Do a better job of not having the frontend lockup if the session doesn't exist

src/public/app/widgets/llm_chat/communication.ts

@@ -28,9 +28,9 @@ export async function createChatSession(): Promise<string | null> {
  */
 export async function checkSessionExists(sessionId: string): Promise<boolean> {
     try {
-        const sessionCheck = await server.get<any>(`llm/sessions/${sessionId}`);
+        const sessionCheck = await server.getWithSilentNotFound<any>(`llm/sessions/${sessionId}`);
         return !!(sessionCheck && sessionCheck.id);
-    } catch (error) {
+    } catch (error: any) {
         console.log(`Error checking session ${sessionId}:`, error);
         return false;
     }

src/public/app/widgets/llm_chat/llm_chat_panel.ts

@@ -328,7 +328,7 @@ export default class LlmChatPanel extends BasicWidget {
 
                             // If we successfully restored a session, also fetch the latest session data
                             try {
-                                const sessionData = await server.get<{
+                                const sessionData = await server.getWithSilentNotFound<{
                                     metadata?: {
                                         model?: string;
                                         provider?: string;
@@ -356,6 +356,7 @@ export default class LlmChatPanel extends BasicWidget {
                                         content?: string;
                                     }>;
                                 }>(`llm/sessions/${savedData.sessionId}`);
+
                                 if (sessionData && sessionData.metadata) {
                                     // Update our metadata with the latest from the server
                                     this.metadata = {
@@ -368,9 +369,18 @@ export default class LlmChatPanel extends BasicWidget {
                                     if (sessionData.sources && sessionData.sources.length > 0) {
                                         this.sources = sessionData.sources;
                                     }
+                                } else {
+                                    // Session data is missing or incomplete, create a new session
+                                    console.log(`Invalid or incomplete session data for ${savedData.sessionId}, creating a new session`);
+                                    this.sessionId = null;
+                                    await this.createChatSession();
                                 }
-                            } catch (fetchError) {
+                            } catch (fetchError: any) {
+                                // Handle fetch errors (this should now only happen for network issues, not 404s)
                                 console.warn(`Could not fetch latest session data: ${fetchError}`);
+                                console.log(`Creating a new session after fetch error`);
+                                this.sessionId = null;
+                                await this.createChatSession();
                             }
                         } else {
                             console.log(`Saved session ${savedData.sessionId} not found, will create new one`);

src/services/llm/rest_chat_service.ts

@@ -1604,7 +1604,15 @@ class RestChatService {
             // Check if session exists
             const session = sessions.get(sessionId);
             if (!session) {
-                throw new Error(`Session with ID ${sessionId} not found`);
+                // Instead of throwing an error, return a structured 404 response
+                // that the frontend can handle gracefully
+                res.status(404).json({
+                    error: true,
+                    message: `Session with ID ${sessionId} not found`,
+                    code: 'session_not_found',
+                    sessionId
+                });
+                return null; // Return null to prevent further processing
             }
 
             // Return session with metadata and additional fields