diff --git a/aider/coders/base_coder.py b/aider/coders/base_coder.py
index abf5b865c..8e7814372 100755
--- a/aider/coders/base_coder.py
+++ b/aider/coders/base_coder.py
@@ -248,7 +248,7 @@ class Coder:
 
         for fname in self.abs_read_only_fnames:
             rel_fname = self.get_rel_fname(fname)
-            lines.append(f"Added {rel_fname} to the chat (read-only)")
+            lines.append(f"Added {rel_fname} to the chat (read-only).")
 
         if self.done_messages:
             lines.append("Restored previous conversation history.")