diff --git a/apps/api/app/api/routes/scripts_ai.py b/apps/api/app/api/routes/scripts_ai.py
index 5ecb3f5d0..4b80b0840 100644
--- a/apps/api/app/api/routes/scripts_ai.py
+++ b/apps/api/app/api/routes/scripts_ai.py
@@ -356,7 +356,7 @@ def _fetch_ttwid():
     # 方式一：直接调 ttwid 注册接口
     try:
         with httpx.Client(timeout=8, follow_redirects=True, verify=False) as http:
-            http.post(
+            r = http.post(
                 "https://ttwid.bytedance.com/ttwid/union/register/",
                 json={
                     "region": "cn",
@@ -769,7 +769,7 @@ def _ytdlp_download_and_local_asr(page_url, temp_dir, cookiefile=None):
         cookie_files_to_try.append(cookiefile)
 
     # 2. 合成 cookie 重试（复用 _ytdlp_extract 的 cookie 生成逻辑，8次重试）
-    import time as _time
+    import secrets, time as _time
     ttwid = _fetch_ttwid()
     for i in range(8):
         if i % 3 == 0:
@@ -945,10 +945,9 @@ def _html_scrape_direct_url(page_url, timeout=15):
 @router.get("/douyin/__debug_diag")
 def douyin_diag():
     """[Staging only] 容器内网络/yt-dlp诊断"""
-    import tempfile as _tf
-    import time as _t
-
     import httpx as _httpx
+    import time as _t
+    import tempfile as _tf
     import yt_dlp as _ytdlp
 
     results = {}
@@ -1149,9 +1148,11 @@ def extract_from_douyin(
     # 整体重试：外层最多 2 轮完整链路，应对第三方 API 瞬时限流/CDN 抖动
     max_rounds = 2
     meta_duration = 0.0
+    last_err_stage = "unknown"  # 记录失败阶段，用于返回具体错误信息
     for round_idx in range(max_rounds):
         # 路径 A0 已成功则跳过 A1/A2/A3；否则走兜底链路
         if not direct_url:
+            last_err_stage = "parse"
             # 路径 A1：第三方解析 API（apizero 付费时可用）
             logger.info("抖音解析第%d轮开始: url=%s a0_ok=%s", round_idx + 1, page_url, bool(direct_url))
             try:
@@ -1187,6 +1188,7 @@ def extract_from_douyin(
 
         # 路径 B1：直链 → MediaKit 云端 ASR（最快，不下载视频）
         if direct_url and mk_client.is_available:
+            last_err_stage = "asr"
             try:
                 task_id = mk_client.asr_submit(direct_url)
                 text, mk_duration = mk_client.asr_poll(task_id)
@@ -1203,15 +1205,20 @@ def extract_from_douyin(
 
         # 路径 B2：回退下载 + 本地 ASR
         if not text:
+            last_err_stage = "download" if not direct_url else "asr"
             _dbg("fallback", f"download+local_asr round={round_idx+1}")
             try:
                 with tempfile.TemporaryDirectory(prefix="douyin_extract_") as temp_dir:
                     if direct_url:
                         _dbg("fallback_via", "direct_url_download")
+                        last_err_stage = "download"
                         text, dl_duration = _direct_url_download_and_local_asr(
                             direct_url, page_url, temp_dir
                         )
+                        if text:
+                            last_err_stage = "asr"  # 下载成功后才是asr阶段
                     else:
+                        last_err_stage = "parse"
                         text, dl_duration = _ytdlp_download_and_local_asr(
                             page_url, temp_dir, cookiefile=cookiefile
                         )
@@ -1264,10 +1271,17 @@ def extract_from_douyin(
             text = feed_desc.strip()
             logger.info("抖音所有 ASR 路径均失败，最终使用 Feed desc 作为文案: desc_len=%d", len(text))
         else:
-            logger.warning("抖音文案提取全部失败: url=%s", page_url)
+            # 根据失败阶段返回具体错误信息
+            stage_msg = {
+                "parse": "抖音视频链接解析失败，请检查链接是否正确或稍后重试",
+                "download": "抖音视频下载失败，请检查网络或稍后重试",
+                "asr": "抖音语音识别失败，请稍后重试或手动输入文案",
+            }
+            user_msg = stage_msg.get(last_err_stage, "抖音链接解析暂时不可用，请稍后重试或手动输入文案")
+            logger.warning("抖音文案提取全部失败: url=%s stage=%s", page_url, last_err_stage)
             raise HTTPException(
                 status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
-                detail="抖音链接解析暂时不可用，请稍后重试或手动输入文案",
+                detail=user_msg,
             )
 
     return ExtractFromDouyinResponse(