diff --git a/src/Netclaw.Actors/Tools/JsonReadTool.cs b/src/Netclaw.Actors/Tools/JsonReadTool.cs
index fe108948c..13f1289c5 100644
--- a/src/Netclaw.Actors/Tools/JsonReadTool.cs
+++ b/src/Netclaw.Actors/Tools/JsonReadTool.cs
@@ -190,9 +190,11 @@ private static bool TryParsePointer(string source, out JsonPointer pointer)
         }
 
         var tokens = new List<string>();
+        var token = new StringBuilder();
         foreach (var encodedToken in source[1..].Split('/'))
         {
-            var token = new StringBuilder(encodedToken.Length);
+            token.Clear();
+            token.EnsureCapacity(encodedToken.Length);
             for (var index = 0; index < encodedToken.Length; index++)
             {
                 if (encodedToken[index] != '~')