diff --git a/aider/io.py b/aider/io.py
index cbbbd944a..0967b0da7 100644
--- a/aider/io.py
+++ b/aider/io.py
@@ -478,8 +478,8 @@ class InputOutput:
             return
         FileHistory(self.input_history_file).append_string(inp)
         # Also add to the in-memory history if it exists
-        if hasattr(self, "session") and hasattr(self.session, "history"):
-            self.session.history.append_string(inp)
+        if self.prompt_session and self.prompt_session.history:
+            self.prompt_session.history.append_string(inp)
 
     def get_input_history(self):
         if not self.input_history_file: