diff --git a/tools/build_trees.py b/tools/build_trees.py
index c5fbd67..9eab158 100644
--- a/tools/build_trees.py
+++ b/tools/build_trees.py
@@ -265,6 +265,10 @@ async def main_async(args: argparse.Namespace) -> None:
     assert videos_dir.is_dir(), f"视频目录不存在: {videos_dir}"
 
     api_concurrency = int(os.getenv("TREE_BUILD_API_CONCURRENCY", "16"))
+    if api_concurrency < 1:
+        raise ValueError(f"TREE_BUILD_API_CONCURRENCY 必须 >= 1，当前值: {api_concurrency}")
+    if args.video_concurrency < 1:
+        raise ValueError(f"--video-concurrency 必须 >= 1，当前值: {args.video_concurrency}")
 
     # Phase 1: 待建发现（progress + 完整性双重跳过）
     progress_path = Path(args.progress_path)