[Repo Assist] refactor: eliminate inline JsonSerializerOptions allocations in Shared and SetupEngine

src/OpenClaw.SetupEngine/Program.cs

@@ -191,7 +191,7 @@ public static async Task<int> Main(string[] args)
                 logPath = config.LogPath,
                 journalPath
             };
-            var json = System.Text.Json.JsonSerializer.Serialize(jsonResult, new System.Text.Json.JsonSerializerOptions { WriteIndented = true });
+        var json = System.Text.Json.JsonSerializer.Serialize(jsonResult, SetupConfig.JsonWriteOptions);
             await AtomicFile.WriteAllTextAsync(jsonOutput, json);
         }
 

src/OpenClaw.SetupEngine/SetupContext.cs

@@ -71,6 +71,15 @@ public SetupConfig ApplyUiDefaults(bool rollbackOnFailure = true)
         DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
         WriteIndented = true
     };
+
+    /// <summary>
+    /// Minimal write-only options for producing human-readable JSON files.
+    /// Shared to avoid repeated heap allocation at call sites.
+    /// </summary>
+    internal static readonly JsonSerializerOptions JsonWriteOptions = new()
+    {
+        WriteIndented = true
+    };
 }
 
 // ─── WSL Configuration ───
@@ -220,7 +229,7 @@ public void MergeIntoSettingsFile(string settingsPath)
             settings.TryAdd(kvp.Key, kvp.Value);
 
         Directory.CreateDirectory(Path.GetDirectoryName(settingsPath)!);
-        var json = JsonSerializer.Serialize(settings, new JsonSerializerOptions { WriteIndented = true });
+        var json = JsonSerializer.Serialize(settings, SetupConfig.JsonWriteOptions);
         AtomicFile.WriteAllText(settingsPath, json);
     }
 }

src/OpenClaw.SetupEngine/SetupSteps.cs

@@ -2213,7 +2213,7 @@ private static async Task WriteSetupStateAsync(SetupContext ctx, CancellationTok
             History = Array.Empty<object>()
         };
 
-        var json = System.Text.Json.JsonSerializer.Serialize(state, new System.Text.Json.JsonSerializerOptions { WriteIndented = true });
+        var json = System.Text.Json.JsonSerializer.Serialize(state, SetupConfig.JsonWriteOptions);
         await AtomicFile.WriteAllTextAsync(statePath, json, ct);
         ctx.Logger.Info($"Wrote setup-state.json: DistroName={ctx.DistroName}");
     }
@@ -2286,7 +2286,7 @@ private static void WriteKeepaliveMarker(SetupContext ctx, string markerPath, in
             StartTimeUtc = DateTimeOffset.UtcNow,
             ProcessName = "wsl"
         };
-        var json = System.Text.Json.JsonSerializer.Serialize(marker, new System.Text.Json.JsonSerializerOptions { WriteIndented = true });
+        var json = System.Text.Json.JsonSerializer.Serialize(marker, SetupConfig.JsonWriteOptions);
         AtomicFile.WriteAllText(markerPath, json);
         ctx.Logger.Info($"Wrote keepalive marker: {markerPath}");
     }

src/OpenClaw.SetupEngine/SetupWizardRunner.cs

@@ -279,7 +279,7 @@ private string WriteAnswerTemplate(IReadOnlyList<WizardTemplateStep> discoveredS
             Steps = discoveredSteps
         };
 
-        var json = JsonSerializer.Serialize(template, new JsonSerializerOptions { WriteIndented = true });
+        var json = JsonSerializer.Serialize(template, SetupConfig.JsonWriteOptions);
         AtomicFile.WriteAllText(basePath, json);
         _ctx.Logger.Info($"Wizard answer template written: {basePath}");
         return basePath;

src/OpenClaw.SetupEngine/TrayArtifactCleanup.cs

@@ -153,8 +153,7 @@ internal static void ResetOnboardingSettings(string appDataDir, SetupLogger logg
 
             if (changed)
             {
-                var updatedJson = System.Text.Json.JsonSerializer.Serialize(dict,
-                    new System.Text.Json.JsonSerializerOptions { WriteIndented = true });
+                var updatedJson = System.Text.Json.JsonSerializer.Serialize(dict, SetupConfig.JsonWriteOptions);
                 AtomicFile.WriteAllText(settingsPath, updatedJson);
                 logger.Info(preserveNodeSettings
                     ? "[Uninstall] Reset onboarding settings (GatewayUrl)"

src/OpenClaw.Shared/ChannelConfigPatchBuilder.cs

@@ -131,7 +131,7 @@ public static ChannelPatchBuildResult BuildPatch(
 
         // Reserialize → re-parse → clone so the returned JsonElement isn't
         // tied to a JsonDocument that goes out of scope on caller side.
-        var json = JsonSerializer.Serialize(root, new JsonSerializerOptions { WriteIndented = true });
+        var json = JsonSerializer.Serialize(root, JsonSerializerOptionsCache.WriteIndented);
         using var doc = JsonDocument.Parse(json);
         return new ChannelPatchBuildResult { Patch = doc.RootElement.Clone() };
     }

src/OpenClaw.Shared/DeviceIdentity.cs

@@ -523,7 +523,7 @@ private void StoreNodeDeviceTokenCore(string token, string[]? scopes)
     /// </summary>
     private static void AtomicWriteKeyFile(string path, DeviceKeyData data)
     {
-        var json = JsonSerializer.Serialize(data, new JsonSerializerOptions { WriteIndented = true });
+        var json = JsonSerializer.Serialize(data, JsonSerializerOptionsCache.WriteIndented);
         var dir = Path.GetDirectoryName(path);
         var tempDir = string.IsNullOrEmpty(dir) ? Environment.CurrentDirectory : dir;
         var tempPath = Path.Combine(tempDir, $".{Path.GetFileName(path)}.{Guid.NewGuid():N}.tmp");

src/OpenClaw.Shared/JsonSerializerOptionsCache.cs

@@ -0,0 +1,20 @@
+using System.Text.Json;
+
+namespace OpenClaw.Shared;
+
+/// <summary>
+/// Shared, reusable <see cref="JsonSerializerOptions"/> singletons.
+/// Prefer these over inline <c>new JsonSerializerOptions { … }</c> allocations
+/// at call sites to avoid repeated heap allocation and settings drift.
+/// </summary>
+internal static class JsonSerializerOptionsCache
+{
+    /// <summary>
+    /// Pretty-print JSON with no additional overrides.
+    /// Suitable for writing human-readable configuration and diagnostic files.
+    /// </summary>
+    internal static readonly JsonSerializerOptions WriteIndented = new()
+    {
+        WriteIndented = true
+    };
+}

src/OpenClaw.Shared/Models.cs

@@ -1789,7 +1789,7 @@ public string DataJson
             if (_cachedDataJson != null) return _cachedDataJson;
             try
             {
-                _cachedDataJson = JsonSerializer.Serialize(Data, new JsonSerializerOptions { WriteIndented = true });
+                _cachedDataJson = JsonSerializer.Serialize(Data, JsonSerializerOptionsCache.WriteIndented);
             }
             catch
             {