fix(dashboard): load all messages in chat on initial open (useChat + useQuickChat)

Both useChat (full ChatView) and useQuickChat (FAB) loaded only the first 50
messages on open and never paginated further. In useChat, loadMoreMessages
exists but ChatView never calls it — dead code. In useQuickChat, there was
no pagination at all.

Fix: add fetchAllMessagesInChat / fetchAllMessages helpers (paginate through
the API 200-msg cap), replace all limit:50 initial-load call sites, and
add stale-session guards via activeSessionRef before calling setMessages.
hasMoreMessages is set to false after a full initial load.

Forward-pagination path in useChat (isPaginationRequest=true) is preserved
for backward compat.

.changeset/fix-chat-view-message-truncation.md

@@ -0,0 +1,15 @@
+---
+"@runfusion/fusion": patch
+---
+
+Fix `useChat` truncating sessions longer than 50 messages on initial open.
+
+`loadMessages()` fetched `{ limit: 50 }` for the initial load. The
+`loadMoreMessages` callback was never called from `ChatView` (no scroll
+sentinel exists), so sessions beyond 50 messages were permanently cut off.
+
+Fix: introduce `fetchAllMessagesInChat()` that paginates through the API's
+200-message cap and replace the initial load path. A stale-session guard
+(via `activeSessionRef`) prevents overwriting a switched session's messages.
+The forward-pagination path (`isPaginationRequest = true`) is preserved
+unchanged for backward compatibility.

packages/dashboard/app/hooks/useChat.ts

@@ -239,6 +239,26 @@ function mapChatMessageToInfo(message: ChatMessage): ChatMessageInfo {
   };
 }
 
+/**
+ * Fetch all messages for a session, paginating through the API's 200-message cap.
+ * Used for the initial full load so sessions with >50 messages are never truncated.
+ */
+async function fetchAllMessagesInChat(
+  sessionId: string,
+  projectId: string | undefined,
+): Promise<ChatMessageInfo[]> {
+  const PAGE = 200;
+  const all: ChatMessageInfo[] = [];
+  let offset = 0;
+  for (;;) {
+    const data = await fetchChatMessages(sessionId, { limit: PAGE, offset }, projectId);
+    all.push(...data.messages.map(mapChatMessageToInfo));
+    if (data.messages.length < PAGE) break;
+    offset += PAGE;
+  }
+  return all;
+}
+
 export function useChat(
   projectId?: string,
   addToast?: (msg: string, type?: "success" | "error" | "warning") => void,
@@ -451,18 +471,23 @@ export function useChat(
       }
 
       try {
-        const data = await fetchChatMessages(sessionId, { limit: 50, ...opts }, projectId);
-        const mappedMessages = data.messages.map(mapChatMessageToInfo);
         if (isPaginationRequest) {
-          // Prepend older messages
+          // Prepend older messages (forward pagination, used when hasMoreMessages)
+          const data = await fetchChatMessages(sessionId, { limit: 50, ...opts }, projectId);
+          const mappedMessages = data.messages.map(mapChatMessageToInfo);
           setMessages((prev) => [...mappedMessages, ...prev]);
+          setHasMoreMessages(data.messages.length >= 50);
         } else {
-          setMessages(mappedMessages);
+          // Initial full load — fetch all messages, never truncate at 50
-          if (cacheKey) {
+          const allMessages = await fetchAllMessagesInChat(sessionId, projectId);
-            writeCache(cacheKey, mappedMessages, { maxBytes: 500_000 });
+          if (activeSessionRef.current?.id === sessionId) {
+            setMessages(allMessages);
+            if (cacheKey) {
+              writeCache(cacheKey, allMessages, { maxBytes: 500_000 });
+            }
+            setHasMoreMessages(false); // all messages loaded — inside guard
           }
         }
-        setHasMoreMessages(data.messages.length >= 50);
       } catch {
         if (!isPaginationRequest && messagesRef.current.length === 0 && hasCachedMessages) {
           setMessages(cachedMessages);

packages/dashboard/app/hooks/useQuickChat.ts

@@ -183,6 +183,22 @@ function mapChatMessageToInfo(message: ChatMessage): ChatMessageInfo {
   };
 }
 
+/**
+ * Fetch all messages for a session, paginating through the API's 200-message cap.
+ * Replaces the former hardcoded `limit: 50` that silently truncated long sessions.
+ */
+async function fetchAllMessages(sessionId: string, projectId?: string): Promise<ChatMessageInfo[]> {
+  const PAGE = 200; // API hard cap (Math.min(limit, 200))
+  const all: ChatMessageInfo[] = [];
+  let offset = 0;
+  for (;;) {
+    const data = await fetchChatMessages(sessionId, { limit: PAGE, offset }, projectId);
+    all.push(...data.messages.map(mapChatMessageToInfo));
+    if (data.messages.length < PAGE) break;
+    offset += PAGE;
+  }
+  return all;
+}
 /**
  * Hook for the QuickChatFAB component.
  * Provides chat session management and SSE streaming for real-time AI responses.
@@ -330,8 +346,8 @@ export function useQuickChat(
         isStreamingRef.current = false;
         streamRef.current = null;
         lastAttachedGenerationRef.current = null;
-        void fetchChatMessages(sessionId, { limit: 50 }, projectId).then((data) => {
+        void fetchAllMessages(sessionId, projectId).then((msgs) => {
-          setMessages(data.messages.map(mapChatMessageToInfo));
+          if (activeSessionRef.current?.id === sessionId) setMessages(msgs);
         }).catch(() => {});
         flushPendingMessage();
       },
@@ -347,8 +363,8 @@ export function useQuickChat(
         if (!options?.silent) {
           addToast?.(errorMessage, "error");
         }
-        void fetchChatMessages(sessionId, { limit: 50 }, projectId).then((resp) => {
+        void fetchAllMessages(sessionId, projectId).then((msgs) => {
-          setMessages(resp.messages.map(mapChatMessageToInfo));
+          if (activeSessionRef.current?.id === sessionId) setMessages(msgs);
         }).catch(() => {});
         flushPendingMessage();
       },
@@ -427,8 +443,9 @@ export function useQuickChat(
 
     setMessagesLoading(true);
     try {
-      const data = await fetchChatMessages(activeSession.id, { limit: 50 }, projectId);
+      const sessionId = activeSession.id;
-      setMessages(data.messages.map(mapChatMessageToInfo));
+      const msgs = await fetchAllMessages(sessionId, projectId);
+      if (activeSessionRef.current?.id === sessionId) setMessages(msgs);
     } catch (err) {
       console.error("[useQuickChat] Failed to load messages:", err);
     } finally {
@@ -471,8 +488,9 @@ export function useQuickChat(
         if (!data.session.isGenerating) {
           clearInterval(interval);
           // Reload messages to pick up the completed assistant message
-          const msgData = await fetchChatMessages(activeSession.id, { limit: 50 }, projectId);
+          const sessionId = activeSession.id;
-          setMessages(msgData.messages.map(mapChatMessageToInfo));
+          const msgs = await fetchAllMessages(sessionId, projectId);
+          if (activeSessionRef.current?.id === sessionId) setMessages(msgs);
           setStreamingText("");
           setStreamingThinking("");
           setStreamingToolCalls([]);
@@ -493,8 +511,9 @@ export function useQuickChat(
     if (!activeSession) return;
     setMessagesLoading(true);
     try {
-      const data = await fetchChatMessages(activeSession.id, { limit: 50 }, projectId);
+      const sessionId = activeSession.id;
-      setMessages(data.messages.map(mapChatMessageToInfo));
+      const msgs = await fetchAllMessages(sessionId, projectId);
+      if (activeSessionRef.current?.id === sessionId) setMessages(msgs);
     } catch (err) {
       console.error("[useQuickChat] Failed to reload messages:", err);
     } finally {