if w.Code != http.StatusUnauthorized {
+		t.Errorf("expected 401 when tokens exist and no auth header, got %d: %s", w.Code, w.Body.String())
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("sqlmock expectations not met: %v", err)
+	}
+}
+
+// TestTestTokenRoute_FailOpenOnFreshInstall verifies that AdminAuth is
+// fail-open on a fresh install (HasAnyLiveTokenGlobal == 0), so the test-token
+// bootstrap path still works before the first workspace has registered.
+func TestTestTokenRoute_FailOpenOnFreshInstall(t *testing.T) {
+	t.Setenv("MOLECULE_ENV", "development")
+	mock := setupRouterTestDB(t)
+
+	// HasAnyLiveTokenGlobal: no tokens yet — fresh install.
+	mock.ExpectQuery("SELECT COUNT.*FROM workspace_auth_tokens").
+		WillReturnRows(sqlmock.NewRows([]string{"count"}).AddRow(0))
+
+	// Handler's own DB queries: workspace existence check + token insert.
+	mock.ExpectQuery("SELECT id FROM workspaces WHERE id =").
+		WithArgs("ws-bootstrap").
+		WillReturnRows(sqlmock.NewRows([]string{"id"}).AddRow("ws-bootstrap"))
+	mock.ExpectExec("INSERT INTO workspace_auth_tokens").
+		WillReturnResult(sqlmock.NewResult(0, 1))
+
+	r := buildTestTokenEngine(t)
+	w := httptest.NewRecorder()
+	req := httptest.NewRequest("GET", "/admin/workspaces/ws-bootstrap/test-token", nil)
+	r.(http.Handler).ServeHTTP(w, req)
+
+	if w.Code != http.StatusOK {
+		t.Errorf("expected 200 on fresh install (fail-open), got %d: %s", w.Code, w.Body.String())
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("sqlmock expectations not met: %v", err)
+	}
+}
diff --git a/platform/internal/router/router.go b/platform/internal/router/router.go
index 0b08d513..a2fbbf59 100644
--- a/platform/internal/router/router.go
+++ b/platform/internal/router/router.go
@@ -297,11 +297,13 @@ func Setup(hub *ws.Hub, broadcaster *events.Broadcaster, prov *provisioner.Provi
 	}
 
 	// Admin — test token minting (issue #6). Hidden in production via TestTokensEnabled().
-	// Registered at root (not inside AdminAuth) because it is itself the bootstrap for
-	// acquiring a token, and it's gated on MOLECULE_ENV / MOLECULE_ENABLE_TEST_TOKENS.
+	// AdminAuth is a second defence-in-depth layer: on a fresh install with no tokens yet,
+	// AdminAuth is fail-open (HasAnyLiveTokenGlobal == 0), so the bootstrap still works.
+	// Once any token exists, callers must present a valid bearer — unauthenticated workspace-
+	// UUID enumeration is blocked even on non-production instances.
 	{
 		tokh := handlers.NewAdminTestTokenHandler()
-		r.GET("/admin/workspaces/:id/test-token", tokh.GetTestToken)
+		r.GET("/admin/workspaces/:id/test-token", middleware.AdminAuth(db.DB), tokh.GetTestToken)
 	}
 
 	// Admin — GitHub App installation token refresh (issue #547).