How to read the reasoning_content with Microsoft.Extensions.AI?

[BenLampson]

I'm writing the deepseek-r1 agent with Microsoft.Extensions.AI, but I can't to read the reasoning_content in the Microsoft.Extensions.AI

There's the api's raw json response.

{
    "choices": [
        {
            "message": {
                "content": "xxxx",
                "reasoning_content": "yyyy",
                "role": "assistant"
            },
            "finish_reason": "stop",
            "index": 0,
            "logprobs": null
        }
    ],
    "object": "chat.completion",
    "usage": {
        "prompt_tokens": 19,
        "completion_tokens": 797,
        "total_tokens": 816
    },
    "created": 1739069910,
    "system_fingerprint": null,
    "model": "deepseek-r1",
    "id": "chatcmpl-e55cdb8a-9ce1-9662-b87c-cf3da706e4f3"
}

There's my code.

     var chatOptions = new ChatOptions
     {
         //ResponseFormat = ChatResponseFormat.Json,
         // response_format neded for their json setup -- https://api-docs.deepseek.com/guides/json_mode
         AdditionalProperties = new AdditionalPropertiesDictionary
         {
             ["reasoning_content"] = new
             {
                 type = "json"
             }
         }
     };

     var res = client.GetStreamingResponseAsync(msgs, chatOptions);

     await foreach (var item in res)
     {
         Console.Write(item.Text);
     }

I can't find anything about the reasoning_content in debug model.

[stephentoub]

What library are you using to access deepseek?

[BenLampson]

I use the "using Microsoft.Extensions.AI;"

There's my complete code, it's the sample demo

using Microsoft.Extensions.AI;
using System.ClientModel;
using System.ComponentModel;

namespace Issues
{
    internal class Program
    {

        static async Task Main(string[] args)
        {

            var opeAiClient = new OpenAI.OpenAIClient(
                       new ApiKeyCredential(Environment.GetEnvironmentVariable("OpenAIKey")!),
                       new OpenAI.OpenAIClientOptions()
                       {
                           Endpoint = new Uri(Environment.GetEnvironmentVariable("OpenAIUri")!)
                       });
            IChatClient chatClient = new OpenAIChatClient(opeAiClient, "deepseek-r1");

            chatClient = new ChatClientBuilder(chatClient).UseFunctionInvocation().Build();

            var tmpToolInstance = new TestTool();

            List<AITool> tools =
                [
                //AIFunctionFactory.Create(tmpToolInstance.Has_Not_Any_Info),
                //    AIFunctionFactory.Create(tmpToolInstance.Update_Collection_Info),
                ];


            var messages = new List<ChatMessage>()
            {
                new(ChatRole.System,@"Attempt to understand user issues and record relevant information.
##Information Content
Number:1
Description: Item Name 

Number:2 
Description: Quantity of items"),
            };



            while (true)
            {
                Console.Write($"\n\n user >>");
                var userMsg = string.Empty;
                while (string.IsNullOrWhiteSpace(userMsg))
                {
                    userMsg = Console.ReadLine();
                }
                messages.Add(new ChatMessage(ChatRole.User, userMsg));


                var aiRes = chatClient.GetStreamingResponseAsync(messages, new ChatOptions()
                {
                    Tools = tools
                });

                await foreach (var chunk in aiRes)
                {
                    Console.Write(chunk.Text);
                }

            }
        }


        public class TestTool
        {
            [Description("If no useful information is collected, this function will not return any information")]
            public void Has_Not_Any_Info()
            {
                Console.WriteLine($"\n\n Call the method Has_Not_Any_Info ");
            }

            [Description("Save a collected information, this function will not return any information")]
            public void Update_Collection_Info([Description("Info number")] int number, [Description("Detail info")] string data)
            {
                Console.WriteLine($"\n\n call the method  Update_Collection_Info number: {number} data: {data}");

            }
        }
    }
}

Today, I think I have found the reason_content.
It's in this place.
But I can't find any way to got them.

It's in the openai SDK.

[stephentoub]

The OpenAI library does not currently expose the ability to access this information.
openai/openai-dotnet#259