Add support for workflow events to OAI responses impl

Author: ReubenBond

dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/EndpointRouteBuilderExtensions.Responses.cs

@@ -2,8 +2,6 @@
 
 using System;
 using System.Diagnostics.CodeAnalysis;
-using System.IO;
-using System.Text.Json;
 using System.Threading;
 using Microsoft.Agents.AI;
 using Microsoft.Agents.AI.Hosting.OpenAI.Responses;

dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/Responses/AIAgentResponsesProcessor.cs

@@ -4,7 +4,6 @@
 using System.Linq;
 using System.Net.ServerSentEvents;
 using System.Text.Json;
-using System.Text.Json.Serialization;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Agents.AI.Hosting.OpenAI.Responses.Models;

dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/Responses/AgentRunResponseUpdateExtensions.cs

@@ -4,11 +4,13 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Runtime.CompilerServices;
+using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Agents.AI.Hosting.OpenAI.Responses.Converters;
 using Microsoft.Agents.AI.Hosting.OpenAI.Responses.Models;
 using Microsoft.Agents.AI.Hosting.OpenAI.Responses.Streaming;
+using Microsoft.Agents.AI.Workflows;
 using Microsoft.Extensions.AI;
 
 namespace Microsoft.Agents.AI.Hosting.OpenAI.Responses;
@@ -50,6 +52,13 @@ internal static async IAsyncEnumerable<StreamingResponseEvent> ToStreamingRespon
             cancellationToken.ThrowIfCancellationRequested();
             var update = updateEnumerator.Current;
 
+            // Special-case for agent framework workflow events.
+            if (update.RawRepresentation is WorkflowEvent workflowEvent)
+            {
+                yield return CreateWorkflowEventResponse(workflowEvent, seq.Increment(), outputIndex);
+                continue;
+            }
+
             if (!IsSameMessage(update, previousUpdate))
             {
                 // Finalize the current generator when moving to a new message.
@@ -192,4 +201,47 @@ static bool IsSameValue(string? str1, string? str2) =>
         static bool IsSameRole(ChatRole? value1, ChatRole? value2) =>
             !value1.HasValue || !value2.HasValue || value1.Value == value2.Value;
     }
+
+    private static StreamingWorkflowEventComplete CreateWorkflowEventResponse(WorkflowEvent workflowEvent, int sequenceNumber, int outputIndex)
+    {
+        // Extract executor_id if this is an ExecutorEvent
+        string? executorId = null;
+        if (workflowEvent is ExecutorEvent execEvent)
+        {
+            executorId = execEvent.ExecutorId;
+        }
+        JsonElement eventData;
+        if (JsonSerializer.IsReflectionEnabledByDefault)
+        {
+            var eventDataDict = new Dictionary<string, object?>
+            {
+                ["event_type"] = workflowEvent.GetType().Name,
+                ["data"] = workflowEvent.Data,
+                ["executor_id"] = executorId,
+                ["timestamp"] = DateTime.UtcNow.ToString("O")
+            };
+
+#pragma warning disable IL2026 // Members annotated with 'RequiresUnreferencedCodeAttribute' require dynamic access otherwise can break functionality when trimming application code
+#pragma warning disable IL3050 // Calling members annotated with 'RequiresDynamicCodeAttribute' may break functionality when AOT compiling.
+            eventData = JsonSerializer.SerializeToElement(eventDataDict, ResponsesJsonSerializerOptions.Default);
+#pragma warning restore IL3050 // Calling members annotated with 'RequiresDynamicCodeAttribute' may break functionality when AOT compiling.
+#pragma warning restore IL2026 // Members annotated with 'RequiresUnreferencedCodeAttribute' require dynamic access otherwise can break functionality when trimming application code
+        }
+        else
+        {
+            eventData = JsonSerializer.SerializeToElement(
+                "Unsupported. Workflow event serialization is currently only supported when JsonSerializer.IsReflectionEnabledByDefault is true.",
+                ResponsesJsonContext.Default.String);
+        }
+
+        // Create the properly typed streaming workflow event
+        return new StreamingWorkflowEventComplete
+        {
+            SequenceNumber = sequenceNumber,
+            OutputIndex = outputIndex,
+            Data = eventData,
+            ExecutorId = executorId,
+            ItemId = $"wf_{Guid.NewGuid().ToString("N")[..8]}"
+        };
+    }
 }

dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/Responses/Models/StreamingResponseEvent.cs

@@ -26,6 +26,7 @@ namespace Microsoft.Agents.AI.Hosting.OpenAI.Responses.Models;
 [JsonDerivedType(typeof(StreamingFunctionCallArgumentsDone), StreamingFunctionCallArgumentsDone.EventType)]
 [JsonDerivedType(typeof(StreamingReasoningSummaryTextDelta), StreamingReasoningSummaryTextDelta.EventType)]
 [JsonDerivedType(typeof(StreamingReasoningSummaryTextDone), StreamingReasoningSummaryTextDone.EventType)]
+[JsonDerivedType(typeof(StreamingWorkflowEventComplete), StreamingWorkflowEventComplete.EventType)]
 internal abstract record StreamingResponseEvent
 {
     /// <summary>
@@ -517,3 +518,44 @@ internal sealed record StreamingReasoningSummaryTextDone : StreamingResponseEven
     [JsonPropertyName("text")]
     public required string Text { get; init; }
 }
+
+/// <summary>
+/// Represents a streaming response event containing a workflow event.
+/// This event is sent during workflow execution to provide observability into workflow steps,
+/// executor invocations, errors, and other workflow lifecycle events.
+/// </summary>
+internal sealed record StreamingWorkflowEventComplete : StreamingResponseEvent
+{
+    /// <summary>
+    /// The constant event type identifier for workflow event events.
+    /// </summary>
+    public const string EventType = "response.workflow_event.complete";
+
+    /// <inheritdoc/>
+    [JsonIgnore]
+    public override string Type => EventType;
+
+    /// <summary>
+    /// Gets or sets the index of the output in the response.
+    /// </summary>
+    [JsonPropertyName("output_index")]
+    public int OutputIndex { get; set; }
+
+    /// <summary>
+    /// Gets or sets the workflow event data containing event type, executor ID, and event-specific data.
+    /// </summary>
+    [JsonPropertyName("data")]
+    public JsonElement? Data { get; set; }
+
+    /// <summary>
+    /// Gets or sets the executor ID if this is an executor-scoped event.
+    /// </summary>
+    [JsonPropertyName("executor_id")]
+    public string? ExecutorId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the item ID for tracking purposes.
+    /// </summary>
+    [JsonPropertyName("item_id")]
+    public string? ItemId { get; set; }
+}

dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/Responses/ResponsesJsonContext.cs

@@ -30,6 +30,7 @@ namespace Microsoft.Agents.AI.Hosting.OpenAI.Responses;
 [JsonSerializable(typeof(StreamingOutputTextDone))]
 [JsonSerializable(typeof(StreamingFunctionCallArgumentsDelta))]
 [JsonSerializable(typeof(StreamingFunctionCallArgumentsDone))]
+[JsonSerializable(typeof(StreamingWorkflowEventComplete))]
 [JsonSerializable(typeof(ReasoningOptions))]
 [JsonSerializable(typeof(ResponseUsage))]
 [JsonSerializable(typeof(ResponseError))]