openai/openai-dotnet

using NUnit.Framework;
using OpenAI.Responses;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.Json;
using System.Threading.Tasks;

namespace OpenAI.Examples;

// This example uses experimental APIs which are subject to change. To use experimental APIs,
// please acknowledge their experimental status by suppressing the corresponding warning.
#pragma warning disable OPENAI001

public partial class ResponseExamples
{
    // See Example03_FunctionCalling.cs for the tool and function definitions.

    [Test]
    public async Task Example03_FunctionCallingAsync()
    {
        ResponsesClient client = new(apiKey: Environment.GetEnvironmentVariable("OPENAI_API_KEY"));

        List<ResponseItem> inputItems =
        [
            ResponseItem.CreateUserMessageItem("What's the weather like today for my current location?"),
        ];

        PrintMessageItems(inputItems.OfType<MessageResponseItem>());

        bool requiresAction;

        do
        {
            requiresAction = false;

            CreateResponseOptions options = new("gpt-5", inputItems)
            {
                Tools = { getCurrentLocationTool, getCurrentWeatherTool },
            };

            ResponseResult response = await client.CreateResponseAsync(options);

            inputItems.AddRange(response.OutputItems);

            foreach (ResponseItem outputItem in response.OutputItems)
            {
                if (outputItem is FunctionCallResponseItem functionCall)
                {
                    switch (functionCall.FunctionName)
                    {
                        case nameof(GetCurrentLocation):
                            {
                                string functionOutput = GetCurrentLocation();
                                inputItems.Add(new FunctionCallOutputResponseItem(functionCall.CallId, functionOutput));
                                break;
                            }

                        case nameof(GetCurrentWeather):
                            {
                                // The arguments that the model wants to use to call the function are specified as a
                                // stringified JSON object based on the schema defined in the tool definition. Note that
                                // the model may hallucinate arguments too. Consequently, it is important to do the
                                // appropriate parsing and validation before calling the function.
                                using JsonDocument argumentsJson = JsonDocument.Parse(functionCall.FunctionArguments);
                                bool hasLocation = argumentsJson.RootElement.TryGetProperty("location", out JsonElement location);
                                bool hasUnit = argumentsJson.RootElement.TryGetProperty("unit", out JsonElement unit);

                                if (!hasLocation)
                                {
                                    throw new ArgumentNullException(nameof(location), "The location argument is required.");
                                }

                                string functionOutput = hasUnit
                                    ? GetCurrentWeather(location.GetString(), unit.GetString())
                                    : GetCurrentWeather(location.GetString());
                                inputItems.Add(new FunctionCallOutputResponseItem(functionCall.CallId, functionOutput));
                                break;
                            }

                        default:
                            {
                                // Handle other unexpected calls.
                                throw new NotImplementedException();
                            }
                    }

                    requiresAction = true;
                    break;
                }
            }

            PrintMessageItems(response.OutputItems.OfType<MessageResponseItem>());

        } while (requiresAction);
    }
}

#pragma warning restore OPENAI001