diff --git a/ui/src/ui/app-render.ts b/ui/src/ui/app-render.ts
index 11bcacae1ee..376b0e4bc8d 100644
--- a/ui/src/ui/app-render.ts
+++ b/ui/src/ui/app-render.ts
@@ -1359,6 +1359,7 @@ export function renderApp(state: AppViewState) {
                 fallbackStatus: state.fallbackStatus,
                 assistantAvatarUrl: chatAvatarUrl,
                 messages: state.chatMessages,
+                historyTruncated: state.chatHistoryTruncated,
                 toolMessages: state.chatToolMessages,
                 streamSegments: state.chatStreamSegments,
                 stream: state.chatStream,
diff --git a/ui/src/ui/app.ts b/ui/src/ui/app.ts
index af0d0cb9c96..6d58f1b6d1d 100644
--- a/ui/src/ui/app.ts
+++ b/ui/src/ui/app.ts
@@ -159,6 +159,7 @@ export class OpenClawApp extends LitElement {
   @state() fallbackStatus: FallbackStatus | null = null;
   @state() chatAvatarUrl: string | null = null;
   @state() chatThinkingLevel: string | null = null;
+  @state() chatHistoryTruncated = false;
   @state() chatModelOverrides: Record<string, ChatModelOverride | null> = {};
   @state() chatModelsLoading = false;
   @state() chatModelCatalog: ModelCatalogEntry[] = [];
diff --git a/ui/src/ui/controllers/chat.ts b/ui/src/ui/controllers/chat.ts
index 138b83d3b81..c9026ed0efe 100644
--- a/ui/src/ui/controllers/chat.ts
+++ b/ui/src/ui/controllers/chat.ts
@@ -38,6 +38,7 @@ export type ChatState = {
   chatLoading: boolean;
   chatMessages: unknown[];
   chatThinkingLevel: string | null;
+  chatHistoryTruncated?: boolean;
   chatSending: boolean;
   chatMessage: string;
   chatAttachments: ChatAttachment[];
@@ -88,8 +89,10 @@ export async function loadChatHistory(state: ChatState) {
     state.chatStream = null;
     state.chatStreamStartedAt = null;
     state.chatMessages = filtered;
+    state.chatHistoryTruncated = filtered.length >= CHAT_HISTORY_REQUEST_LIMIT;
   } catch (err) {
     state.lastError = String(err);
+    state.chatHistoryTruncated = false;
   } finally {
     state.chatLoading = false;
   }
diff --git a/ui/src/ui/views/chat.ts b/ui/src/ui/views/chat.ts
index 077b3c3bd87..310b3fb1fc4 100644
--- a/ui/src/ui/views/chat.ts
+++ b/ui/src/ui/views/chat.ts
@@ -63,6 +63,8 @@ export type ChatProps = {
   compactionStatus?: CompactionIndicatorStatus | null;
   fallbackStatus?: FallbackIndicatorStatus | null;
   messages: unknown[];
+  /** True when history was limited by request limit (older messages not loaded). */
+  historyTruncated?: boolean;
   toolMessages: unknown[];
   streamSegments: Array<{ text: string; ts: number }>;
   stream: string | null;
@@ -1383,13 +1385,21 @@ function buildChatItems(props: ChatProps): Array<ChatItem | MessageGroup> {
   const history = Array.isArray(props.messages) ? props.messages : [];
   const tools = Array.isArray(props.toolMessages) ? props.toolMessages : [];
   const historyStart = Math.max(0, history.length - CHAT_HISTORY_RENDER_LIMIT);
-  if (historyStart > 0) {
+  const showTruncationNotice =
+    historyStart > 0 ||
+    (Boolean(props.historyTruncated) && history.length >= CHAT_HISTORY_RENDER_LIMIT);
+  if (showTruncationNotice) {
+    const hiddenCount = historyStart > 0 ? historyStart : "older";
+    const label =
+      typeof hiddenCount === "number"
+        ? `Showing last ${CHAT_HISTORY_RENDER_LIMIT} messages (${hiddenCount} hidden).`
+        : `Showing last ${CHAT_HISTORY_RENDER_LIMIT} messages (older messages not loaded).`;
     items.push({
       kind: "message",
       key: "chat:history:notice",
       message: {
         role: "system",
-        content: `Showing last ${CHAT_HISTORY_RENDER_LIMIT} messages (${historyStart} hidden).`,
+        content: label,
         timestamp: Date.now(),
       },
     });