diff --git a/aider/coders/base_coder.py b/aider/coders/base_coder.py
index 3926cd987..c9e1e797c 100755
--- a/aider/coders/base_coder.py
+++ b/aider/coders/base_coder.py
@@ -771,6 +771,7 @@ class Coder:
         self.lint_outcome = None
         self.test_outcome = None
         self.shell_commands = []
+        self.message_cost = 0
 
         if self.repo:
             self.commit_before_message.append(self.repo.get_head_commit_sha())