diff --git a/cameleer3-server-app/src/main/java/com/cameleer3/server/app/controller/EnvironmentAdminController.java b/cameleer3-server-app/src/main/java/com/cameleer3/server/app/controller/EnvironmentAdminController.java
index fb36c4cf..f558435a 100644
--- a/cameleer3-server-app/src/main/java/com/cameleer3/server/app/controller/EnvironmentAdminController.java
+++ b/cameleer3-server-app/src/main/java/com/cameleer3/server/app/controller/EnvironmentAdminController.java
@@ -27,6 +27,7 @@ public class EnvironmentAdminController {
 
     @GetMapping
     @Operation(summary = "List all environments")
+    @PreAuthorize("isAuthenticated()")
     public ResponseEntity<List<Environment>> listEnvironments() {
         return ResponseEntity.ok(environmentService.listAll());
     }
diff --git a/ui/src/components/LayoutShell.tsx b/ui/src/components/LayoutShell.tsx
index b5dfca2b..44b8761f 100644
--- a/ui/src/components/LayoutShell.tsx
+++ b/ui/src/components/LayoutShell.tsx
@@ -25,6 +25,7 @@ import { useRouteCatalog } from '../api/queries/catalog';
 import { useAgents } from '../api/queries/agents';
 import { useSearchExecutions, useAttributeKeys } from '../api/queries/executions';
 import { useUsers, useGroups, useRoles } from '../api/queries/admin/rbac';
+import { useEnvironments } from '../api/queries/admin/environments';
 import type { UserDetail, GroupDetail, RoleDetail } from '../api/queries/admin/rbac';
 import { useAuthStore, useIsAdmin } from '../auth/auth-store';
 import { useEnvironmentStore } from '../api/environment-store';
@@ -291,16 +292,20 @@ function LayoutContent() {
   const { data: allAgents } = useAgents();  // unfiltered — for environment discovery
   const { data: agents } = useAgents(undefined, undefined, selectedEnv);  // filtered — for sidebar/search
   const { data: attributeKeys } = useAttributeKeys();
+  const { data: envRecords = [] } = useEnvironments();
 
-  // Extract distinct environments from ALL agents (not filtered by selected env)
+  // Merge environments from both the environments table and agent heartbeats
   const environments: string[] = useMemo(() => {
-    if (!allAgents) return ['default'];
     const envSet = new Set<string>();
-    for (const a of allAgents as any[]) {
-      envSet.add(a.environmentId || 'default');
+    for (const e of envRecords) envSet.add(e.slug);
+    if (allAgents) {
+      for (const a of allAgents as any[]) {
+        envSet.add(a.environmentId || 'default');
+      }
     }
+    if (envSet.size === 0) envSet.add('default');
     return [...envSet].sort();
-  }, [allAgents]);
+  }, [allAgents, envRecords]);
 
   // --- Admin search data (only fetched on admin pages) ----------------
   const isAdminPage = location.pathname.startsWith('/admin');