diff --git a/ui/app/(prowler)/lighthouse/_components/chat/lighthouse-v2-chat-page.tsx b/ui/app/(prowler)/lighthouse/_components/chat/lighthouse-v2-chat-page.tsx
index adc018e165..7caf5ba727 100644
--- a/ui/app/(prowler)/lighthouse/_components/chat/lighthouse-v2-chat-page.tsx
+++ b/ui/app/(prowler)/lighthouse/_components/chat/lighthouse-v2-chat-page.tsx
@@ -22,7 +22,10 @@ import {
   buildOptimisticMessage,
   buildSessionTitle,
 } from "@/app/(prowler)/lighthouse/_lib/messages";
-import { notifyLighthouseV2SessionsChanged } from "@/app/(prowler)/lighthouse/_lib/session-events";
+import {
+  LIGHTHOUSE_V2_NEW_CHAT_EVENT,
+  notifyLighthouseV2SessionsChanged,
+} from "@/app/(prowler)/lighthouse/_lib/session-events";
 import { parseStreamEvent } from "@/app/(prowler)/lighthouse/_lib/stream-event-parser";
 import { buildLighthouseV2StreamUrl } from "@/app/(prowler)/lighthouse/_lib/stream-url";
 import {
@@ -305,6 +308,27 @@ export function LighthouseV2ChatPage({
     }
   });
 
+  // The sidebar "+" can't rely on routing to reset the latest conversation (its
+  // URL was set via replaceState, invisible to Next's router), so reset in place.
+  useMountEffect(() => {
+    const resetToNewChat = () => {
+      closeStream();
+      setActiveSessionId(null);
+      setMessages([]);
+      setInput("");
+      setFeedback(null);
+      setBlockedByConflict(false);
+      setIsSubmitting(false);
+      setLastSubmittedText(null);
+      setStreamState(createInitialLighthouseV2StreamState());
+      window.history.replaceState(null, "", "/lighthouse");
+    };
+
+    window.addEventListener(LIGHTHOUSE_V2_NEW_CHAT_EVENT, resetToNewChat);
+    return () =>
+      window.removeEventListener(LIGHTHOUSE_V2_NEW_CHAT_EVENT, resetToNewChat);
+  });
+
   const hasLiveAssistantActivity =
     Boolean(streamState.activeTaskId) ||
     Boolean(streamState.assistantText) ||
diff --git a/ui/app/(prowler)/lighthouse/_components/navigation/lighthouse-v2-sidebar-chat.tsx b/ui/app/(prowler)/lighthouse/_components/navigation/lighthouse-v2-sidebar-chat.tsx
index 15b0293fbc..ef44ec4c15 100644
--- a/ui/app/(prowler)/lighthouse/_components/navigation/lighthouse-v2-sidebar-chat.tsx
+++ b/ui/app/(prowler)/lighthouse/_components/navigation/lighthouse-v2-sidebar-chat.tsx
@@ -8,7 +8,10 @@ import {
   archiveLighthouseV2Session,
   getLighthouseV2Sessions,
 } from "@/app/(prowler)/lighthouse/_actions";
-import { LIGHTHOUSE_V2_SESSIONS_CHANGED_EVENT } from "@/app/(prowler)/lighthouse/_lib/session-events";
+import {
+  LIGHTHOUSE_V2_SESSIONS_CHANGED_EVENT,
+  notifyLighthouseV2NewChat,
+} from "@/app/(prowler)/lighthouse/_lib/session-events";
 import type { LighthouseV2Session } from "@/app/(prowler)/lighthouse/_types";
 import { Button } from "@/components/shadcn/button/button";
 import {
@@ -37,6 +40,8 @@ export function LighthouseV2SidebarChat({ isOpen }: { isOpen: boolean }) {
   };
 
   const handleNewSession = () => {
+    // Reset an already-open chat in place, then route (covers other pages too).
+    notifyLighthouseV2NewChat();
     router.push("/lighthouse");
   };
 
diff --git a/ui/app/(prowler)/lighthouse/_lib/session-events.ts b/ui/app/(prowler)/lighthouse/_lib/session-events.ts
index fabd378e9a..9f50b59762 100644
--- a/ui/app/(prowler)/lighthouse/_lib/session-events.ts
+++ b/ui/app/(prowler)/lighthouse/_lib/session-events.ts
@@ -5,3 +5,13 @@ export function notifyLighthouseV2SessionsChanged() {
   if (typeof window === "undefined") return;
   window.dispatchEvent(new Event(LIGHTHOUSE_V2_SESSIONS_CHANGED_EVENT));
 }
+
+export const LIGHTHOUSE_V2_NEW_CHAT_EVENT = "lighthouse-v2:new-chat";
+
+// Lets the sidebar reset an already-mounted chat page. router.push("/lighthouse")
+// is a no-op when the URL was set via replaceState (Next's router never saw it),
+// so the latest conversation needs a client-side reset signal.
+export function notifyLighthouseV2NewChat() {
+  if (typeof window === "undefined") return;
+  window.dispatchEvent(new Event(LIGHTHOUSE_V2_NEW_CHAT_EVENT));
+}