diff --git a/frontend/src/components/ui-new/containers/SessionChatBoxContainer.tsx b/frontend/src/components/ui-new/containers/SessionChatBoxContainer.tsx
index 60d99e0d..1d705994 100644
--- a/frontend/src/components/ui-new/containers/SessionChatBoxContainer.tsx
+++ b/frontend/src/components/ui-new/containers/SessionChatBoxContainer.tsx
@@ -6,6 +6,7 @@ import {
   type BaseCodingAgent,
 } from 'shared/types';
 import { useAttemptExecution } from '@/hooks/useAttemptExecution';
+import { useExecutionProcesses } from '@/hooks/useExecutionProcesses';
 import { useUserSystem } from '@/components/ConfigProvider';
 import { useApprovalFeedbackOptional } from '@/contexts/ApprovalFeedbackContext';
 import { useMessageEditContext } from '@/contexts/MessageEditContext';
@@ -176,21 +177,23 @@ export function SessionChatBoxContainer({
   // User profiles, config preference, and latest executor from processes
   const { profiles, config } = useUserSystem();
 
-  // Get last used executor from the most recently used session in this workspace
-  const lastSessionExecutor = useMemo(() => {
-    if (!sessions?.length) return null;
-    // Sessions are sorted by most recently used (first is most recent)
-    const mostRecentSession = sessions[0];
-    return mostRecentSession?.executor ?? null;
-  }, [sessions]);
+  // Fetch processes from last session to get full profile (only in new session mode)
+  const lastSessionId = isNewSessionMode ? sessions?.[0]?.id : undefined;
+  const { executionProcesses: lastSessionProcesses } =
+    useExecutionProcesses(lastSessionId);
 
-  // Compute latestProfileId: from processes, or fall back to last session's executor
+  // Compute latestProfileId: current processes > last session processes > session metadata
   const latestProfileId = useMemo(() => {
-    // If we have processes (existing session), use them
+    // Current session's processes take priority
     const fromProcesses = getLatestProfileFromProcesses(processes);
     if (fromProcesses) return fromProcesses;
 
-    // Fall back to last session's executor (useful for new session mode)
+    // Try full profile from last session's processes (includes variant)
+    const fromLastSession = getLatestProfileFromProcesses(lastSessionProcesses);
+    if (fromLastSession) return fromLastSession;
+
+    // Fallback: just executor from session metadata, no variant
+    const lastSessionExecutor = sessions?.[0]?.executor;
     if (lastSessionExecutor) {
       return {
         executor: lastSessionExecutor as BaseCodingAgent,
@@ -199,7 +202,7 @@ export function SessionChatBoxContainer({
     }
 
     return null;
-  }, [processes, lastSessionExecutor]);
+  }, [processes, lastSessionProcesses, sessions]);
 
   // Message editor state
   const {