diff --git a/aider/main.py b/aider/main.py
index 58de4074e..e26ee895b 100644
--- a/aider/main.py
+++ b/aider/main.py
@@ -870,9 +870,10 @@ def main(argv=None, input=None, output=None, force_git_root=None, return_coder=F
     if args.aiderignore:
         ignores.append(args.aiderignore)
 
+    # if args.subtree_only, pass root=os.cwd ai!
     if args.watch_files:
         file_watcher = FileWatcher(
-            coder, gitignores=ignores, verbose=args.verbose, analytics=analytics
+            coder, gitignores=ignores, verbose=args.verbose, analytics=analytics,
         )
         coder.file_watcher = file_watcher