Implement unique filename generation to prevent overwriting existing session files

README.md

@@ -14,6 +14,8 @@ Custom OpenClaw session-memory hook.
 - Saves the **full** user/assistant session context into `workspace/memory/`
 - Uses `agents.defaults.userTimezone` for date/time formatting
 - Uses a slugged filename, with slug generation based on a small excerpt
+ - Avoids overwriting existing files: if a filename already exists the hook
+   appends `-1`, `-2`, ... to produce a unique filename.
 
 ## Disable the bundled hook
 
@@ -42,3 +44,8 @@ Or set it false in config:
 ## Notes
 
 This repo is intentionally lightweight, it exists so the custom hook can live in the managed hooks directory and stay separate from the bundled one.
+
+If you prefer atomic creation to fully eliminate a race window (two processes
+creating the same new filename simultaneously), replace the simple existence
+check with an atomic open/write using `fs.open(..., 'wx')` or write to a
+temporary file and `fs.rename()` it into place.