diff --git a/changelogs/fragments/10999.yml b/changelogs/fragments/10999.yml
new file mode 100644
index 000000000000..b7be5b0ba4fd
--- /dev/null
+++ b/changelogs/fragments/10999.yml
@@ -0,0 +1,2 @@
+fix:
+- [BUG][Chat] Unregister tools when component unmount ([#10999](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/10999))
\ No newline at end of file
diff --git a/src/plugins/chat/public/plugin.ts b/src/plugins/chat/public/plugin.ts
index 7d402faa6213..f63032d63aef 100644
--- a/src/plugins/chat/public/plugin.ts
+++ b/src/plugins/chat/public/plugin.ts
@@ -188,5 +188,6 @@ export class ChatPlugin implements Plugin<ChatPluginSetup, ChatPluginStart> {
   public stop() {
     this.paddingSizeSubscription?.unsubscribe();
     this.unsubscribeWindowStateChange?.();
+    this.chatService?.destroy();
   }
 }
diff --git a/src/plugins/chat/public/services/chat_service.ts b/src/plugins/chat/public/services/chat_service.ts
index 8dde65b5daa8..531b155840c3 100644
--- a/src/plugins/chat/public/services/chat_service.ts
+++ b/src/plugins/chat/public/services/chat_service.ts
@@ -3,10 +3,11 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import { Observable } from 'rxjs';
+import { Observable, Subscription } from 'rxjs';
 import { AgUiAgent } from './ag_ui_agent';
 import { RunAgentInput, Message, UserMessage, ToolMessage } from '../../common/types';
 import type { ToolDefinition } from '../../../context_provider/public';
+import { AssistantActionService } from '../../../context_provider/public';
 import { ChatLayoutMode } from '../components/chat_header_button';
 import type { ChatWindowInstance } from '../components/chat_window';
 import {
@@ -51,6 +52,9 @@ export class ChatService {
   // ChatWindow ref for delegating sendMessage calls to proper timeline management
   private chatWindowRef: React.RefObject<ChatWindowInstance> | null = null;
 
+  // Subscription to assistant action service for tool updates
+  private toolSubscription?: Subscription;
+
   constructor(
     uiSettings: IUiSettingsClient,
     coreChatService?: ChatServiceStart,
@@ -69,6 +73,12 @@ export class ChatService {
       this.coreChatService.setThreadId(currentChatState.threadId);
     }
     this.currentMessages = currentChatState?.messages || [];
+
+    // Subscribe to assistant action service to keep tools in sync
+    const assistantActionService = AssistantActionService.getInstance();
+    this.toolSubscription = assistantActionService.getState$().subscribe((state) => {
+      this.availableTools = state.toolDefinitions;
+    });
   }
 
   public getThreadId = () => {
@@ -514,4 +524,14 @@ export class ChatService {
     // Clear dynamic context from global store for fresh chat session
     this.clearDynamicContextFromStore();
   }
+
+  /**
+   * Cleanup method to properly dispose of subscriptions
+   */
+  public destroy(): void {
+    if (this.toolSubscription) {
+      this.toolSubscription.unsubscribe();
+      this.toolSubscription = undefined;
+    }
+  }
 }