Add InvocationRequired property to FunctionCallContent

src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/FunctionCallContent.cs

@@ -56,6 +56,16 @@ public FunctionCallContent(string callId, string name, IDictionary<string, objec
     [JsonIgnore]
     public Exception? Exception { get; set; }
 
+    /// <summary>
+    /// Gets or sets a value indicating whether this function call requires invocation.
+    /// </summary>
+    /// <remarks>
+    /// This property defaults to <see langword="true"/>, indicating that the function call should be processed.
+    /// When set to <see langword="false"/>, it indicates that the function has already been processed and
+    /// should be ignored by components that process function calls.
+    /// </remarks>
+    public bool InvocationRequired { get; set; } = true;
+
     /// <summary>
     /// Creates a new instance of <see cref="FunctionCallContent"/> parsing arguments using a specified encoding and parser.
     /// </summary>

src/Libraries/Microsoft.Extensions.AI.Abstractions/Microsoft.Extensions.AI.Abstractions.json

@@ -1805,6 +1805,10 @@
           "Member": "System.Exception? Microsoft.Extensions.AI.FunctionCallContent.Exception { get; set; }",
           "Stage": "Stable"
         },
+        {
+          "Member": "bool Microsoft.Extensions.AI.FunctionCallContent.InvocationRequired { get; set; }",
+          "Stage": "Experimental"
+        },
         {
           "Member": "string Microsoft.Extensions.AI.FunctionCallContent.Name { get; }",
           "Stage": "Stable"

src/Libraries/Microsoft.Extensions.AI/ChatCompletion/FunctionInvokingChatClient.cs

@@ -775,7 +775,7 @@ private static bool CopyFunctionCalls(
         int count = content.Count;
         for (int i = 0; i < count; i++)
         {
-            if (content[i] is FunctionCallContent functionCall)
+            if (content[i] is FunctionCallContent functionCall && functionCall.InvocationRequired)
             {
                 (functionCalls ??= []).Add(functionCall);
                 any = true;
@@ -1018,6 +1018,9 @@ private async Task<FunctionInvocationResult> ProcessFunctionCallAsync(
     {
         var callContent = callContents[functionCallIndex];
 
+        // Mark the function call as no longer requiring invocation since we're handling it
+        callContent.InvocationRequired = false;
+
         // Look up the AIFunction for the function call. If the requested function isn't available, send back an error.
         if (toolMap is null ||
             !toolMap.TryGetValue(callContent.Name, out AITool? tool) ||
@@ -1107,6 +1110,9 @@ FunctionResultContent CreateFunctionResultContent(FunctionInvocationResult resul
                 functionResult = message;
             }
 
+            // Mark the function call as having been processed
+            result.CallContent.InvocationRequired = false;
+
             return new FunctionResultContent(result.CallContent.CallId, functionResult) { Exception = result.Exception };
         }
     }
@@ -1416,10 +1422,20 @@ private static (List<ApprovalResultWithRequestMessage>? approvals, List<Approval
     /// </summary>
     /// <param name="rejections">Any rejected approval responses.</param>
     /// <returns>The <see cref="AIContent"/> for the rejected function calls.</returns>
-    private static List<AIContent>? GenerateRejectedFunctionResults(List<ApprovalResultWithRequestMessage>? rejections) =>
-        rejections is { Count: > 0 } ?
-            rejections.ConvertAll(static m => (AIContent)new FunctionResultContent(m.Response.FunctionCall.CallId, "Error: Tool call invocation was rejected by user.")) :
-            null;
+    private static List<AIContent>? GenerateRejectedFunctionResults(List<ApprovalResultWithRequestMessage>? rejections)
+    {
+        if (rejections is not { Count: > 0 })
+        {
+            return null;
+        }
+
+        return rejections.ConvertAll(static m =>
+        {
+            // Mark the function call as no longer requiring invocation since we're handling it (by rejecting it)
+            m.Response.FunctionCall.InvocationRequired = false;
+            return (AIContent)new FunctionResultContent(m.Response.FunctionCall.CallId, "Error: Tool call invocation was rejected by user.");
+        });
+    }
 
     /// <summary>
     /// Extracts the <see cref="FunctionCallContent"/> from the provided <see cref="FunctionApprovalResponseContent"/> to recreate the original function call messages.

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionCallContentTests.cs

@@ -71,6 +71,152 @@ public void Constructor_PropsRoundtrip()
         Exception e = new();
         c.Exception = e;
         Assert.Same(e, c.Exception);
+
+        Assert.True(c.InvocationRequired);
+        c.InvocationRequired = false;
+        Assert.False(c.InvocationRequired);
+    }
+
+    [Fact]
+    public void InvocationRequired_DefaultsToTrue()
+    {
+        FunctionCallContent c = new("callId1", "name");
+        Assert.True(c.InvocationRequired);
+    }
+
+    [Fact]
+    public void InvocationRequired_CanBeSetToFalse()
+    {
+        FunctionCallContent c = new("callId1", "name") { InvocationRequired = false };
+        Assert.False(c.InvocationRequired);
+    }
+
+    [Fact]
+    public void InvocationRequired_SerializedWhenFalse()
+    {
+        // Arrange - Set InvocationRequired to false (to allow roundtrip, it must be serialized even when false)
+        var sut = new FunctionCallContent("callId1", "functionName", new Dictionary<string, object?> { ["key"] = "value" })
+        {
+            InvocationRequired = false
+        };
+
+        // Act
+        var json = JsonSerializer.SerializeToNode(sut, TestJsonSerializerContext.Default.Options);
+
+        // Assert - InvocationRequired should be in the JSON when it's false to allow roundtrip
+        Assert.NotNull(json);
+        var jsonObj = json!.AsObject();
+        Assert.True(jsonObj.ContainsKey("invocationRequired") || jsonObj.ContainsKey("InvocationRequired"));
+
+        JsonNode? invocationRequiredValue = null;
+        if (jsonObj.TryGetPropertyValue("invocationRequired", out var value1))
+        {
+            invocationRequiredValue = value1;
+        }
+        else if (jsonObj.TryGetPropertyValue("InvocationRequired", out var value2))
+        {
+            invocationRequiredValue = value2;
+        }
+
+        Assert.NotNull(invocationRequiredValue);
+        Assert.False(invocationRequiredValue!.GetValue<bool>());
+    }
+
+    [Fact]
+    public void InvocationRequired_SerializedWhenTrue()
+    {
+        // Arrange - InvocationRequired defaults to true
+        var sut = new FunctionCallContent("callId1", "functionName", new Dictionary<string, object?> { ["key"] = "value" });
+
+        // Act
+        var json = JsonSerializer.SerializeToNode(sut, TestJsonSerializerContext.Default.Options);
+
+        // Assert - InvocationRequired should be in the JSON when it's true
+        Assert.NotNull(json);
+        var jsonObj = json!.AsObject();
+        Assert.True(jsonObj.ContainsKey("invocationRequired") || jsonObj.ContainsKey("InvocationRequired"));
+
+        JsonNode? invocationRequiredValue = null;
+        if (jsonObj.TryGetPropertyValue("invocationRequired", out var value1))
+        {
+            invocationRequiredValue = value1;
+        }
+        else if (jsonObj.TryGetPropertyValue("InvocationRequired", out var value2))
+        {
+            invocationRequiredValue = value2;
+        }
+
+        Assert.NotNull(invocationRequiredValue);
+        Assert.True(invocationRequiredValue!.GetValue<bool>());
+    }
+
+    [Fact]
+    public void InvocationRequired_DeserializedCorrectlyWhenTrue()
+    {
+        // Test deserialization when InvocationRequired is true
+        var json = """{"callId":"callId1","name":"functionName","invocationRequired":true}""";
+        var deserialized = JsonSerializer.Deserialize<FunctionCallContent>(json, TestJsonSerializerContext.Default.Options);
+
+        Assert.NotNull(deserialized);
+        Assert.Equal("callId1", deserialized.CallId);
+        Assert.Equal("functionName", deserialized.Name);
+        Assert.True(deserialized.InvocationRequired);
+    }
+
+    [Fact]
+    public void InvocationRequired_DeserializedCorrectlyWhenFalse()
+    {
+        // Test deserialization when InvocationRequired is false
+        var json = """{"callId":"callId1","name":"functionName","invocationRequired":false}""";
+        var deserialized = JsonSerializer.Deserialize<FunctionCallContent>(json, TestJsonSerializerContext.Default.Options);
+
+        Assert.NotNull(deserialized);
+        Assert.Equal("callId1", deserialized.CallId);
+        Assert.Equal("functionName", deserialized.Name);
+        Assert.False(deserialized.InvocationRequired);
+    }
+
+    [Fact]
+    public void InvocationRequired_DeserializedToTrueWhenMissing()
+    {
+        // Test deserialization when InvocationRequired is not in JSON (should default to true from field initializer)
+        var json = """{"callId":"callId1","name":"functionName"}""";
+        var deserialized = JsonSerializer.Deserialize<FunctionCallContent>(json, TestJsonSerializerContext.Default.Options);
+
+        Assert.NotNull(deserialized);
+        Assert.Equal("callId1", deserialized.CallId);
+        Assert.Equal("functionName", deserialized.Name);
+        Assert.True(deserialized.InvocationRequired);
+    }
+
+    [Fact]
+    public void InvocationRequired_RoundtripTrue()
+    {
+        // Test that InvocationRequired=true roundtrips correctly through JSON serialization
+        var original = new FunctionCallContent("callId1", "functionName") { InvocationRequired = true };
+        var json = JsonSerializer.SerializeToNode(original, TestJsonSerializerContext.Default.Options);
+        var deserialized = JsonSerializer.Deserialize<FunctionCallContent>(json, TestJsonSerializerContext.Default.Options);
+
+        Assert.NotNull(deserialized);
+        Assert.Equal(original.CallId, deserialized.CallId);
+        Assert.Equal(original.Name, deserialized.Name);
+        Assert.Equal(original.InvocationRequired, deserialized.InvocationRequired);
+        Assert.True(deserialized.InvocationRequired);
+    }
+
+    [Fact]
+    public void InvocationRequired_RoundtripFalse()
+    {
+        // Test that InvocationRequired=false roundtrips correctly through JSON serialization
+        var original = new FunctionCallContent("callId1", "functionName") { InvocationRequired = false };
+        var json = JsonSerializer.SerializeToNode(original, TestJsonSerializerContext.Default.Options);
+        var deserialized = JsonSerializer.Deserialize<FunctionCallContent>(json, TestJsonSerializerContext.Default.Options);
+
+        Assert.NotNull(deserialized);
+        Assert.Equal(original.CallId, deserialized.CallId);
+        Assert.Equal(original.Name, deserialized.Name);
+        Assert.Equal(original.InvocationRequired, deserialized.InvocationRequired);
+        Assert.False(deserialized.InvocationRequired);
     }
 
     [Fact]