diff --git a/app/api/evaluations/[id]/improve-prompt/route.ts b/app/api/evaluations/[id]/improve-prompt/route.ts
index ffbc2f1..ca9f4ce 100644
--- a/app/api/evaluations/[id]/improve-prompt/route.ts
+++ b/app/api/evaluations/[id]/improve-prompt/route.ts
@@ -30,19 +30,8 @@ export async function POST(
   try {
     const { id } = await params;
 
-    let userBody: Record<string, unknown> = {};
-    try {
-      const parsed = await request.json();
-      if (parsed && typeof parsed === "object") {
-        userBody = parsed as Record<string, unknown>;
-      }
-    } catch {
-      userBody = {};
-    }
-
     const payload = {
-      ...userBody,
-      callback_url: userBody.callback_url ?? resolveCallbackUrl(request),
+      callback_url: resolveCallbackUrl(request),
     };
 
     const { status, data } = await apiClient(
diff --git a/app/components/Sidebar.tsx b/app/components/Sidebar.tsx
index 6cc7d44..db58556 100644
--- a/app/components/Sidebar.tsx
+++ b/app/components/Sidebar.tsx
@@ -21,7 +21,9 @@ import {
   SlidersIcon,
   ChatIcon,
   ChartBarIcon,
+  WarningTriangleIcon,
 } from "@/app/components/icons";
+import { InfoTooltip } from "@/app/components/ui";
 import { MenuItem, SidebarProps } from "@/app/lib/types/nav";
 import { LoginModal } from "@/app/components/auth";
 import { Branding, UserMenuPopover } from "@/app/components/user-menu";
@@ -144,6 +146,7 @@ export default function Sidebar({
     submenu: item.submenu,
     gateDescription: item.gateDescription,
     featureFlag: item.featureFlag,
+    disabledReason: item.disabledReason,
   }));
 
   const getGateDescription = (name: string): string => {
@@ -182,7 +185,8 @@ export default function Sidebar({
           const hasSubmenu = item.submenu && item.submenu.length > 0;
           const isExpanded = expandedMenus[item.name];
           const isActive = activeRoute === item.route;
-          const gated = isItemGated(item);
+          const isDisabled = !!item.disabledReason;
+          const gated = !isDisabled && isItemGated(item);
 
           const hasActiveChild =
             hasSubmenu &&
@@ -194,8 +198,9 @@ export default function Sidebar({
             );
 
           return (
-            <div key={item.name}>
+            <div key={item.name} className="relative">
               <button
+                disabled={isDisabled}
                 onMouseEnter={(e) =>
                   gated && handleGateEnter(item.name, e.currentTarget)
                 }
@@ -208,13 +213,15 @@ export default function Sidebar({
                     router.push(item.route);
                   }
                 }}
-                className={`w-full text-left px-3 py-2 rounded-lg text-[14px] flex items-center gap-2.5 transition-all duration-150 border cursor-pointer ${
-                  isActive
-                    ? "bg-accent-primary/15 text-accent-primary font-semibold border-transparent"
-                    : hasActiveChild
-                      ? "bg-transparent text-accent-primary font-semibold border-transparent"
-                      : "bg-transparent text-text-secondary font-medium border-transparent hover:bg-neutral-100 hover:text-text-primary"
-                }`}
+                className={`w-full text-left px-3 py-2 rounded-lg text-[14px] flex items-center gap-2.5 transition-all duration-150 border ${
+                  isDisabled
+                    ? "bg-transparent text-text-secondary font-medium border-transparent opacity-50 cursor-not-allowed"
+                    : isActive
+                      ? "bg-accent-primary/15 text-accent-primary font-semibold border-transparent"
+                      : hasActiveChild
+                        ? "bg-transparent text-accent-primary font-semibold border-transparent"
+                        : "bg-transparent text-text-secondary font-medium border-transparent hover:bg-neutral-100 hover:text-text-primary"
+                } ${isDisabled ? "" : "cursor-pointer"}`}
               >
                 <span
                   className={
@@ -232,6 +239,16 @@ export default function Sidebar({
                   />
                 )}
               </button>
+              {isDisabled && (
+                <span className="absolute right-3 top-1/2 -translate-y-1/2">
+                  <InfoTooltip
+                    text={item.disabledReason}
+                    icon={
+                      <WarningTriangleIcon className="w-4 h-4 text-amber-500" />
+                    }
+                  />
+                </span>
+              )}
 
               {hasSubmenu && isExpanded && !gated && (
                 <div className="ml-5 mt-1 space-y-0.5 overflow-hidden border-l-2 border-border pl-3 animate-[slideDown_0.15s_ease-out]">
diff --git a/app/components/ui/InfoTooltip.tsx b/app/components/ui/InfoTooltip.tsx
index eeb711b..2b52bc4 100644
--- a/app/components/ui/InfoTooltip.tsx
+++ b/app/components/ui/InfoTooltip.tsx
@@ -12,9 +12,10 @@ import { TooltipIcon } from "@/app/components/icons";
 
 interface InfoTooltipProps {
   text: ReactNode;
+  icon?: ReactNode;
 }
 
-export default function InfoTooltip({ text }: InfoTooltipProps) {
+export default function InfoTooltip({ text, icon }: InfoTooltipProps) {
   const [visible, setVisible] = useState(false);
   const [positioned, setPositioned] = useState(false);
   const [position, setPosition] = useState({ top: 0, left: 0 });
@@ -65,7 +66,7 @@ export default function InfoTooltip({ text }: InfoTooltipProps) {
         onBlur={() => setVisible(false)}
         className="w-4 h-4 rounded-full text-[10px] font-bold flex items-center justify-center leading-none select-none cursor-pointer"
       >
-        <TooltipIcon className="w-4 h-4 text-[#99B3C1]" />
+        {icon ?? <TooltipIcon className="w-4 h-4 text-[#99B3C1]" />}
       </button>
       {visible &&
         createPortal(
diff --git a/app/lib/navConfig.ts b/app/lib/navConfig.ts
index 6ddad7d..6344257 100644
--- a/app/lib/navConfig.ts
+++ b/app/lib/navConfig.ts
@@ -38,6 +38,8 @@ export const NAV_ITEMS: NavItemConfig[] = [
     route: "/guardrails",
     icon: "shield",
     gateDescription: "Log in to manage guardrails and validators.",
+    disabledReason:
+      "Guardrails is temporarily disabled. We're making significant backend changes and things aren't in sync yet — it will be re-enabled once everything is aligned. To explore Guardrails, please contact the Kaapi team.",
   },
   {
     name: "Chat",
diff --git a/app/lib/types/nav.ts b/app/lib/types/nav.ts
index 4296f2d..76cd125 100644
--- a/app/lib/types/nav.ts
+++ b/app/lib/types/nav.ts
@@ -14,6 +14,7 @@ export interface NavItemConfig {
   gateDescription?: string;
   superuserOnly?: boolean;
   featureFlag?: FeatureFlagKey;
+  disabledReason?: string;
 }
 
 export interface SubMenuItem {
@@ -30,6 +31,7 @@ export interface MenuItem {
   submenu?: SubMenuItem[];
   gateDescription?: string;
   featureFlag?: FeatureFlagKey;
+  disabledReason?: string;
 }
 
 export interface SidebarProps {
diff --git a/middleware.ts b/middleware.ts
index cabf951..5f39062 100644
--- a/middleware.ts
+++ b/middleware.ts
@@ -21,6 +21,9 @@ const FEATURE_GATED_PREFIXES: Array<{
   flag: FeatureFlagKey;
 }> = [{ prefix: "/assessment", flag: FeatureFlag.ASSESSMENT }];
 
+// Temporarily disabled while backend changes are being synced; keep in sync with `disabledReason` in navConfig.
+const DISABLED_PREFIXES = ["/guardrails"];
+
 const GUEST_ONLY_ROUTES = new Set<string>(["/keystore"]);
 
 const HOME_ROUTE = "/chat";
@@ -57,6 +60,14 @@ export function middleware(request: NextRequest) {
   const isAuthenticated = hasApiKey || role === "superuser" || role === "user";
   const isSuperuser = role === "superuser";
 
+  if (
+    DISABLED_PREFIXES.some(
+      (prefix) => pathname === prefix || pathname.startsWith(`${prefix}/`),
+    )
+  ) {
+    return redirectHome(request);
+  }
+
   if (GUEST_ONLY_ROUTES.has(pathname)) {
     if (isAuthenticated) {
       return redirectHome(request);