Made the JSON types of the providers settable instead of init-only

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

@@ -10,4 +10,12 @@ namespace AIStudio.Provider.Anthropic;
 /// thinking blocks, and the thinking blocks have to return exactly as they arrived — reading and
 /// rebuilding them would risk changing them.
 /// </remarks>
-public sealed record AnthropicMessage(IList<JsonElement> Content, string Role = "assistant") : IMessage<IList<JsonElement>>;
+public sealed record AnthropicMessage(IList<JsonElement> Content, string Role = "assistant") : IMessage<IList<JsonElement>>
+{
+    //
+    // The properties of the parameters, declared again to be settable, as the messages demand it. Keep them in
+    // the order of the parameters, which is the order they get written in:
+    //
+    public IList<JsonElement> Content { get; set; } = Content;
+    public string Role { get; set; } = Role;
+}

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

@@ -14,5 +14,5 @@ public sealed record AnthropicStreamMessage
     /// <summary>
     /// What the request carried, where the stream states it.
     /// </summary>
-    public AnthropicUsage? Usage { get; init; }
+    public AnthropicUsage? Usage { get; set; }
 }

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

@@ -11,11 +11,11 @@ namespace AIStudio.Provider.Anthropic;
 /// </remarks>
 public sealed record AnthropicTool
 {
-    public string Name { get; init; } = string.Empty;
+    public string Name { get; set; } = string.Empty;
 
-    public string Description { get; init; } = string.Empty;
+    public string Description { get; set; } = string.Empty;
 
-    public bool Strict { get; init; }
+    public bool Strict { get; set; }
 
-    public JsonElement InputSchema { get; init; }
+    public JsonElement InputSchema { get; set; }
 }

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

@@ -4,11 +4,11 @@ namespace AIStudio.Provider.Anthropic;
 
 public sealed record AnthropicToolResultContent
 {
-    public string Type { get; init; } = "tool_result";
+    public string Type { get; set; } = "tool_result";
 
-    public string ToolUseId { get; init; } = string.Empty;
+    public string ToolUseId { get; set; } = string.Empty;
 
-    public string Content { get; init; } = string.Empty;
+    public string Content { get; set; } = string.Empty;
 
     /// <summary>
     /// Whether the tool failed rather than returning a result.
@@ -18,5 +18,5 @@ public sealed record AnthropicToolResultContent
     /// result stays byte-identical to what earlier versions sent.
     /// </remarks>
     [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]
-    public bool IsError { get; init; }
+    public bool IsError { get; set; }
 }

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

@@ -7,4 +7,12 @@ namespace AIStudio.Provider.Anthropic;
 /// All results of one turn belong in a single message. Splitting them across several messages
 /// teaches the model to stop asking for more than one tool at a time.
 /// </remarks>
-public sealed record AnthropicToolResultMessage(IList<AnthropicToolResultContent> Content, string Role = "user") : IMessage<IList<AnthropicToolResultContent>>;
+public sealed record AnthropicToolResultMessage(IList<AnthropicToolResultContent> Content, string Role = "user") : IMessage<IList<AnthropicToolResultContent>>
+{
+    //
+    // The properties of the parameters, declared again to be settable, as the messages demand it. Keep them in
+    // the order of the parameters, which is the order they get written in:
+    //
+    public IList<AnthropicToolResultContent> Content { get; set; } = Content;
+    public string Role { get; set; } = Role;
+}

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

@@ -23,17 +23,17 @@ public sealed record AnthropicUsage
     /// <summary>
     /// What the request carried after its last cache breakpoint, which is all of it without caching.
     /// </summary>
-    public int? InputTokens { get; init; }
+    public int? InputTokens { get; set; }
 
     /// <summary>
     /// What the request wrote to the cache.
     /// </summary>
-    public int? CacheCreationInputTokens { get; init; }
+    public int? CacheCreationInputTokens { get; set; }
 
     /// <summary>
     /// What the request read from the cache.
     /// </summary>
-    public int? CacheReadInputTokens { get; init; }
+    public int? CacheReadInputTokens { get; set; }
 
     /// <summary>
     /// States what this block reports, as far as it can be believed.

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>();
 }

app/MindWork AI Studio/Provider/Anthropic/SubContentBase64Image.cs

@@ -4,7 +4,7 @@ public record SubContentBase64Image : ISubContentImageSource
 {
     public SubContentImageType Type => SubContentImageType.BASE64;
 
-    public string MediaType { get; init; } = string.Empty;
+    public string MediaType { get; set; } = string.Empty;
     
-    public string Data { get; init; } = string.Empty;
+    public string Data { get; set; } = string.Empty;
 }

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

@@ -4,6 +4,15 @@ namespace AIStudio.Provider.Anthropic;
 
 public record SubContentImage(SubContentType Type, ISubContentImageSource Source) : ISubContent
 {
+    //
+    // The properties of the parameters, declared again to be settable. The source generation of System.Text.Json
+    // sets every init-only property while it creates the object, also one missing in the JSON, so its value from
+    // the parameterless constructor would get lost. Keep them first and in the order of the parameters, which is
+    // the order they get written in:
+    //
+    public SubContentType Type { get; set; } = Type;
+    public ISubContentImageSource Source { get; set; } = Source;
+
     public SubContentImage() : this(SubContentType.IMAGE, new SubContentImageUrl())
     {
     }

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

@@ -4,5 +4,5 @@ public record SubContentImageUrl : ISubContentImageSource
 {
     public SubContentImageType Type => SubContentImageType.URL;
 
-    public string Url { get; init; } = string.Empty;
+    public string Url { get; set; } = string.Empty;
 }

app/MindWork AI Studio/Provider/EmbeddingResponse.cs

@@ -2,13 +2,13 @@
 
 public sealed record EmbeddingResponse
 {
-    public string? Id { get; init; }
+    public string? Id { get; set; }
     
-    public string? Object { get; init; }
+    public string? Object { get; set; }
     
-    public List<EmbeddingData>? Data { get; init; }
+    public List<EmbeddingData>? Data { get; set; }
     
-    public string? Model { get; init; }
+    public string? Model { get; set; }
     
-    public EmbeddingUsage? Usage { get; init; }
+    public EmbeddingUsage? Usage { get; set; }
 }

app/MindWork AI Studio/Provider/Google/GoogleEmbedding.cs

@@ -2,5 +2,5 @@
 
 public sealed record GoogleEmbedding
 {
-    public List<float>? Values { get; init; }
+    public List<float>? Values { get; set; }
 }

app/MindWork AI Studio/Provider/Google/GoogleEmbeddingResponse.cs

@@ -6,9 +6,13 @@ namespace AIStudio.Provider.Google;
 public sealed record GoogleEmbeddingResponse
 {
     [JsonConverter(typeof(GoogleEmbeddingListConverter))]
-    public List<GoogleEmbedding>? Embedding { get; init; }
+    public List<GoogleEmbedding>? Embedding { get; set; }
 
-    private sealed class GoogleEmbeddingListConverter : JsonConverter<List<GoogleEmbedding>>
+    /// <remarks>
+    /// Internal rather than private: the JSON context of the providers has to reach the converter, else it reads
+    /// the embeddings without it.
+    /// </remarks>
+    internal sealed class GoogleEmbeddingListConverter : JsonConverter<List<GoogleEmbedding>>
     {
         public override List<GoogleEmbedding> Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {

app/MindWork AI Studio/Provider/IMessage.cs

@@ -11,5 +11,5 @@ public interface IMessage<T> : IMessageBase
     /// The content encapsulates the core information or data being transmitted,
     /// and its type can vary based on the specific implementation or use case.
     /// </summary>
-    public T Content { get; init; }
+    public T Content { get; set; }
 }

app/MindWork AI Studio/Provider/IMessageBase.cs

@@ -10,5 +10,5 @@ public interface IMessageBase
     /// This property typically identifies whether the entity is acting
     /// as a user, assistant, or system in the context of the interaction.
     /// </summary>
-    public string Role { get; init; }
+    public string Role { get; set; }
 }

app/MindWork AI Studio/Provider/OpenAI/AssistantToolCallMessage.cs

@@ -5,12 +5,12 @@ namespace AIStudio.Provider.OpenAI;
 
 public sealed record AssistantToolCallMessage : IMessageBase
 {
-    public string Role { get; init; } = "assistant";
+    public string Role { get; set; } = "assistant";
 
-    public JsonElement? Content { get; init; }
+    public JsonElement? Content { get; set; }
 
     [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
-    public string? ReasoningContent { get; init; }
+    public string? ReasoningContent { get; set; }
 
-    public IList<ChatCompletionToolCall> ToolCalls { get; init; } = [];
+    public IList<ChatCompletionToolCall> ToolCalls { get; set; } = [];
 }

app/MindWork AI Studio/Provider/OpenAI/ChatCompletionAPIRequest.cs

@@ -14,15 +14,25 @@ public record ChatCompletionAPIRequest(
     bool Stream
 )
 {
+    //
+    // The properties of the parameters, declared again to be settable. The source generation of System.Text.Json
+    // sets every init-only property while it creates the object, also one missing in the JSON, so its value from
+    // the parameterless constructor would get lost. Keep them first and in the order of the parameters, which is
+    // the order they get written in:
+    //
+    public string Model { get; set; } = Model;
+    public IList<IMessageBase> Messages { get; set; } = Messages;
+    public bool Stream { get; set; } = Stream;
+
     public ChatCompletionAPIRequest() : this(string.Empty, [], true)
     {
     }
 
     [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
-    public IList<object>? Tools { get; init; }
+    public IList<object>? Tools { get; set; }
 
     [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
-    public bool? ParallelToolCalls { get; init; }
+    public bool? ParallelToolCalls { get; set; }
 
     /// <summary>
     /// Asks a streamed request to end with what it cost.
@@ -35,7 +45,10 @@ public record ChatCompletionAPIRequest(
     [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
     public ChatCompletionStreamOptions? StreamOptions => this.Stream ? ChatCompletionStreamOptions.INCLUDE_USAGE : null;
     
-    // 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>();
 }

app/MindWork AI Studio/Provider/OpenAI/ChatCompletionChoice.cs

@@ -7,6 +7,14 @@ namespace AIStudio.Provider.OpenAI;
 /// <param name="Delta">The delta text of the choice.</param>
 public record ChatCompletionChoice(int Index, ChatCompletionDelta Delta)
 {
+    //
+    // The properties of the parameters, declared again to be settable. The source generation of System.Text.Json
+    // sets every init-only property while it creates the object, also one missing in the JSON, so its value from
+    // the parameterless constructor would get lost. Keep them first and in the order of the parameters:
+    //
+    public int Index { get; set; } = Index;
+    public ChatCompletionDelta Delta { get; set; } = Delta;
+
     public ChatCompletionChoice() : this(0, new())
     {
     }

app/MindWork AI Studio/Provider/OpenAI/ChatCompletionDelta.cs

@@ -9,7 +9,7 @@ namespace AIStudio.Provider.OpenAI;
 public sealed record ChatCompletionDelta
 {
     [JsonPropertyName("content")]
-    public JsonElement? RawContent { get; init; }
+    public JsonElement? RawContent { get; set; }
 
     [JsonIgnore]
     public string Content => ChatCompletionContent.GetText(this.RawContent) ?? string.Empty;

app/MindWork AI Studio/Provider/OpenAI/ChatCompletionDeltaStreamLine.cs

@@ -11,6 +11,19 @@ namespace AIStudio.Provider.OpenAI;
 /// <param name="Choices">The choices made by the AI.</param>
 public record ChatCompletionDeltaStreamLine(string Id, string Object, uint Created, string Model, string SystemFingerprint, IList<ChatCompletionChoice> Choices) : IResponseStreamLine
 {
+    //
+    // The properties of the parameters, declared again to be settable. The source generation of System.Text.Json
+    // sets every init-only property while it creates the object, also one missing in the JSON, so its value from
+    // the parameterless constructor would get lost, e.g., the empty list of choices of the line which carries the
+    // usage. Keep them first and in the order of the parameters:
+    //
+    public string Id { get; set; } = Id;
+    public string Object { get; set; } = Object;
+    public uint Created { get; set; } = Created;
+    public string Model { get; set; } = Model;
+    public string SystemFingerprint { get; set; } = SystemFingerprint;
+    public IList<ChatCompletionChoice> Choices { get; set; } = Choices;
+
     public ChatCompletionDeltaStreamLine() : this(string.Empty, string.Empty, 0, string.Empty, string.Empty, [])
     {
     }
@@ -25,7 +38,7 @@ public record ChatCompletionDeltaStreamLine(string Id, string Object, uint Creat
     /// line of its own which carries no choices -- which is why the usage is read apart from the
     /// content rather than next to it.
     /// </remarks>
-    public ChatCompletionUsage? Usage { get; init; }
+    public ChatCompletionUsage? Usage { get; set; }
 
     /// <inheritdoc />
     public bool ContainsContent() => this.Choices.Count > 0;

app/MindWork AI Studio/Provider/OpenAI/ChatCompletionFunctionDeclaration.cs

@@ -7,11 +7,11 @@ namespace AIStudio.Provider.OpenAI;
 /// </summary>
 public sealed record ChatCompletionFunctionDeclaration
 {
-    public string Name { get; init; } = string.Empty;
+    public string Name { get; set; } = string.Empty;
 
-    public string Description { get; init; } = string.Empty;
+    public string Description { get; set; } = string.Empty;
 
-    public JsonElement Parameters { get; init; }
+    public JsonElement Parameters { get; set; }
 
-    public bool Strict { get; init; }
+    public bool Strict { get; set; }
 }

app/MindWork AI Studio/Provider/OpenAI/ChatCompletionFunctionTool.cs

@@ -5,7 +5,7 @@ namespace AIStudio.Provider.OpenAI;
 /// </summary>
 public sealed record ChatCompletionFunctionTool
 {
-    public string Type { get; init; } = "function";
+    public string Type { get; set; } = "function";
 
-    public ChatCompletionFunctionDeclaration Function { get; init; } = new();
+    public ChatCompletionFunctionDeclaration Function { get; set; } = new();
 }

app/MindWork AI Studio/Provider/OpenAI/ChatCompletionStreamDelta.cs

@@ -16,7 +16,7 @@ public sealed record ChatCompletionStreamDelta
     /// The content as it arrived: a string for most providers, a list of parts for some.
     /// </summary>
     [JsonPropertyName("content")]
-    public JsonElement? RawContent { get; init; }
+    public JsonElement? RawContent { get; set; }
 
     /// <summary>
     /// The text of this fragment, whichever shape it arrived in.
@@ -27,10 +27,10 @@ public sealed record ChatCompletionStreamDelta
     /// <summary>
     /// The reasoning text some providers stream next to the answer.
     /// </summary>
-    public string? ReasoningContent { get; init; }
+    public string? ReasoningContent { get; set; }
 
     /// <summary>
     /// The fragments of the tool calls the model is asking for.
     /// </summary>
-    public IList<ChatCompletionToolCallDelta?>? ToolCalls { get; init; }
+    public IList<ChatCompletionToolCallDelta?>? ToolCalls { get; set; }
 }

app/MindWork AI Studio/Provider/OpenAI/ChatCompletionToolCall.cs

@@ -5,12 +5,12 @@ namespace AIStudio.Provider.OpenAI;
 
 public sealed record ChatCompletionToolCall
 {
-    public string? Id { get; init; }
+    public string? Id { get; set; }
 
-    public string? Type { get; init; } = "function";
+    public string? Type { get; set; } = "function";
 
-    public ChatCompletionToolFunction? Function { get; init; }
+    public ChatCompletionToolFunction? Function { get; set; }
 
     [JsonExtensionData]
-    public IDictionary<string, JsonElement> AdditionalMetadata { get; init; } = new Dictionary<string, JsonElement>();
+    public IDictionary<string, JsonElement> AdditionalMetadata { get; set; } = new Dictionary<string, JsonElement>();
 }

app/MindWork AI Studio/Provider/OpenAI/ChatCompletionToolFunction.cs

@@ -2,7 +2,7 @@ namespace AIStudio.Provider.OpenAI;
 
 public sealed record ChatCompletionToolFunction
 {
-    public string? Name { get; init; }
+    public string? Name { get; set; }
 
-    public string? Arguments { get; init; }
+    public string? Arguments { get; set; }
 }

app/MindWork AI Studio/Provider/OpenAI/ChatCompletionToolStreamLine.cs

@@ -21,5 +21,5 @@ public sealed record ChatCompletionToolStreamLine(string? Id, IList<ChatCompleti
     /// ChatCompletionAPIRequest asks for it, the requests of the tool rounds included. Not a
     /// positional parameter, because nobody but the serializer ever builds this line.
     /// </remarks>
-    public ChatCompletionUsage? Usage { get; init; }
+    public ChatCompletionUsage? Usage { get; set; }
 }

app/MindWork AI Studio/Provider/OpenAI/ChatCompletionUsage.cs

@@ -17,7 +17,7 @@ public sealed record ChatCompletionUsage
     /// <summary>
     /// What everything sent to the model cost.
     /// </summary>
-    public int? PromptTokens { get; init; }
+    public int? PromptTokens { get; set; }
 
     /// <summary>
     /// States what this block reports, as far as it can be believed.

app/MindWork AI Studio/Provider/OpenAI/ISubContent.cs

@@ -8,5 +8,5 @@ public interface ISubContent
     /// <summary>
     /// The type of the sub-content.
     /// </summary>
-    public SubContentType Type { get; init; }
+    public SubContentType Type { get; set; }
 }

app/MindWork AI Studio/Provider/OpenAI/ISubContentImageUrl.cs

@@ -15,5 +15,5 @@ public interface ISubContentImageUrl
     /// <summary>
     /// The URL or base64-encoded data URI of the image.
     /// </summary>
-    public string Url { get; init; }
+    public string Url { get; set; }
 }

app/MindWork AI Studio/Provider/OpenAI/MultimodalMessage.cs

@@ -7,6 +7,15 @@ namespace AIStudio.Provider.OpenAI;
 /// <param name="Role">The role of the message.</param>
 public record MultimodalMessage(List<ISubContent> Content, string Role) : IMessage<List<ISubContent>>
 {
+    //
+    // The properties of the parameters, declared again to be settable. The source generation of System.Text.Json
+    // sets every init-only property while it creates the object, also one missing in the JSON, so its value from
+    // the parameterless constructor would get lost. Keep them first and in the order of the parameters, which is
+    // the order they get written in:
+    //
+    public List<ISubContent> Content { get; set; } = Content;
+    public string Role { get; set; } = Role;
+
     public MultimodalMessage() : this([], string.Empty)
     {
     }

app/MindWork AI Studio/Provider/OpenAI/ResponsesAPIRequest.cs

@@ -17,11 +17,26 @@ public record ResponsesAPIRequest(
     bool Store,
     IList<object> Tools)
 {
+    //
+    // The properties of the parameters, declared again to be settable. The source generation of System.Text.Json
+    // sets every init-only property while it creates the object, also one missing in the JSON, so its value from
+    // the parameterless constructor would get lost. Keep them first and in the order of the parameters, which is
+    // the order they get written in:
+    //
+    public string Model { get; set; } = Model;
+    public IList<object> Input { get; set; } = Input;
+    public bool Stream { get; set; } = Stream;
+    public bool Store { get; set; } = Store;
+    public IList<object> Tools { get; set; } = Tools;
+
     public ResponsesAPIRequest() : this(string.Empty, [], true, false, [])
     {
     }
-    
-    // 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>();
 }

app/MindWork AI Studio/Provider/OpenAI/ResponsesFunctionCallOutputItem.cs

@@ -5,9 +5,9 @@ namespace AIStudio.Provider.OpenAI;
 /// </summary>
 public sealed record ResponsesFunctionCallOutputItem
 {
-    public string Type { get; init; } = "function_call_output";
+    public string Type { get; set; } = "function_call_output";
 
-    public string CallId { get; init; } = string.Empty;
+    public string CallId { get; set; } = string.Empty;
 
-    public string Output { get; init; } = string.Empty;
+    public string Output { get; set; } = string.Empty;
 }

app/MindWork AI Studio/Provider/OpenAI/ResponsesFunctionTool.cs

@@ -7,13 +7,13 @@ namespace AIStudio.Provider.OpenAI;
 /// </summary>
 public sealed record ResponsesFunctionTool
 {
-    public string Type { get; init; } = "function";
+    public string Type { get; set; } = "function";
 
-    public string Name { get; init; } = string.Empty;
+    public string Name { get; set; } = string.Empty;
 
-    public string Description { get; init; } = string.Empty;
+    public string Description { get; set; } = string.Empty;
 
-    public JsonElement Parameters { get; init; }
+    public JsonElement Parameters { get; set; }
 
-    public bool Strict { get; init; }
+    public bool Strict { get; set; }
 }

app/MindWork AI Studio/Provider/OpenAI/ResponsesResponse.cs

@@ -17,18 +17,18 @@ public sealed record ResponsesResponse
     /// </remarks>
     private static readonly HashSet<string> OUTPUT_ITEMS_LEAVING_THE_INPUT_ALONE = ["message", "reasoning", "function_call"];
 
-    public string Id { get; init; } = string.Empty;
+    public string Id { get; set; } = string.Empty;
 
-    public string Model { get; init; } = string.Empty;
+    public string Model { get; set; } = string.Empty;
 
-    public string? OutputText { get; init; }
+    public string? OutputText { get; set; }
 
-    public IList<JsonElement> Output { get; init; } = [];
+    public IList<JsonElement> Output { get; set; } = [];
 
     /// <summary>
     /// What OpenAI says the response cost. Only the completed response carries it.
     /// </summary>
-    public ResponsesUsage? Usage { get; init; }
+    public ResponsesUsage? Usage { get; set; }
 
     /// <summary>
     /// States what the request of this response carried, as far as it can be believed.

app/MindWork AI Studio/Provider/OpenAI/ResponsesUsage.cs

@@ -17,7 +17,7 @@ public sealed record ResponsesUsage
     /// <summary>
     /// What everything sent to the model cost, the cached part included.
     /// </summary>
-    public int? InputTokens { get; init; }
+    public int? InputTokens { get; set; }
 
     /// <summary>
     /// States what this block reports, as far as it can be believed.

app/MindWork AI Studio/Provider/OpenAI/SubContentImageUrl.cs

@@ -5,6 +5,15 @@ namespace AIStudio.Provider.OpenAI;
 /// </summary>
 public record SubContentImageUrl(SubContentType Type, string ImageUrl) : ISubContent
 {
+    //
+    // The properties of the parameters, declared again to be settable. The source generation of System.Text.Json
+    // sets every init-only property while it creates the object, also one missing in the JSON, so its value from
+    // the parameterless constructor would get lost. Keep them first and in the order of the parameters, which is
+    // the order they get written in:
+    //
+    public SubContentType Type { get; set; } = Type;
+    public string ImageUrl { get; set; } = ImageUrl;
+
     public SubContentImageUrl() : this(SubContentType.IMAGE_URL, string.Empty)
     {
     }

app/MindWork AI Studio/Provider/OpenAI/SubContentImageUrlData.cs

@@ -13,5 +13,5 @@ namespace AIStudio.Provider.OpenAI;
 public record SubContentImageUrlData : ISubContentImageUrl
 {
     /// <inheritdoc />
-    public string Url { get; init; } = string.Empty;
+    public string Url { get; set; } = string.Empty;
 }

app/MindWork AI Studio/Provider/OpenAI/SubContentImageUrlNested.cs

@@ -12,6 +12,15 @@ namespace AIStudio.Provider.OpenAI;
 /// </remarks>
 public record SubContentImageUrlNested(SubContentType Type, ISubContentImageUrl ImageUrl) : ISubContent
 {
+    //
+    // The properties of the parameters, declared again to be settable. The source generation of System.Text.Json
+    // sets every init-only property while it creates the object, also one missing in the JSON, so its value from
+    // the parameterless constructor would get lost. Keep them first and in the order of the parameters, which is
+    // the order they get written in:
+    //
+    public SubContentType Type { get; set; } = Type;
+    public ISubContentImageUrl ImageUrl { get; set; } = ImageUrl;
+
     public SubContentImageUrlNested() : this(SubContentType.IMAGE_URL, new SubContentImageUrlData())
     {
     }

app/MindWork AI Studio/Provider/OpenAI/SubContentInputImage.cs

@@ -8,6 +8,15 @@ namespace AIStudio.Provider.OpenAI;
 /// </remarks>
 public record SubContentInputImage(SubContentType Type, string ImageUrl) : ISubContent
 {
+    //
+    // The properties of the parameters, declared again to be settable. The source generation of System.Text.Json
+    // sets every init-only property while it creates the object, also one missing in the JSON, so its value from
+    // the parameterless constructor would get lost. Keep them first and in the order of the parameters, which is
+    // the order they get written in:
+    //
+    public SubContentType Type { get; set; } = Type;
+    public string ImageUrl { get; set; } = ImageUrl;
+
     public SubContentInputImage() : this(SubContentType.INPUT_IMAGE, string.Empty)
     {
     }

app/MindWork AI Studio/Provider/OpenAI/SubContentInputText.cs

@@ -8,6 +8,15 @@ namespace AIStudio.Provider.OpenAI;
 /// </remarks>
 public record SubContentInputText(SubContentType Type, string Text) : ISubContent
 {
+    //
+    // The properties of the parameters, declared again to be settable. The source generation of System.Text.Json
+    // sets every init-only property while it creates the object, also one missing in the JSON, so its value from
+    // the parameterless constructor would get lost. Keep them first and in the order of the parameters, which is
+    // the order they get written in:
+    //
+    public SubContentType Type { get; set; } = Type;
+    public string Text { get; set; } = Text;
+
     public SubContentInputText() : this(SubContentType.INPUT_TEXT, string.Empty)
     {
     }

app/MindWork AI Studio/Provider/OpenAI/SubContentText.cs

@@ -5,6 +5,15 @@ namespace AIStudio.Provider.OpenAI;
 /// </summary>
 public record SubContentText(SubContentType Type, string Text) : ISubContent
 {
+    //
+    // The properties of the parameters, declared again to be settable. The source generation of System.Text.Json
+    // sets every init-only property while it creates the object, also one missing in the JSON, so its value from
+    // the parameterless constructor would get lost. Keep them first and in the order of the parameters, which is
+    // the order they get written in:
+    //
+    public SubContentType Type { get; set; } = Type;
+    public string Text { get; set; } = Text;
+
     public SubContentText() : this(SubContentType.TEXT, string.Empty)
     {
     }

app/MindWork AI Studio/Provider/OpenAI/TextMessage.cs

@@ -7,6 +7,15 @@ namespace AIStudio.Provider.OpenAI;
 /// <param name="Role">The role of the message.</param>
 public record TextMessage(string Content, string Role) : IMessage<string>
 {
+    //
+    // The properties of the parameters, declared again to be settable. The source generation of System.Text.Json
+    // sets every init-only property while it creates the object, also one missing in the JSON, so its value from
+    // the parameterless constructor would get lost. Keep them first and in the order of the parameters, which is
+    // the order they get written in:
+    //
+    public string Content { get; set; } = Content;
+    public string Role { get; set; } = Role;
+
     public TextMessage() : this(string.Empty, string.Empty)
     {
     }

app/MindWork AI Studio/Provider/OpenAI/ToolResultMessage.cs

@@ -2,9 +2,9 @@ namespace AIStudio.Provider.OpenAI;
 
 public sealed record ToolResultMessage : IMessage<string>
 {
-    public string Role { get; init; } = "tool";
+    public string Role { get; set; } = "tool";
 
-    public string Content { get; init; } = string.Empty;
+    public string Content { get; set; } = string.Empty;
 
-    public string ToolCallId { get; init; } = string.Empty;
+    public string ToolCallId { get; set; } = string.Empty;
 }

app/MindWork AI Studio/Tools/Source.cs

@@ -5,4 +5,15 @@ namespace AIStudio.Tools;
 /// </summary>
 /// <param name="Title">The title of the source.</param>
 /// <param name="URL">The URL of the source.</param>
-public record Source(string Title, string URL, SourceOrigin Origin) : ISource;
+public record Source(string Title, string URL, SourceOrigin Origin) : ISource
+{
+    //
+    // The properties of the parameters, declared again to be settable. A derived record which passes a value of
+    // its own to one of them, as the search results of Perplexity do with the origin, would otherwise lose it:
+    // the source generation of System.Text.Json sets every init-only property while it creates the object, also
+    // one missing in the JSON. Keep them in the order of the parameters, which is the order they get stored in:
+    //
+    public string Title { get; set; } = Title;
+    public string URL { get; set; } = URL;
+    public SourceOrigin Origin { get; set; } = Origin;
+}