fix: add agent preface before generation

app/(chat)/api/chat/route.ts

@@ -541,6 +541,65 @@ function writeCanvasOperationShadowChunk(params: {
   );
 }
 
+const AGENT_EXECUTION_PREFACE_INTERNAL_PATTERN =
+  /(?:^|\n)\s*(?:#{1,6}\s*)?(?:需求理解|图片分析|执行计划|输出设置|优化后提示词|使用建议)(?:\s|[:：]|$)|【\s*(?:需求理解|图片分析|执行计划|输出设置|优化后提示词|使用建议)\s*】|提示词|自动优化|模型|提交生成|回写|流程|步骤/;
+
+function buildAgentExecutionPrefaceText(params: {
+  friendlyMessage?: string | null;
+  fallback: string;
+}) {
+  const fallback = String(params.fallback || "").replace(/\s+/g, " ").trim();
+  const rawMessage = String(params.friendlyMessage || "")
+    .replace(/<!--[\s\S]*?-->/g, "")
+    .trim();
+
+  if (!rawMessage || AGENT_EXECUTION_PREFACE_INTERNAL_PATTERN.test(rawMessage)) {
+    return fallback;
+  }
+
+  const candidate = rawMessage
+    .split(/\r?\n/)
+    .map((line) => line.replace(/^[-*]\s*/, "").trim())
+    .find(Boolean);
+
+  if (!candidate || AGENT_EXECUTION_PREFACE_INTERNAL_PATTERN.test(candidate)) {
+    return fallback;
+  }
+
+  const firstSentence = candidate.match(/^(.{1,80}?[。！？!?~～])/u)?.[1] || candidate;
+  const compact = firstSentence.replace(/\s+/g, " ").trim().slice(0, 80);
+  return /[。！？!?~～]$/.test(compact) ? compact : `${compact}。`;
+}
+
+async function writeAgentExecutionPrefaceMessage(params: {
+  writer: StreamWriter;
+  chatId: string;
+  label: string;
+  friendlyMessage?: string | null;
+  fallback: string;
+}) {
+  const text = buildAgentExecutionPrefaceText({
+    friendlyMessage: params.friendlyMessage,
+    fallback: params.fallback,
+  });
+  if (!text) return null;
+
+  const messageId = generateUUID();
+  writeAssistantTextChunk(params.writer, text, params.label, messageId);
+
+  try {
+    await saveAssistantTextOnlyMessage({
+      chatId: params.chatId,
+      messageId,
+      text,
+    });
+  } catch (error) {
+    chatApiLogger.warn("[Chat API] Failed to persist agent execution preface:", error);
+  }
+
+  return messageId;
+}
+
 async function replayAssistantMessagesForDuplicateRequest({
   chatId,
   userMessageId,
@@ -7715,6 +7774,16 @@ export async function POST(request: Request) {
     ) {
       const directImageStream = createUIMessageStream({
         execute: async ({ writer }) => {
+          await writeAgentExecutionPrefaceMessage({
+            writer,
+            chatId: id,
+            label: "agent:generate_image:preface",
+            friendlyMessage: smartAutoFriendlyMessage,
+            fallback:
+              directAgentToolTargetImageUrls.length > 0
+                ? "收到，我会参考你选的图片来生成新画面，稍等一下。"
+                : "好的，我按你的描述来做一版画面，稍等我处理一下。",
+          });
           writeAgentProgressChunk(
             writer,
             buildDirectAgentImageContextProgress({
@@ -7917,6 +7986,16 @@ export async function POST(request: Request) {
     ) {
       const directVideoStream = createUIMessageStream({
         execute: async ({ writer }) => {
+          await writeAgentExecutionPrefaceMessage({
+            writer,
+            chatId: id,
+            label: "agent:generate_video:preface",
+            friendlyMessage: smartAutoFriendlyMessage,
+            fallback:
+              directAgentToolTargetImageUrls.length > 0
+                ? "收到，我会参考你选的画面来生成视频，稍等一下。"
+                : "好的，我按你的需求来做这段视频，稍等我处理一下。",
+          });
           const assistantMessageId = generateUUID();
           writeAgentProgressChunk(
             writer,
@@ -8123,6 +8202,13 @@ export async function POST(request: Request) {
       const directToolLabel = getDirectAgentToolLabel(directAgentToolCapability);
       const directToolStream = createUIMessageStream({
         execute: async ({ writer }) => {
+          await writeAgentExecutionPrefaceMessage({
+            writer,
+            chatId: id,
+            label: `agent:${directAgentToolCapability}:preface`,
+            friendlyMessage: smartAutoFriendlyMessage,
+            fallback: `好的，我来帮你${directToolLabel}，稍等我处理一下。`,
+          });
           writeAgentProgressChunk(
             writer,
             buildDirectAgentImageContextProgress({

components/canvas/CanvasChatPanel.tsx

@@ -12225,10 +12225,7 @@ export function CanvasChatPanel({
   const isAgentTargetClarificationActive =
     shouldShowAgentTargetLockCard && activeAgentTargetLock?.stage === "clarify";
   const shouldShowAgentProgressCard =
-    activeComposerMode === "agent" &&
-    Boolean(activeAgentProgress) &&
-    activeAgentProgress?.stage !== "completed" &&
-    activeAgentProgress?.stage !== "failed";
+    false;
   const agentTargetLockPreviewItems = useMemo(() => {
     if (!activeAgentTargetLock) return [] as AgentTargetLockRefPreview[];
     const targets = Array.isArray(activeAgentTargetLock.targets) ? activeAgentTargetLock.targets : [];