diff --git a/src/OpenClaw.Shared/NotificationCategorizer.cs b/src/OpenClaw.Shared/NotificationCategorizer.cs
index 8559d69..e832638 100644
--- a/src/OpenClaw.Shared/NotificationCategorizer.cs
+++ b/src/OpenClaw.Shared/NotificationCategorizer.cs
@@ -87,29 +87,37 @@ public class NotificationCategorizer
     /// </summary>
     public static (string title, string type) ClassifyByKeywords(string text)
     {
-        var lower = text.ToLowerInvariant();
-        if (lower.Contains("blood sugar") || lower.Contains("glucose") ||
-            lower.Contains("cgm") || lower.Contains("mg/dl"))
+        // Use OrdinalIgnoreCase overloads to avoid allocating a lowercased copy of `text`.
+        if (text.Contains("blood sugar", StringComparison.OrdinalIgnoreCase) ||
+            text.Contains("glucose", StringComparison.OrdinalIgnoreCase) ||
+            text.Contains("cgm", StringComparison.OrdinalIgnoreCase) ||
+            text.Contains("mg/dl", StringComparison.OrdinalIgnoreCase))
             return ("🩸 Blood Sugar Alert", "health");
-        if (lower.Contains("urgent") || lower.Contains("critical") ||
-            lower.Contains("emergency"))
+        if (text.Contains("urgent", StringComparison.OrdinalIgnoreCase) ||
+            text.Contains("critical", StringComparison.OrdinalIgnoreCase) ||
+            text.Contains("emergency", StringComparison.OrdinalIgnoreCase))
             return ("🚨 Urgent Alert", "urgent");
-        if (lower.Contains("reminder"))
+        if (text.Contains("reminder", StringComparison.OrdinalIgnoreCase))
             return ("⏰ Reminder", "reminder");
-        if (lower.Contains("stock") || lower.Contains("in stock") ||
-            lower.Contains("available now"))
+        if (text.Contains("stock", StringComparison.OrdinalIgnoreCase) ||
+            text.Contains("in stock", StringComparison.OrdinalIgnoreCase) ||
+            text.Contains("available now", StringComparison.OrdinalIgnoreCase))
             return ("📦 Stock Alert", "stock");
-        if (lower.Contains("email") || lower.Contains("inbox") ||
-            lower.Contains("gmail"))
+        if (text.Contains("email", StringComparison.OrdinalIgnoreCase) ||
+            text.Contains("inbox", StringComparison.OrdinalIgnoreCase) ||
+            text.Contains("gmail", StringComparison.OrdinalIgnoreCase))
             return ("📧 Email", "email");
-        if (lower.Contains("calendar") || lower.Contains("meeting") ||
-            lower.Contains("event"))
+        if (text.Contains("calendar", StringComparison.OrdinalIgnoreCase) ||
+            text.Contains("meeting", StringComparison.OrdinalIgnoreCase) ||
+            text.Contains("event", StringComparison.OrdinalIgnoreCase))
             return ("📅 Calendar", "calendar");
-        if (lower.Contains("error") || lower.Contains("failed") ||
-            lower.Contains("exception"))
+        if (text.Contains("error", StringComparison.OrdinalIgnoreCase) ||
+            text.Contains("failed", StringComparison.OrdinalIgnoreCase) ||
+            text.Contains("exception", StringComparison.OrdinalIgnoreCase))
             return ("⚠️ Error", "error");
-        if (lower.Contains("build") || lower.Contains("ci ") ||
-            lower.Contains("deploy"))
+        if (text.Contains("build", StringComparison.OrdinalIgnoreCase) ||
+            text.Contains("ci ", StringComparison.OrdinalIgnoreCase) ||
+            text.Contains("deploy", StringComparison.OrdinalIgnoreCase))
             return ("🔨 Build", "build");
         return ("🤖 OpenClaw", "info");
     }
diff --git a/src/OpenClaw.Shared/OpenClawGatewayClient.cs b/src/OpenClaw.Shared/OpenClawGatewayClient.cs
index 0e21836..e044e90 100644
--- a/src/OpenClaw.Shared/OpenClawGatewayClient.cs
+++ b/src/OpenClaw.Shared/OpenClawGatewayClient.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Frozen;
 using System.Collections.Generic;
 using System.Text.Json;
 using System.Threading;
@@ -1569,23 +1570,25 @@ private static (string title, string type) ClassifyNotification(string text)
 
     // --- Utility ---
 
-    private static ActivityKind ClassifyTool(string toolName)
-    {
-        return toolName.ToLowerInvariant() switch
-        {
-            "exec" => ActivityKind.Exec,
-            "read" => ActivityKind.Read,
-            "write" => ActivityKind.Write,
-            "edit" => ActivityKind.Edit,
-            "web_search" => ActivityKind.Search,
-            "web_fetch" => ActivityKind.Search,
-            "browser" => ActivityKind.Browser,
-            "message" => ActivityKind.Message,
-            "tts" => ActivityKind.Tool,
-            "image" => ActivityKind.Tool,
-            _ => ActivityKind.Tool
-        };
-    }
+    // FrozenDictionary gives O(1) case-insensitive lookup without allocating a
+    // lowercased copy of toolName on every call.
+    private static readonly FrozenDictionary<string, ActivityKind> s_toolKindMap =
+        new Dictionary<string, ActivityKind>(StringComparer.OrdinalIgnoreCase)
+        {
+            ["exec"]       = ActivityKind.Exec,
+            ["read"]       = ActivityKind.Read,
+            ["write"]      = ActivityKind.Write,
+            ["edit"]       = ActivityKind.Edit,
+            ["web_search"] = ActivityKind.Search,
+            ["web_fetch"]  = ActivityKind.Search,
+            ["browser"]    = ActivityKind.Browser,
+            ["message"]    = ActivityKind.Message,
+            ["tts"]        = ActivityKind.Tool,
+            ["image"]      = ActivityKind.Tool,
+        }.ToFrozenDictionary(StringComparer.OrdinalIgnoreCase);
+
+    private static ActivityKind ClassifyTool(string toolName) =>
+        s_toolKindMap.TryGetValue(toolName, out var kind) ? kind : ActivityKind.Tool;
 
     private static string ShortenPath(string path)
     {