Add ChatOptions.AllowMultipleToolCalls

src/Libraries/Microsoft.Extensions.AI.Abstractions/ChatCompletion/ChatOptions.cs

@@ -93,6 +93,23 @@ public string? ChatThreadId
     /// </remarks>
     public IList<string>? StopSequences { get; set; }
 
+    /// <summary>
+    /// Gets or sets a flag to indicate whether a single response is allowed to include multiple tool calls.
+    /// If <see langword="false"/>, the <see cref="IChatClient"/> is asked to return a maximum of one tool call per request.
+    /// If <see langword="true"/>, there is no limit.
+    /// If <see langword="null"/>, the provider may select its own default.
+    /// </summary>
+    /// <remarks>
+    /// <para>
+    /// When used with function calling middleware, this does not affect the ability to perform multiple function calls in sequence.
+    /// It only affects the number of function calls within a single iteration of the function calling loop.
+    /// </para>
+    /// <para>
+    /// The underlying provider is not guaranteed to support or honor this flag. For example it may choose to ignore it and return multiple tool calls regardless.
+    /// </para>
+    /// </remarks>
+    public bool? AllowMultipleToolCalls { get; set; }
+
     /// <summary>Gets or sets the tool mode for the chat request.</summary>
     /// <remarks>The default value is <see langword="null"/>, which is treated the same as <see cref="ChatToolMode.Auto"/>.</remarks>
     public ChatToolMode? ToolMode { get; set; }
@@ -125,6 +142,7 @@ public virtual ChatOptions Clone()
             Seed = Seed,
             ResponseFormat = ResponseFormat,
             ModelId = ModelId,
+            AllowMultipleToolCalls = AllowMultipleToolCalls,
             ToolMode = ToolMode,
             AdditionalProperties = AdditionalProperties?.Clone(),
         };

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

@@ -496,6 +496,7 @@ private static ChatCompletionOptions ToOpenAIOptions(ChatOptions? options)
             result.TopP = options.TopP;
             result.PresencePenalty = options.PresencePenalty;
             result.Temperature = options.Temperature;
+            result.AllowParallelToolCalls = options.AllowMultipleToolCalls;
 #pragma warning disable OPENAI001 // Type is for evaluation purposes only and is subject to change or removal in future updates.
             result.Seed = options.Seed;
 #pragma warning restore OPENAI001
@@ -510,11 +511,6 @@ private static ChatCompletionOptions ToOpenAIOptions(ChatOptions? options)
 
             if (options.AdditionalProperties is { Count: > 0 } additionalProperties)
             {
-                if (additionalProperties.TryGetValue(nameof(result.AllowParallelToolCalls), out bool allowParallelToolCalls))
-                {
-                    result.AllowParallelToolCalls = allowParallelToolCalls;
-                }
-
                 if (additionalProperties.TryGetValue(nameof(result.AudioOptions), out ChatAudioOptions? audioOptions))
                 {
                     result.AudioOptions = audioOptions;

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

@@ -312,15 +312,11 @@ private static ResponseCreationOptions ToOpenAIResponseCreationOptions(ChatOptio
             result.PreviousResponseId = options.ConversationId;
             result.TopP = options.TopP;
             result.Temperature = options.Temperature;
+            result.ParallelToolCallsEnabled = options.AllowMultipleToolCalls;
 
             // Handle loosely-typed properties from AdditionalProperties.
             if (options.AdditionalProperties is { Count: > 0 } additionalProperties)
             {
-                if (additionalProperties.TryGetValue(nameof(result.ParallelToolCallsEnabled), out bool allowParallelToolCalls))
-                {
-                    result.ParallelToolCallsEnabled = allowParallelToolCalls;
-                }
-
                 if (additionalProperties.TryGetValue(nameof(result.EndUserId), out string? endUserId))
                 {
                     result.EndUserId = endUserId;

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/ChatCompletion/ChatOptionsTests.cs

@@ -24,22 +24,24 @@ public void Constructor_Parameterless_PropsDefaulted()
         Assert.Null(options.ResponseFormat);
         Assert.Null(options.ModelId);
         Assert.Null(options.StopSequences);
+        Assert.Null(options.AllowMultipleToolCalls);
         Assert.Null(options.ToolMode);
         Assert.Null(options.Tools);
         Assert.Null(options.AdditionalProperties);
 
         ChatOptions clone = options.Clone();
-        Assert.Null(options.ConversationId);
+        Assert.Null(clone.ConversationId);
         Assert.Null(clone.Temperature);
         Assert.Null(clone.MaxOutputTokens);
         Assert.Null(clone.TopP);
         Assert.Null(clone.TopK);
         Assert.Null(clone.FrequencyPenalty);
         Assert.Null(clone.PresencePenalty);
-        Assert.Null(options.Seed);
+        Assert.Null(clone.Seed);
         Assert.Null(clone.ResponseFormat);
         Assert.Null(clone.ModelId);
         Assert.Null(clone.StopSequences);
+        Assert.Null(clone.AllowMultipleToolCalls);
         Assert.Null(clone.ToolMode);
         Assert.Null(clone.Tools);
         Assert.Null(clone.AdditionalProperties);
@@ -78,6 +80,7 @@ public void Properties_Roundtrip()
         options.ResponseFormat = ChatResponseFormat.Json;
         options.ModelId = "modelId";
         options.StopSequences = stopSequences;
+        options.AllowMultipleToolCalls = true;
         options.ToolMode = ChatToolMode.RequireAny;
         options.Tools = tools;
         options.AdditionalProperties = additionalProps;
@@ -93,22 +96,24 @@ public void Properties_Roundtrip()
         Assert.Same(ChatResponseFormat.Json, options.ResponseFormat);
         Assert.Equal("modelId", options.ModelId);
         Assert.Same(stopSequences, options.StopSequences);
+        Assert.True(options.AllowMultipleToolCalls);
         Assert.Same(ChatToolMode.RequireAny, options.ToolMode);
         Assert.Same(tools, options.Tools);
         Assert.Same(additionalProps, options.AdditionalProperties);
 
         ChatOptions clone = options.Clone();
-        Assert.Equal("12345", options.ConversationId);
+        Assert.Equal("12345", clone.ConversationId);
         Assert.Equal(0.1f, clone.Temperature);
         Assert.Equal(2, clone.MaxOutputTokens);
         Assert.Equal(0.3f, clone.TopP);
         Assert.Equal(42, clone.TopK);
         Assert.Equal(0.4f, clone.FrequencyPenalty);
         Assert.Equal(0.5f, clone.PresencePenalty);
-        Assert.Equal(12345, options.Seed);
+        Assert.Equal(12345, clone.Seed);
         Assert.Same(ChatResponseFormat.Json, clone.ResponseFormat);
         Assert.Equal("modelId", clone.ModelId);
         Assert.Equal(stopSequences, clone.StopSequences);
+        Assert.True(clone.AllowMultipleToolCalls);
         Assert.Same(ChatToolMode.RequireAny, clone.ToolMode);
         Assert.Equal(tools, clone.Tools);
         Assert.Equal(additionalProps, clone.AdditionalProperties);
@@ -141,6 +146,7 @@ public void JsonSerialization_Roundtrips()
         options.ResponseFormat = ChatResponseFormat.Json;
         options.ModelId = "modelId";
         options.StopSequences = stopSequences;
+        options.AllowMultipleToolCalls = false;
         options.ToolMode = ChatToolMode.RequireAny;
         options.Tools =
         [
@@ -166,6 +172,7 @@ public void JsonSerialization_Roundtrips()
         Assert.Equal("modelId", deserialized.ModelId);
         Assert.NotSame(stopSequences, deserialized.StopSequences);
         Assert.Equal(stopSequences, deserialized.StopSequences);
+        Assert.False(deserialized.AllowMultipleToolCalls);
         Assert.Equal(ChatToolMode.RequireAny, deserialized.ToolMode);
         Assert.Null(deserialized.Tools);
 

test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIChatClientTests.cs

@@ -319,6 +319,7 @@ public async Task NonStronglyTypedOptions_AllSent()
 
         Assert.NotNull(await client.GetResponseAsync("hello", new()
         {
+            AllowMultipleToolCalls = false,
             AdditionalProperties = new()
             {
                 ["StoredOutputEnabled"] = true,
@@ -329,7 +330,6 @@ public async Task NonStronglyTypedOptions_AllSent()
                 ["LogitBiases"] = new Dictionary<int, int> { { 12, 34 } },
                 ["IncludeLogProbabilities"] = true,
                 ["TopLogProbabilityCount"] = 42,
-                ["AllowParallelToolCalls"] = false,
                 ["EndUserId"] = "12345",
             },
         }));