Tweak OpenAI JSON schema transforms

src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIAssistantChatClient.cs

@@ -60,7 +60,7 @@ public OpenAIAssistantChatClient(AssistantClient assistantClient, string assista
         // implement the abstractions directly rather than providing adapters on top of the public APIs,
         // the package can provide such implementations separate from what's exposed in the public API.
         Uri providerUrl = typeof(AssistantClient).GetField("_endpoint", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)
-            ?.GetValue(assistantClient) as Uri ?? OpenAIResponseChatClient.DefaultOpenAIEndpoint;
+            ?.GetValue(assistantClient) as Uri ?? OpenAIClientExtensions.DefaultOpenAIEndpoint;
 
         _metadata = new("openai", providerUrl);
     }
@@ -284,13 +284,16 @@ void IDisposable.Dispose()
                     switch (tool)
                     {
                         case AIFunction aiFunction:
-                            bool? strict = aiFunction.AdditionalProperties.TryGetValue(nameof(strict), out var strictValue) && strictValue is bool strictBool ?
+                            bool? strict = aiFunction.AdditionalProperties.TryGetValue(OpenAIClientExtensions.StrictKey, out var strictValue) && strictValue is bool strictBool ?
                                 strictBool :
                                 null;
+
+                            JsonElement jsonSchema = OpenAIClientExtensions.GetSchema(aiFunction, strict);
+
                             runOptions.ToolsOverride.Add(new FunctionToolDefinition(aiFunction.Name)
                             {
                                 Description = aiFunction.Description,
-                                Parameters = BinaryData.FromBytes(JsonSerializer.SerializeToUtf8Bytes(aiFunction.JsonSchema, AssistantJsonContext.Default.JsonElement)),
+                                Parameters = BinaryData.FromBytes(JsonSerializer.SerializeToUtf8Bytes(jsonSchema, AssistantJsonContext.Default.JsonElement)),
                                 StrictParameterSchemaEnabled = strict,
                             });
                             break;
@@ -334,10 +337,10 @@ void IDisposable.Dispose()
                         runOptions.ResponseFormat = AssistantResponseFormat.CreateTextFormat();
                         break;
 
-                    case ChatResponseFormatJson jsonFormat when jsonFormat.Schema is not null:
+                    case ChatResponseFormatJson jsonFormat when OpenAIClientExtensions.StrictSchemaTransformCache.GetOrCreateTransformedSchema(jsonFormat) is { } jsonSchema:
                         runOptions.ResponseFormat = AssistantResponseFormat.CreateJsonSchemaFormat(
                             jsonFormat.SchemaName,
-                            BinaryData.FromBytes(JsonSerializer.SerializeToUtf8Bytes(jsonFormat.Schema, AssistantJsonContext.Default.JsonElement)),
+                            BinaryData.FromBytes(JsonSerializer.SerializeToUtf8Bytes(jsonSchema, AssistantJsonContext.Default.JsonElement)),
                             jsonFormat.SchemaDescription);
                         break;
 
@@ -382,7 +385,7 @@ void AppendSystemInstructions(string? toAppend)
             // to include that information in its responses. System messages should ideally be instead done as instructions to
             // the assistant when the assistant is created.
             if (chatMessage.Role == ChatRole.System ||
-                chatMessage.Role == OpenAIResponseChatClient.ChatRoleDeveloper)
+                chatMessage.Role == OpenAIClientExtensions.ChatRoleDeveloper)
             {
                 foreach (var textContent in chatMessage.Contents.OfType<TextContent>())
                 {

src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIChatClient.cs

@@ -25,15 +25,6 @@ namespace Microsoft.Extensions.AI;
 /// <summary>Represents an <see cref="IChatClient"/> for an OpenAI <see cref="OpenAIClient"/> or <see cref="ChatClient"/>.</summary>
 internal sealed partial class OpenAIChatClient : IChatClient
 {
-    /// <summary>Gets the JSON schema transformer cache conforming to OpenAI restrictions per https://platform.openai.com/docs/guides/structured-outputs?api-mode=responses#supported-schemas.</summary>
-    internal static AIJsonSchemaTransformCache SchemaTransformCache { get; } = new(new()
-    {
-        RequireAllProperties = true,
-        DisallowAdditionalProperties = true,
-        ConvertBooleanSchemas = true,
-        MoveDefaultKeywordToDescription = true,
-    });
-
     /// <summary>Metadata about the client.</summary>
     private readonly ChatClientMetadata _metadata;
 
@@ -54,7 +45,7 @@ public OpenAIChatClient(ChatClient chatClient)
         // implement the abstractions directly rather than providing adapters on top of the public APIs,
         // the package can provide such implementations separate from what's exposed in the public API.
         Uri providerUrl = typeof(ChatClient).GetField("_endpoint", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)
-            ?.GetValue(chatClient) as Uri ?? OpenAIResponseChatClient.DefaultOpenAIEndpoint;
+            ?.GetValue(chatClient) as Uri ?? OpenAIClientExtensions.DefaultOpenAIEndpoint;
         string? model = typeof(ChatClient).GetField("_model", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)
             ?.GetValue(chatClient) as string;
 
@@ -125,12 +116,12 @@ void IDisposable.Dispose()
         {
             if (input.Role == ChatRole.System ||
                 input.Role == ChatRole.User ||
-                input.Role == OpenAIResponseChatClient.ChatRoleDeveloper)
+                input.Role == OpenAIClientExtensions.ChatRoleDeveloper)
             {
                 var parts = ToOpenAIChatContent(input.Contents);
                 yield return
                     input.Role == ChatRole.System ? new SystemChatMessage(parts) { ParticipantName = input.AuthorName } :
-                    input.Role == OpenAIResponseChatClient.ChatRoleDeveloper ? new DeveloperChatMessage(parts) { ParticipantName = input.AuthorName } :
+                    input.Role == OpenAIClientExtensions.ChatRoleDeveloper ? new DeveloperChatMessage(parts) { ParticipantName = input.AuthorName } :
                     new UserChatMessage(parts) { ParticipantName = input.AuthorName };
             }
             else if (input.Role == ChatRole.Tool)
@@ -553,7 +544,7 @@ private ChatCompletionOptions ToOpenAIOptions(ChatOptions? options)
             }
             else if (options.ResponseFormat is ChatResponseFormatJson jsonFormat)
             {
-                result.ResponseFormat = SchemaTransformCache.GetOrCreateTransformedSchema(jsonFormat) is { } jsonSchema ?
+                result.ResponseFormat = OpenAIClientExtensions.StrictSchemaTransformCache.GetOrCreateTransformedSchema(jsonFormat) is { } jsonSchema ?
                     OpenAI.Chat.ChatResponseFormat.CreateJsonSchemaFormat(
                         jsonFormat.SchemaName ?? "json_schema",
                         BinaryData.FromBytes(
@@ -570,12 +561,12 @@ private ChatCompletionOptions ToOpenAIOptions(ChatOptions? options)
     private static ChatTool ToOpenAIChatTool(AIFunction aiFunction)
     {
         bool? strict =
-            aiFunction.AdditionalProperties.TryGetValue("strictJsonSchema", out object? strictObj) &&
+            aiFunction.AdditionalProperties.TryGetValue(OpenAIClientExtensions.StrictKey, out object? strictObj) &&
             strictObj is bool strictValue ?
             strictValue : null;
 
         // Perform transformations making the schema legal per OpenAI restrictions
-        JsonElement jsonSchema = SchemaTransformCache.GetOrCreateTransformedSchema(aiFunction);
+        JsonElement jsonSchema = OpenAIClientExtensions.GetSchema(aiFunction, strict);
 
         // Map to an intermediate model so that redundant properties are skipped.
         var tool = JsonSerializer.Deserialize(jsonSchema, ChatClientJsonContext.Default.ChatToolJson)!;
@@ -622,7 +613,7 @@ private static ChatRole FromOpenAIChatRole(ChatMessageRole role) =>
             ChatMessageRole.User => ChatRole.User,
             ChatMessageRole.Assistant => ChatRole.Assistant,
             ChatMessageRole.Tool => ChatRole.Tool,
-            ChatMessageRole.Developer => OpenAIResponseChatClient.ChatRoleDeveloper,
+            ChatMessageRole.Developer => OpenAIClientExtensions.ChatRoleDeveloper,
             _ => new ChatRole(role.ToString()),
         };
 

src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIClientExtensions.cs

@@ -1,7 +1,9 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System;
 using System.Diagnostics.CodeAnalysis;
+using System.Text.Json;
 using OpenAI;
 using OpenAI.Assistants;
 using OpenAI.Audio;
@@ -14,6 +16,26 @@ namespace Microsoft.Extensions.AI;
 /// <summary>Provides extension methods for working with <see cref="OpenAIClient"/>s.</summary>
 public static class OpenAIClientExtensions
 {
+    /// <summary>Key into AdditionalProperties used to store a strict option.</summary>
+    internal const string StrictKey = "strictJsonSchema";
+
+    /// <summary>Gets the default OpenAI endpoint.</summary>
+    internal static Uri DefaultOpenAIEndpoint { get; } = new("https://api.openai.com/v1");
+
+    /// <summary>Gets a <see cref="ChatRole"/> for "developer".</summary>
+    internal static ChatRole ChatRoleDeveloper { get; } = new ChatRole("developer");
+
+    /// <summary>
+    /// Gets the JSON schema transformer cache conforming to OpenAI <b>strict</b> restrictions per https://platform.openai.com/docs/guides/structured-outputs?api-mode=responses#supported-schemas.
+    /// </summary>
+    internal static AIJsonSchemaTransformCache StrictSchemaTransformCache { get; } = new(new()
+    {
+        DisallowAdditionalProperties = true,
+        ConvertBooleanSchemas = true,
+        MoveDefaultKeywordToDescription = true,
+        RequireAllProperties = true,
+    });
+
     /// <summary>Gets an <see cref="IChatClient"/> for use with this <see cref="ChatClient"/>.</summary>
     /// <param name="chatClient">The client.</param>
     /// <returns>An <see cref="IChatClient"/> that can be used to converse via the <see cref="ChatClient"/>.</returns>
@@ -52,4 +74,10 @@ public static ISpeechToTextClient AsISpeechToTextClient(this AudioClient audioCl
     /// <returns>An <see cref="IEmbeddingGenerator{String, Embedding}"/> that can be used to generate embeddings via the <see cref="EmbeddingClient"/>.</returns>
     public static IEmbeddingGenerator<string, Embedding<float>> AsIEmbeddingGenerator(this EmbeddingClient embeddingClient, int? defaultModelDimensions = null) =>
         new OpenAIEmbeddingGenerator(embeddingClient, defaultModelDimensions);
+
+    /// <summary>Gets the JSON schema to use from the function.</summary>
+    internal static JsonElement GetSchema(AIFunction function, bool? strict) =>
+        strict is true ?
+            StrictSchemaTransformCache.GetOrCreateTransformedSchema(function) :
+            function.JsonSchema;
 }

src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponseChatClient.cs

@@ -13,7 +13,6 @@
 using System.Threading.Tasks;
 using Microsoft.Shared.Diagnostics;
 using OpenAI.Responses;
-using static Microsoft.Extensions.AI.OpenAIChatClient;
 
 #pragma warning disable S907 // "goto" statement should not be used
 #pragma warning disable S1067 // Expressions should not be too complex
@@ -26,12 +25,6 @@ namespace Microsoft.Extensions.AI;
 /// <summary>Represents an <see cref="IChatClient"/> for an <see cref="OpenAIResponseClient"/>.</summary>
 internal sealed partial class OpenAIResponseChatClient : IChatClient
 {
-    /// <summary>Gets the default OpenAI endpoint.</summary>
-    internal static Uri DefaultOpenAIEndpoint { get; } = new("https://api.openai.com/v1");
-
-    /// <summary>Gets a <see cref="ChatRole"/> for "developer".</summary>
-    internal static ChatRole ChatRoleDeveloper { get; } = new ChatRole("developer");
-
     /// <summary>Metadata about the client.</summary>
     private readonly ChatClientMetadata _metadata;
 
@@ -52,7 +45,7 @@ public OpenAIResponseChatClient(OpenAIResponseClient responseClient)
         // implement the abstractions directly rather than providing adapters on top of the public APIs,
         // the package can provide such implementations separate from what's exposed in the public API.
         Uri providerUrl = typeof(OpenAIResponseClient).GetField("_endpoint", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)
-            ?.GetValue(responseClient) as Uri ?? DefaultOpenAIEndpoint;
+            ?.GetValue(responseClient) as Uri ?? OpenAIClientExtensions.DefaultOpenAIEndpoint;
         string? model = typeof(OpenAIResponseClient).GetField("_model", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)
             ?.GetValue(responseClient) as string;
 
@@ -336,7 +329,7 @@ private static ChatRole ToChatRole(MessageRole? role) =>
         role switch
         {
             MessageRole.System => ChatRole.System,
-            MessageRole.Developer => ChatRoleDeveloper,
+            MessageRole.Developer => OpenAIClientExtensions.ChatRoleDeveloper,
             MessageRole.User => ChatRole.User,
             _ => ChatRole.Assistant,
         };
@@ -380,10 +373,17 @@ private ResponseCreationOptions ToOpenAIResponseCreationOptions(ChatOptions? opt
             {
                 switch (tool)
                 {
-                    case AIFunction af:
-                        var oaitool = JsonSerializer.Deserialize(SchemaTransformCache.GetOrCreateTransformedSchema(af), ResponseClientJsonContext.Default.ResponseToolJson)!;
+                    case AIFunction aiFunction:
+                        bool strict =
+                            aiFunction.AdditionalProperties.TryGetValue(OpenAIClientExtensions.StrictKey, out object? strictObj) &&
+                            strictObj is bool strictValue &&
+                            strictValue;
+
+                        JsonElement jsonSchema = OpenAIClientExtensions.GetSchema(aiFunction, strict);
+
+                        var oaitool = JsonSerializer.Deserialize(jsonSchema, ResponseClientJsonContext.Default.ResponseToolJson)!;
                         var functionParameters = BinaryData.FromBytes(JsonSerializer.SerializeToUtf8Bytes(oaitool, ResponseClientJsonContext.Default.ResponseToolJson));
-                        result.Tools.Add(ResponseTool.CreateFunctionTool(af.Name, af.Description, functionParameters));
+                        result.Tools.Add(ResponseTool.CreateFunctionTool(aiFunction.Name, aiFunction.Description, functionParameters, strict));
                         break;
 
                     case HostedWebSearchTool:
@@ -440,7 +440,7 @@ private ResponseCreationOptions ToOpenAIResponseCreationOptions(ChatOptions? opt
             {
                 result.TextOptions = new()
                 {
-                    TextFormat = SchemaTransformCache.GetOrCreateTransformedSchema(jsonFormat) is { } jsonSchema ?
+                    TextFormat = OpenAIClientExtensions.StrictSchemaTransformCache.GetOrCreateTransformedSchema(jsonFormat) is { } jsonSchema ?
                         ResponseTextFormat.CreateJsonSchemaFormat(
                             jsonFormat.SchemaName ?? "json_schema",
                             BinaryData.FromBytes(JsonSerializer.SerializeToUtf8Bytes(jsonSchema, ResponseClientJsonContext.Default.JsonElement)),
@@ -460,7 +460,7 @@ private static IEnumerable<ResponseItem> ToOpenAIResponseItems(
         foreach (ChatMessage input in inputs)
         {
             if (input.Role == ChatRole.System ||
-                input.Role == ChatRoleDeveloper)
+                input.Role == OpenAIClientExtensions.ChatRoleDeveloper)
             {
                 string text = input.Text;
                 if (!string.IsNullOrWhiteSpace(text))