diff --git a/app/MindWork AI Studio/Components/JsonTreeView.razor.cs b/app/MindWork AI Studio/Components/JsonTreeView.razor.cs
index a7e79070b..efc3d000a 100644
--- a/app/MindWork AI Studio/Components/JsonTreeView.razor.cs	
+++ b/app/MindWork AI Studio/Components/JsonTreeView.razor.cs	
@@ -1,4 +1,3 @@
-using System.Text.Json;
 using System.Text.Json.Nodes;
 
 using Microsoft.AspNetCore.Components;
@@ -37,7 +36,7 @@ public partial class JsonTreeView : ComponentBase
     private static List<TreeItemData<JsonTreeNode>> CreateChildren(JsonNode? value) => value switch
     {
         JsonObject jsonObject => jsonObject
-            .Select(property => CreateTreeItem(JsonSerializer.Serialize(property.Key), property.Value))
+            .Select(property => CreateTreeItem(JsonValue.Create(property.Key).ToJsonString(), property.Value))
             .ToList(),
         JsonArray jsonArray => jsonArray
             .Select((item, index) => CreateTreeItem($"[{index}]", item))
diff --git a/app/MindWork AI Studio/Tools/ToolCallingSystem/ToolExecutionResult.cs b/app/MindWork AI Studio/Tools/ToolCallingSystem/ToolExecutionResult.cs
index 4708e8aef..243cf5cbc 100644
--- a/app/MindWork AI Studio/Tools/ToolCallingSystem/ToolExecutionResult.cs	
+++ b/app/MindWork AI Studio/Tools/ToolCallingSystem/ToolExecutionResult.cs	
@@ -21,7 +21,11 @@ public sealed class ToolExecutionResult
     /// with every umlaut as six characters. The relaxed encoder escapes only what JSON requires.
     /// </remarks>
     // Internal, so a tool which keeps its result within a budget measures exactly what the model gets:
-    internal static readonly JsonSerializerOptions MODEL_CONTENT_OPTIONS = new() { Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping };
+    internal static readonly JsonSerializerOptions MODEL_CONTENT_OPTIONS = new JsonSerializerOptions
+    {
+        Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping,
+        TypeInfoResolver = ToolExecutionResultJsonContext.Default,
+    }.AsReadOnly();
 
     public string? TextContent { get; init; }
 
diff --git a/app/MindWork AI Studio/Tools/ToolCallingSystem/ToolExecutionResultJsonContext.cs b/app/MindWork AI Studio/Tools/ToolCallingSystem/ToolExecutionResultJsonContext.cs
new file mode 100644
index 000000000..65915c63d
--- /dev/null
+++ b/app/MindWork AI Studio/Tools/ToolCallingSystem/ToolExecutionResultJsonContext.cs	
@@ -0,0 +1,15 @@
+using System.Text.Json.Nodes;
+using System.Text.Json.Serialization;
+
+namespace AIStudio.Tools.ToolCallingSystem;
+
+/// <summary>
+/// The contracts of the options with which a tool result is written for the model, built at compile time.
+/// </summary>
+/// <remarks>
+/// A JSON result is a tree of JSON nodes, which writes itself and needs no contract from the options. The
+/// context is there all the same, so that these options can never fall back to reflection either.
+/// </remarks>
+[JsonSourceGenerationOptions(GenerationMode = JsonSourceGenerationMode.Metadata)]
+[JsonSerializable(typeof(JsonNode))]
+internal sealed partial class ToolExecutionResultJsonContext : JsonSerializerContext;
\ No newline at end of file