diff --git a/aider/commands.py b/aider/commands.py
index 301029ca3..79a186b2a 100644
--- a/aider/commands.py
+++ b/aider/commands.py
@@ -139,7 +139,7 @@ class Commands:
     # any method called cmd_xxx becomes a command automatically.
     # each one must take an args param.
 
-    def cmd_commit(self, args):
+    def cmd_commit(self, args=None):
         "Commit edits to the repo made outside the chat (commit message optional)"
 
         if not self.coder.repo:
@@ -150,7 +150,7 @@ class Commands:
             self.io.tool_error("No more changes to commit.")
             return
 
-        commit_message = args.strip()
+        commit_message = args.strip() if args else None
         self.coder.repo.commit(message=commit_message)
 
     def cmd_lint(self, args="", fnames=None):