diff --git a/recline/repl/shell.py b/recline/repl/shell.py
index afd5992..47999cd 100644
--- a/recline/repl/shell.py
+++ b/recline/repl/shell.py
@@ -240,6 +240,7 @@ def track_command_history(filename: str) -> None:
         # default history len is -1 (infinite), which may grow unruly
         readline.set_history_length(1000)
     except IOError:
+        # Missing/unreadable history file is non-fatal (e.g., first run); continue.
         pass
     atexit.register(readline.write_history_file, filename)