C# - Foundry Local을 이용한 gpt-oss-20b 모델 사용

오호~~~ 최근 OpenAI에서 GPT OSS 20B 모델을 공개했는데요, Hugging Face에도 올라온 상태입니다.

openai/gpt-oss-20b
; https://huggingface.co/openai/gpt-oss-20b/blob/main/config.json

Available today: gpt-oss-20B Model on Windows with GPU Acceleration – further pushing the boundaries on the edge
; https://blogs.windows.com/windowsdeveloper/2025/08/05/available-today-gpt-oss-20b-model-on-windows-with-gpu-acceleration-further-pushing-the-boundaries-on-the-edge/

Windows + Foundry Local - 로컬에서 AI 모델 활용
; https://www.sysnet.pe.kr/2/0/13943

C:\temp> foundry model download gpt-oss-20B
Downloading gpt-oss-20b-cuda-gpu...
[####################################] 100.00 % [Time remaining: about 0s]        36.9 MB/s
Tips:
- To find model cache location use: foundry cache location
- To find models already downloaded use: foundry cache ls

using OpenAI;
using OpenAI.Chat;
using System.ClientModel;

namespace ConsoleApp1;

internal class Program
{
    // Install-Package OpenAI 
    static void Main(string[] args)
    {
        string ep = "http://localhost:5273/v1";
        string key = "OPENAI_API_KEY";
        string alias = "gpt-oss-20b-cuda-gpu";

        OpenAIClientOptions options = new OpenAIClientOptions();
        options.Endpoint = new Uri(ep);

        ApiKeyCredential akc = new ApiKeyCredential(key);
        ChatClient client = new(alias, akc, options);

        ChatCompletion completion = client.CompleteChat("하늘이 파란 이유는?'");

        foreach (var message in completion.Content)
        {
            Console.WriteLine($"[{message.Kind}]: {message.Text}");
        }
    }
}

/* 실행 결과:

[Text]: <|channel|>analysis<|message|>The user says: "하늘이 파란 이유는?" in Korean, which translates to "The reason why the sky is blue?" The question is likely about the reason behind Rayleigh scattering, color of sky because of scattering of shorter wavelengths of visible light off atmosphere, etc.

We need to respond. The user didn't give any context besides asking. They just say in Korean: "The reason the sky is blue?" So answer: It's due to Rayleigh scattering causing blue light to be scattered more.

We can provide explanation: solar light: white, but Earth's atmosphere scatters more of blue wavelengths, causing blue sky.

So just answer like: "태양빛이 투과하면서 대기 중 분자와 아주 작은 입자에 의해 산란된 파장에서 가장 짧은 파장이 산란이 가장 잘 일어나므로..." or we can keep simple.

We can also mention the "Huygens–Fresnel principle" or "Mie scattering
*/

using Microsoft.ML.OnnxRuntimeGenAI;
using System.Reflection;
using System.Reflection.Emit;

namespace ConsoleApp2;

internal class Program
{
    // Install-Package Microsoft.ML.OnnxRuntimeGenAI.CUDA

    static void Main(string[] args)
    {
        // cuDNN 필요
        string? path = Environment.GetEnvironmentVariable("PATH");
        path += @";C:\Program Files\NVIDIA\CUDNN\v9.10\bin\12.9";
        Environment.SetEnvironmentVariable("PATH", path);

        string modelPath = @"C:\foundry_cache\Microsoft\gpt-oss-20b-cuda-gpu\v1";

        Console.Write("Loading model from " + modelPath + "...");
        using Model model = new(modelPath);
        Console.Write("Done\n");
        using Tokenizer tokenizer = new(model);
        using TokenizerStream tokenizerStream = tokenizer.CreateStream();

        while (true)
        {
            Console.Write("User:");

            string prompt = "<|im_start|>user\n" +
                            Console.ReadLine() +
                            "<|im_end|>\n<|im_start|>assistant\n";
            var sequences = tokenizer.Encode(prompt);

            using GeneratorParams gParams = new GeneratorParams(model);
            gParams.SetSearchOption("max_length", 2400);
            using Generator generator = new(model, gParams);
            generator.AppendTokenSequences(sequences);

            Console.Out.Write("\nAI:");
            while (!generator.IsDone())
            {
                generator.GenerateNextToken();
                var token = generator.GetSequence(0)[^1];
                Console.Out.Write(tokenizerStream.Decode(token));
                Console.Out.Flush();
            }
            Console.WriteLine();
        }
    }
}

C:\foundry_cache> foundry model run gpt-oss-20B
Exception: Model gpt-oss-20B not found