diff --git a/apps/desktop/src/app/session/hooks/use-prompt-actions.ts b/apps/desktop/src/app/session/hooks/use-prompt-actions.ts
index 62d685fc7..e1e13b9d4 100644
--- a/apps/desktop/src/app/session/hooks/use-prompt-actions.ts
+++ b/apps/desktop/src/app/session/hooks/use-prompt-actions.ts
@@ -65,7 +65,7 @@ interface PromptActionsOptions {
   activeSessionIdRef: MutableRefObject<string | null>
   busyRef: MutableRefObject<boolean>
   branchCurrentSession: () => Promise<boolean>
-  createBackendSessionForSend: () => Promise<string | null>
+  createBackendSessionForSend: (preview?: string | null) => Promise<string | null>
   handleSkinCommand: (arg: string) => string
   requestGateway: <T>(method: string, params?: Record<string, unknown>) => Promise<T>
   selectedStoredSessionIdRef: MutableRefObject<string | null>
@@ -296,7 +296,7 @@ export function usePromptActions({
 
       if (!sessionId) {
         try {
-          sessionId = await createBackendSessionForSend()
+          sessionId = await createBackendSessionForSend(visibleText)
         } catch (err) {
           dropOptimistic(null)
           releaseBusy()
diff --git a/apps/desktop/src/app/session/hooks/use-session-actions.ts b/apps/desktop/src/app/session/hooks/use-session-actions.ts
index 7b301f7f3..a07bfdb64 100644
--- a/apps/desktop/src/app/session/hooks/use-session-actions.ts
+++ b/apps/desktop/src/app/session/hooks/use-session-actions.ts
@@ -303,7 +303,7 @@ export function useSessionActions({
     [activeSessionIdRef, busyRef, navigate, selectedStoredSessionIdRef]
   )
 
-  const createBackendSessionForSend = useCallback(async (): Promise<string | null> => {
+  const createBackendSessionForSend = useCallback(async (preview: string | null = null): Promise<string | null> => {
     const startingActiveSessionId = activeSessionIdRef.current
     const startingStoredSessionId = selectedStoredSessionIdRef.current
     const startingRouteToken = getRouteToken()
@@ -330,7 +330,11 @@ export function useSessionActions({
       ensureSessionState(created.session_id, stored)
 
       if (stored) {
-        upsertOptimisticSession(created, stored)
+        // Seed the sidebar preview with the user's first message so the row
+        // reads meaningfully while the turn is in flight, instead of flashing
+        // "Untitled session" until the turn persists and auto-title runs. The
+        // server later returns its own preview/title and supersedes this.
+        upsertOptimisticSession(created, stored, null, preview?.trim() || null)
         navigate(sessionRoute(stored), { replace: true })
       }