fix: Duplicate CallIds cause Handoff Message Filtering to fail

Some providers, e.g. Gemini, do not use the CallId mechanism to disambiguate simultaneous function calls. This can result in message lists containing multiple turn to fail to filter properly. The fix is to take advantage of the expectation that Handoff Orchestration is a "single-speaker" flow, which only has a single active AIAgent per "turn" and an agent's turn is not finished until all outstanding function calls are finished. This allows us to expect that any ambiguous-CallId FunctionCallContent are either in separate turns or will have had a response before the next issued call with the same Id.
2026-06-16 21:04:09 +08:00 · 2026-04-20 07:34:09 -04:00
parent 60af59ba8b
commit f082fcbca7
3 changed files with 172 additions and 91 deletions
@@ -0,0 +1,115 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System;
+using System.Collections.Generic;
+using FluentAssertions;
+using Microsoft.Agents.AI.Workflows.Specialized;
+using Microsoft.Extensions.AI;
+
+namespace Microsoft.Agents.AI.Workflows.UnitTests;
+
+public class HandoffMessageFilterTests
+{
+    private List<ChatMessage> CreateTestMessages(bool firstAgentUsesCallId, bool secondAgentUsesCallId, HandoffToolCallFilteringBehavior filter = HandoffToolCallFilteringBehavior.None)
+    {
+        FunctionCallContent handoffRequest1 = CreateHandoffCall(1, firstAgentUsesCallId);
+        FunctionResultContent handoffResponse1 = CreateHandoffResponse(handoffRequest1);
+
+        FunctionCallContent toolCall = CreateToolCall(secondAgentUsesCallId);
+        FunctionResultContent toolResponse = CreateToolResponse(toolCall);
+
+        // Approvals come from the function call middleware over ChatClient, so we can expect there to be a RequestId (not that we
+        // care, because we do not filter approval content)
+        ToolApprovalRequestContent toolApproval = new(Guid.NewGuid().ToString("N"), toolCall);
+        ToolApprovalResponseContent toolApprovalResponse = new(toolApproval.RequestId, true, toolCall);
+
+        FunctionCallContent handoffRequest2 = CreateHandoffCall(1, secondAgentUsesCallId);
+        FunctionResultContent handoffResponse2 = CreateHandoffResponse(handoffRequest2);
+
+        List<ChatMessage> result = [new(ChatRole.User, "Hello")];
+
+        // Agent 1 turn
+        result.Add(new(ChatRole.Assistant, "Hello! What do you want help with today?"));
+        result.Add(new(ChatRole.User, "Please explain temperature"));
+
+        // Unless we are filtering none, we expect the handoff call to be filtered out, so we add it conditionally
+        if (filter == HandoffToolCallFilteringBehavior.None)
+        {
+            result.Add(new(ChatRole.Assistant, [handoffRequest1]));
+            result.Add(new(ChatRole.Tool, [handoffResponse1]));
+        }
+
+        // Agent 2 turn
+
+        // Tool approvals are never filtered, so we add them unconditionally
+        result.Add(new(ChatRole.Assistant, [toolApproval]));
+        result.Add(new(ChatRole.User, [toolApprovalResponse]));
+
+        // Unless we are filtering all, we expect the tool call to be retained, so we add it conditionally
+        if (filter != HandoffToolCallFilteringBehavior.All)
+        {
+            result.Add(new(ChatRole.Assistant, [toolCall]));
+            result.Add(new(ChatRole.Tool, [toolResponse]));
+        }
+
+        result.Add(new(ChatRole.Assistant, "Temperature is a measure of the average kinetic energy of the particles in a substance."));
+
+        if (filter == HandoffToolCallFilteringBehavior.None)
+        {
+            result.Add(new(ChatRole.Assistant, [handoffRequest2]));
+            result.Add(new(ChatRole.Tool, [handoffResponse2]));
+        }
+
+        return result;
+    }
+
+    private static FunctionCallContent CreateHandoffCall(int id, bool useCallId)
+    {
+        string callName = $"{HandoffWorkflowBuilder.FunctionPrefix}{id}";
+        string callId = useCallId ? Guid.NewGuid().ToString("N") : callName;
+
+        return new FunctionCallContent(callId, callName);
+    }
+
+    private static FunctionResultContent CreateHandoffResponse(FunctionCallContent call)
+        => HandoffAgentExecutor.CreateHandoffResult(call.CallId);
+
+    private static FunctionCallContent CreateToolCall(bool useCallId)
+    {
+        const string CallName = "ToolFunction";
+        string callId = useCallId ? Guid.NewGuid().ToString("N") : CallName;
+
+        return new FunctionCallContent(callId, CallName);
+    }
+
+    private static FunctionResultContent CreateToolResponse(FunctionCallContent call)
+        => new(call.CallId, new object());
+
+    [Theory]
+    [InlineData(true, true, HandoffToolCallFilteringBehavior.None)]
+    [InlineData(true, false, HandoffToolCallFilteringBehavior.None)]
+    [InlineData(false, true, HandoffToolCallFilteringBehavior.None)]
+    [InlineData(false, false, HandoffToolCallFilteringBehavior.None)]
+    [InlineData(true, true, HandoffToolCallFilteringBehavior.HandoffOnly)]
+    [InlineData(true, false, HandoffToolCallFilteringBehavior.HandoffOnly)]
+    [InlineData(false, true, HandoffToolCallFilteringBehavior.HandoffOnly)]
+    [InlineData(false, false, HandoffToolCallFilteringBehavior.HandoffOnly)]
+    [InlineData(true, true, HandoffToolCallFilteringBehavior.All)]
+    [InlineData(true, false, HandoffToolCallFilteringBehavior.All)]
+    [InlineData(false, true, HandoffToolCallFilteringBehavior.All)]
+    [InlineData(false, false, HandoffToolCallFilteringBehavior.All)]
+    public void Test_HandoffMessageFilter_FiltersOnlyExpectedMessages(bool firstAgentUsesCallId, bool secondAgentUsesCallId, HandoffToolCallFilteringBehavior behavior)
+    {
+        // Arrange
+        List<ChatMessage> messages = this.CreateTestMessages(firstAgentUsesCallId, secondAgentUsesCallId);
+        List<ChatMessage> expected = this.CreateTestMessages(firstAgentUsesCallId, secondAgentUsesCallId, behavior);
+
+        HandoffMessagesFilter filter = new(behavior);
+
+        // Act
+        IEnumerable<ChatMessage> filteredMessages = filter.FilterMessages(messages);
+
+        // Assert
+        filteredMessages.Should().BeEquivalentTo(expected);
+    }
+}