diff --git a/extensions/feishu/src/dedup.ts b/extensions/feishu/src/dedup.ts
index 84e4eb663..3b544883c 100644
--- a/extensions/feishu/src/dedup.ts
+++ b/extensions/feishu/src/dedup.ts
@@ -15,7 +15,7 @@ function resolveStateDirFromEnv(env: NodeJS.ProcessEnv = process.env): string {
     return stateOverride;
   }
   if (env.VITEST || env.NODE_ENV === "test") {
-    return path.join(os.tmpdir(), `openclaw-vitest-${process.pid}`);
+    return path.join(os.tmpdir(), "openclaw-vitest-" + process.pid);
   }
   return path.join(os.homedir(), ".openclaw");
 }