From 4f65e01a6372e4e28e8c3aeb70d9b1cee081ec9e Mon Sep 17 00:00:00 2001
From: Bohdan Triapitsyn <artmore@protonmail.com>
Date: Sun, 12 Jul 2026 00:45:26 +0300
Subject: [PATCH] fix(sync): defer incomplete assistant-only pages

---
 packages/ui/src/sync/use-sync.ts | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/packages/ui/src/sync/use-sync.ts b/packages/ui/src/sync/use-sync.ts
index 9abdd76b..9a50ad01 100644
--- a/packages/ui/src/sync/use-sync.ts
+++ b/packages/ui/src/sync/use-sync.ts
@@ -447,8 +447,9 @@ export function useSync() {
         // user sees content as soon as a user boundary appears, instead of
         // waiting for the full expansion sequence before the first paint.
         if (!options?.before && !page.complete && !hasUserMessage(page.session)) {
-          for (const nextLimit of getInitialPageExpansionLimits()) {
-            if (nextLimit <= limit) continue
+          const expansionLimits = getInitialPageExpansionLimits().filter((nextLimit) => nextLimit > limit)
+          for (let index = 0; index < expansionLimits.length; index += 1) {
+            const nextLimit = expansionLimits[index]
             if (options?.isStale?.()) {
               setMetaFor(sessionID, { loading: false })
               return
@@ -458,12 +459,22 @@ export function useSync() {
               setMetaFor(sessionID, { loading: false })
               return
             }
-            committed = commitMessagesToStore(expandedPage, options?.mode, options?.isStale)
+            const hasBoundary = hasUserMessage(expandedPage.session)
+            const isFinalExpansion = index === expansionLimits.length - 1
+            if (expandedPage.complete || hasBoundary || isFinalExpansion) {
+              committed = commitMessagesToStore(expandedPage, options?.mode, options?.isStale)
+            } else {
+              committed = {
+                messages: expandedPage.session,
+                cursor: expandedPage.cursor,
+                complete: expandedPage.complete,
+              }
+            }
             if (options?.isStale?.()) {
               setMetaFor(sessionID, { loading: false })
               return
             }
-            if (expandedPage.complete || hasUserMessage(expandedPage.session)) break
+            if (expandedPage.complete || hasBoundary) break
           }
         }