Using IChatClient with stateless openai responses api

[alientourist]

Hi! I am trying to get a stateless openai client up and running using Microsoft.Extensions.AI. So I am looking for examples of a multi-turn conversation where the returned encrypted reasoning tokens are resent to openai to continue an ongoing conversation.

I am interested in both non-streaming and streaming use cases.

Non-streaming
So in the following trivial non-streaming example I would like to know how to construct the assistant message correctly to include the encrypted reasoning tokens.

            IChatClient client = new OpenAIClient(<key>).GetResponsesClient("gpt-5.2").AsIChatClient();

            var chatOptions = new ChatOptions
            {
                RawRepresentationFactory = _ => new CreateResponseOptions
                {
                    ReasoningOptions = new ResponseReasoningOptions
                    {
                        ReasoningEffortLevel = ResponseReasoningEffortLevel.Low,
                        ReasoningSummaryVerbosity = ResponseReasoningSummaryVerbosity.Concise
                    },
                    StoredOutputEnabled = false,
                    IncludedProperties = { IncludedResponseProperty.ReasoningEncryptedContent },
                },
                
            };
            
            var loggerFactory = LoggerFactory.Create(services => services.AddConsole().SetMinimumLevel(LogLevel.Trace));

            client =
                new ChatClientBuilder(client)
                .UseLogging(loggerFactory)
                .Build();

            List<ChatMessage> chatHistory = new List<ChatMessage>();
            chatHistory.Add(new ChatMessage(ChatRole.System, systemMessage));
            chatHistory.Add(new ChatMessage(ChatRole.User, userMessage));

            ChatResponse response = await client.GetResponseAsync(chatHistory, chatOptions);
			
            // FIGURE OUT HOW TODO THIS
            // Currently this will not include the returned encrypted reasoning items in the next conversation round
            chatHistory.Add(new Microsoft.Extensions.AI.ChatMessage(ChatRole.Assistant, response.Text));

Streaming
And in the streaming case the same question arises since the AddMessages extensions does not seem to include this data

           IChatClient client = new OpenAIClient(<key>).GetResponsesClient("gpt-5.2").AsIChatClient();

           var chatOptions = new ChatOptions
           {
               RawRepresentationFactory = _ => new CreateResponseOptions
               {
                   ReasoningOptions = new ResponseReasoningOptions
                   {
                       ReasoningEffortLevel = ResponseReasoningEffortLevel.Medium,
                       ReasoningSummaryVerbosity = ResponseReasoningSummaryVerbosity.Concise
                   },
                   StoredOutputEnabled = false,
                   IncludedProperties = { IncludedResponseProperty.ReasoningEncryptedContent },
               },
           };

           List<Microsoft.Extensions.AI.ChatMessage> chatHistory = new List<Microsoft.Extensions.AI.ChatMessage>();
           chatHistory.Add(new Microsoft.Extensions.AI.ChatMessage(ChatRole.System, systemMessage));
           chatHistory.Add(new Microsoft.Extensions.AI.ChatMessage(ChatRole.User, userMessage));

           List<ChatResponseUpdate> updates = new List<ChatResponseUpdate>();
           await foreach (ChatResponseUpdate chatResponseUpdate in client.GetStreamingResponseAsync(chatHistory, chatOptions))
           {
               updates.Add(chatResponseUpdate);

               foreach (AIContent aiContent in chatResponseUpdate.Contents)
               { 
                   if (aiContent is TextContent textContent)
                   {
                       Console.Write(textContent);
                   }
                   else if (aiContent is TextReasoningContent textReasoningContent)
                   {
                       Console.Write(textReasoningContent);
                   }
               }
           }

           // FIGURE OUT HOW TODO THIS
           // Currently this does not include the returned encrypted reasoning items
           chatHistory.AddMessages(updates);

Any information about how to do this or even if its possible using Microsoft.Extensions.AI would be appreciated!

Best regards,
Andreas

[stephentoub]

        // FIGURE OUT HOW TODO THIS
       // Currently this will not include the returned encrypted reasoning items in the next conversation round
       chatHistory.Add(new Microsoft.Extensions.AI.ChatMessage(ChatRole.Assistant, response.Text));

For non-streaming, you should be able to do:

chatHistory.AddMessages(response);

or:

chatHistory.AddRange(response.Messages);

Does that not work? I expect it would.

// Currently this does not include the returned encrypted reasoning items

For streaming, it looks like we currently have a bug in how ReasoningResponseItems are handled. I'll put up a PR to fix it.