Generated the JSON contracts of providers, the runtime, and services at compile time (#1150)

app/MindWork AI Studio/Provider/Anthropic/ChatRequest.cs

@@ -10,7 +10,11 @@ namespace AIStudio.Provider.Anthropic;
 /// <param name="MaxTokens">The maximum number of tokens to generate.</param>
 /// <param name="Stream">Whether to stream the chat completion.</param>
 /// <param name="System">The system prompt for the chat completion.</param>
-public readonly record struct ChatRequest(
+/// <remarks>
+/// Not readonly, so that its properties can be settable: the source generation of System.Text.Json refuses to
+/// write extension data which is init-only.
+/// </remarks>
+public record struct ChatRequest(
     string Model,
     IList<IMessageBase> Messages,
     int MaxTokens,
@@ -26,9 +30,12 @@ public readonly record struct ChatRequest(
     /// tools at all, and the final round of a tool conversation has to offer none.
     /// </remarks>
     [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
-    public IList<AnthropicTool>? Tools { get; init; }
+    public IList<AnthropicTool>? Tools { get; set; }
 
-    // Attention: The "required" modifier is not supported for [JsonExtensionData].
+    //
+    // Attention: The "required" modifier is not supported for [JsonExtensionData], and neither is init: the source
+    // generation of System.Text.Json refuses to write the request at all then.
+    //
     [JsonExtensionData]
-    public IDictionary<string, object> AdditionalApiParameters { get; init; } = new Dictionary<string, object>();
+    public IDictionary<string, object> AdditionalApiParameters { get; set; } = new Dictionary<string, object>();
 }