.NET: Approval requests handling in workflows

[jozkee]

I couldn't find a way to handle user input requests (human in the loop) in the workflow event loop. I was expecting this could be as simple as just type checking for a type extending WorkflowEvent but I don't see one being returned.

If I just let the loop run, I see an ExecutorFailedEvent with the error:

[Event: ExecutorFailedEvent(Executor = 4c39304655fc445bbee8b75ab7d09ca9, Data: System.InvalidOperationException = System.InvalidOperationException: FunctionApprovalRequestContent found with FunctionCall.CallId(s) 'call_tzJTA2K8mNGedRAc4aSjDxst' that have no matching FunctionApprovalResponseContent.

I tried to send the approval response with TrySendMessageAsync but it didn't reach the IChatClient, aditionally, in a non-streaming case, this is not available. I'm not sure if I'm missing a piece in the puzzle but I think it should have a better UX if that's the case.

using Microsoft.Extensions.AI;
using Microsoft.Agents.AI;
using Microsoft.Agents.AI.Workflows;
using Azure.Identity;
using Azure.AI.OpenAI;
#pragma warning disable OPENAI001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
#pragma warning disable MEAI001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.

var endpoint = "https://<my-endpoint>.openai.azure.com";
var deploymentName = "gpt-4o-mini";
IChatClient client = new AzureOpenAIClient(new Uri(endpoint), new AzureCliCredential())
    .GetOpenAIResponseClient(deploymentName)
    .AsIChatClient();

AIAgent agentA = new ChatClientAgent(client, options:
    new ChatClientAgentOptions
    {
        ChatOptions = new ChatOptions
        {
            Tools = [new HostedMcpServerTool("deep-wiki", "https://mcp.deepwiki.com/sse")
            {
                // hosted MCP requires tool approval by default,
                // uncommenting this would workaround the approval shortcoming
                // but that's not the point of the sample
                // ApprovalMode = HostedMcpServerToolApprovalMode.NeverRequire
            },
            // Similarly, using below line would avoid approval requirement for client functions.
            //AIFunctionFactory.Create((object e) => $"Echo {e}", "echo_tool")
            new ApprovalRequiredAIFunction(AIFunctionFactory.Create((object e) => $"Echo {e}", "echo_tool")),
        ]},
        Instructions = "Use your tools to address user petitions, truncate the response to 20 words."
    });

AIAgent agentB = new ChatClientAgent(client, options:
    new ChatClientAgentOptions
    {
        Instructions = "You are an expert translator, translate the input text to Spanish and only the text provided, truncate the response to 20 words."
    });

WorkflowBuilder builder = new(agentA);
builder.AddEdge(agentA, agentB);
Workflow workflow = builder.Build();

await using StreamingRun run = await InProcessExecution.StreamAsync(workflow,
    new List<ChatMessage> { new ChatMessage(ChatRole.User,
    "Use the echo_tool to echo the value 42") });
//"Where's the README file for Microsoft.Extensions.AI package located in the dotnet/extensions repository?") }); // for MCP testing

await run.TrySendMessageAsync(new TurnToken(emitEvents: true));
await foreach (WorkflowEvent evt in run.WatchStreamAsync())
{
    Console.WriteLine($"[Event: {evt}]");
    if (evt is AgentRunUpdateEvent runUpd)
    {
        foreach (var userInputRequest in runUpd.Update.UserInputRequests)
        {
            Console.WriteLine($"Approval request id: {userInputRequest.Id}");
            if (userInputRequest is FunctionApprovalRequestContent farc)
            {
                // Create the approval response
                FunctionApprovalResponseContent response = farc.CreateResponse(approved: true);
                await run.TrySendMessageAsync(new ChatMessage(ChatRole.User, [response])); // didn't work.
            }
            else
            {
                // Handle MCP approval request
            }
        }
    }
}

Console.WriteLine("Done.");

cc @lokitoth @westey-m @stephentoub @jeffhandley

Related: #938, although that issue focuses on orchestration (AgentWorkflowBuilder).

[alliscode]

Thanks for filing this @jozkee. You're not missing anything; this is a known issue. Adding this as a sub-issue to #1982

[markwallace-microsoft]

@jozkee, friendly reminder — this issue is waiting on your response. Please share any updates when you get a chance. (This is an automated message.)