HOOK.md

@@ -17,6 +17,9 @@ metadata:
 Writes full user/assistant transcript context from the previous session into
 `<workspace>/memory/YYYY-MM-DD-slug.md` when `/new` or `/reset` runs.
 
+This hook avoids overwriting existing files by choosing a unique filename
+when a collision occurs (it appends `-1`, `-2`, etc. to the base name).
+
 Differences from bundled session-memory:
 
 - Uses full session context in output file

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.

handler.ts

@@ -197,6 +197,26 @@ function buildSlugExcerpt(full: string): string {
   return tail.slice(-3000);
 }
 
+async function getUniqueFilePath(dir: string, filename: string): Promise<string> {
+  const candidate = path.join(dir, filename);
+  try {
+    await fs.access(candidate);
+  } catch {
+    return candidate;
+  }
+
+  const parsed = path.parse(filename);
+  for (let i = 1; ; i += 1) {
+    const name = `${parsed.name}-${i}${parsed.ext}`;
+    const p = path.join(dir, name);
+    try {
+      await fs.access(p);
+    } catch {
+      return p;
+    }
+  }
+}
+
 async function generateSlug(params: {
   excerpt: string;
   cfg: AnyObj;
@@ -274,7 +294,7 @@ const handler = async (event: {
     await fs.mkdir(memoryDir, { recursive: true });
 
     const filename = `${dateStr}-${slug}.md`;
-    const memoryFilePath = path.join(memoryDir, filename);
+    const memoryFilePath = await getUniqueFilePath(memoryDir, filename);
 
     const source = typeof context.commandSource === "string" ? context.commandSource : "unknown";