diff --git a/packages/ui/src/App.tsx b/packages/ui/src/App.tsx
index 65dc973..d837ce1 100644
--- a/packages/ui/src/App.tsx
+++ b/packages/ui/src/App.tsx
@@ -45,6 +45,7 @@ import {
   clearActiveParentSession,
   createSession,
   fetchSessions,
+  flushSessionPersistence,
   updateSessionAgent,
   updateSessionModel,
 } from "./stores/sessions"
@@ -245,6 +246,12 @@ const App: Component = () => {
       return
     }
 
+    try {
+      await flushSessionPersistence(instanceId)
+    } catch (error) {
+      log.error("Failed to flush session persistence before closing", error)
+    }
+
     clearActiveParentSession(instanceId)
 
     try {
diff --git a/packages/ui/src/stores/session-state.ts b/packages/ui/src/stores/session-state.ts
index 17657c4..6d243c4 100644
--- a/packages/ui/src/stores/session-state.ts
+++ b/packages/ui/src/stores/session-state.ts
@@ -171,6 +171,15 @@ function schedulePersist(instanceId: string) {
   persistTimers.set(instanceId, timer)
 }
 
+async function flushSessionPersistence(instanceId: string) {
+  const existing = persistTimers.get(instanceId)
+  if (existing) {
+    clearTimeout(existing)
+    persistTimers.delete(instanceId)
+  }
+  await persistSessionTasks(instanceId)
+}
+
 async function persistSessionTasks(instanceId: string) {
   try {
     const instanceSessions = sessions().get(instanceId)
@@ -439,6 +448,7 @@ export {
   pruneDraftPrompts,
   withSession,
   persistSessionTasks,
+  flushSessionPersistence,
   setSessionCompactionState,
   setSessionPendingPermission,
   setActiveSession,