.NET: DevUI not starting a conversation (404 error)

[Dazfl]

I have tried to wire up DevUI to my dotnet application but I am getting the following error:

I have a asp.net core web api application. I have configured the chat client as ('openai-chat' is configured in Aspire AppHost):

var openai = builder.AddOpenAIClient("openai-chat")
    .AddChatClient()
    .UseFunctionInvocation()
    .UseOpenTelemetry(configure: c => c.EnableSensitiveData = builder.Environment.IsDevelopment());

and my agent is configured as:

builder.AddAIAgent("VendorAgent", (serviceProvider, key) =>
{
    var chatClient = serviceProvider.GetRequiredService<IChatClient>();

    return new ChatClientAgent(
        chatClient,
        name: "JokeAgent",
        instructions: "You are a world-class dad joke teller. Tell me your best dad joke.",
        services: serviceProvider);
});

DevUI find the agent just fine, I just can't have a conversation with the agent. What else am I missing

[rogeriorfp]

@Dazfl there must be a match between name and key

builder.AddAIAgent("name", (sp, key) => { 
    ...
});

builder.AddAIAgent("VendorAgent", (serviceProvider, key) =>
{
    var chatClient = serviceProvider.GetRequiredService<IChatClient>();

    return new ChatClientAgent(
        chatClient,
        name: "JokeAgent", // Change here to key or "VendorAgent"
        instructions: "You are a world-class dad joke teller. Tell me your best dad joke.",
        services: serviceProvider);
});

[Dazfl]

@rogeriorfp ... I have applied your suggestion, and the error is still appearing.

One thing I forgot to mention, I have also added this to my program.cs file:

app.MapDevUI();

From the demos, there appears to be a builder.Services.AddDevUI(); method somewhere, but I can't seem to find the library this comes from. Has it been removed?

[rogeriorfp]

@rogeriorfp ... I have applied your suggestion, and the error is still appearing.

One thing I forgot to mention, I have also added this to my program.cs file:

app.MapDevUI();

From the demos, there appears to be a builder.Services.AddDevUI(); method somewhere, but I can't seem to find the library this comes from. Has it been removed?

I don't remember the exact version, but yes, the AddDevUI() method has been removed. Instead, you should use builder.AddOpenAIResponses() and builder.AddOpenAIConversations(), as shown in this sample

There is also a Web API project template with DevUI that can be installed using the command dotnet new install Microsoft.Agents.AI.ProjectTemplates. After that, you can create the project with dotnet new aiagent-webapi, or by creating a new project in Visual Studio using the AI Agent Web API template."**

[Dazfl]

@rogeriorfp ... perfect! Adding .AddOpenAIResponse() and .AddOpenAIConversation() worked.

I also added app.MapOpenAIResponse() and app.MapOpenAIConversations(). After that, everything worked.

Thank you so much.

[rogeriorfp]

@rogeriorfp ... perfect! Adding .AddOpenAIResponse() and .AddOpenAIConversation() worked.

I also added app.MapOpenAIResponse() and app.MapOpenAIConversations(). After that, everything worked.

Thank you so much.

Great to hear it worked! Happy to help! 👍

[DeagleGross]

Right, DevUI needs OpenAI Responses to be mapped in your builder, since DevUI communication is handled via OpenAI Responses protocol.

sorry for not published docs on DevUI yet on the official MS page, we only mention that in the samples

Also DevUI has AddDevUI() method on the ServiceCollection / HostApplicationBuilder -> that is reuqired for easier integration.

Let me know if you think there are any actions in this item, closing for now

[Dazfl]

@DeagleGross ... no problems about the docs. It is all working now.

The only thing missing for me is AddDevUI(). As I mentioned earlier, this method appears to be missing, or I haven't added the correct nuget package to my app.

[rogeriorfp]

The AddDevUI method used to be in the class DevUIExtensions
, alongside MapDevUI, but it was moved to the class mentioned by @DeagleGross. However, this change happened after the latest NuGet release, 1.0.0-preview.251114.1.

In other words, it was removed from DevUIExtensions before the last release and added to the new class afterward