Install and instrument

OpenAI

Add the OpenAI integration package

dotnet add package Braintrust.Sdk.OpenAI
dotnet add package OpenAI

Wrap the OpenAI client

Initialize Braintrust, get an ActivitySource, and wrap the client with BraintrustOpenAI.WrapOpenAI. Every call on the wrapped client is traced.

using System;
using System.Threading.Tasks;
using Braintrust.Sdk;
using Braintrust.Sdk.OpenAI;
using OpenAI;
using OpenAI.Chat;

class OpenAITracing
{
    static async Task Main(string[] args)
    {
        var braintrust = Braintrust.Sdk.Braintrust.Get();
        var activitySource = braintrust.GetActivitySource();

        var apiKey = Environment.GetEnvironmentVariable("OPENAI_API_KEY");
        if (string.IsNullOrEmpty(apiKey))
        {
            Console.WriteLine("Error: OPENAI_API_KEY environment variable is not set.");
            return;
        }

        // Wrap the OpenAI client with Braintrust instrumentation
        var client = BraintrustOpenAI.WrapOpenAI(
            activitySource,
            apiKey
        );

        // All API calls are automatically logged
        var chatClient = client.GetChatClient("gpt-4o-mini");
        var messages = new ChatMessage[]
        {
            new SystemChatMessage("You are a helpful assistant."),
            new UserChatMessage("What is machine learning?")
        };

        var result = await chatClient.CompleteChatAsync(messages);
    }
}

Anthropic

Add the Anthropic integration package

dotnet add package Braintrust.Sdk.Anthropic
dotnet add package Anthropic

Wrap the Anthropic client

Call .WithBraintrust() on the Anthropic client. Once wrapped, every Messages.Create call (including streaming) emits a span.

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using Anthropic;
using Anthropic.Models.Messages;
using Braintrust.Sdk.Anthropic;

class AnthropicTracing
{
    static async Task Main(string[] args)
    {
        // Wrap the Anthropic client with Braintrust instrumentation
        var client = new AnthropicClient().WithBraintrust();

        // All API calls are automatically logged
        var result = await client.Messages.Create(new MessageCreateParams
        {
            Model = "claude-sonnet-4-5-20250929",
            MaxTokens = 1024,
            Messages = new List<MessageParam>
            {
                new MessageParam { Role = "user", Content = "What is machine learning?" }
            }
        });

        if (result.Content[0].TryPickText(out var textBlock))
        {
            Console.WriteLine(textBlock.Text);
        }
    }
}

Azure OpenAI

Add the Azure OpenAI integration package

dotnet add package Braintrust.Sdk.AzureOpenAI

Wrap the Azure OpenAI client

Create an instrumented client with WrapAzureOpenAI, then pass your Azure deployment name to GetChatClient.

#skip-compile

using Azure.AI.OpenAI;
using Braintrust.Sdk;
using Braintrust.Sdk.AzureOpenAI;
using OpenAI.Chat;

var braintrust = Braintrust.Sdk.Braintrust.Get();
var activitySource = braintrust.GetActivitySource();

var endpoint = new Uri(Environment.GetEnvironmentVariable("AZURE_OPENAI_ENDPOINT"));
var apiKey = Environment.GetEnvironmentVariable("AZURE_OPENAI_API_KEY");

// Create an instrumented Azure OpenAI client
var client = BraintrustAzureOpenAI.WrapAzureOpenAI(activitySource, endpoint, apiKey);

// Use your Azure deployment name, not the underlying model name
var chatClient = client.GetChatClient("gpt-5-mini");
var response = await chatClient.CompleteChatAsync(
    new ChatMessage[]
    {
        new UserChatMessage("What is the capital of France?")
    });

For Microsoft Entra ID authentication, pass a TokenCredential to WrapAzureOpenAI in place of the API key. See the Azure AI Foundry integration for details.

Microsoft Agent Framework

Add the Agent Framework integration package

dotnet add package Braintrust.Sdk.AgentFramework
dotnet add package Microsoft.Agents.AI.OpenAI

Add Braintrust tracing to your agent

UseBraintrustTracing instruments the LLM and tool calls on the ChatClientBuilder, and WithBraintrustAgentTracing wraps the agent so each run is captured as a span.

#skip-compile

using Braintrust.Sdk;
using Braintrust.Sdk.AgentFramework;
using Microsoft.Agents.AI;
using Microsoft.Extensions.AI;
using OpenAI;

var braintrust = Braintrust.Sdk.Braintrust.Get();
var activitySource = braintrust.GetActivitySource();

// Add Braintrust tracing to the chat client (LLM calls + function calls)
var chatClient = new OpenAIClient(Environment.GetEnvironmentVariable("OPENAI_API_KEY"))
    .GetChatClient("gpt-5-mini").AsIChatClient()
    .AsBuilder()
    .UseBraintrustTracing(activitySource)
    .Build();

var getWeather = AIFunctionFactory.Create(
    (string city) => $"The weather in {city} is sunny, 72°F.",
    "GetWeather",
    "Gets the current weather for a city.");

// Wrap the agent so each run is traced
var agent = new ChatClientAgent(
        chatClient,
        instructions: "You are a helpful assistant. Use tools when appropriate.",
        name: "WeatherAgent",
        tools: [getWeather])
    .WithBraintrustAgentTracing(activitySource);

var session = await agent.CreateSessionAsync();
var response = await agent.RunAsync("What's the weather like in Seattle?", session);
Console.WriteLine(response.Text);

Install and instrument

Install the SDK

Set an API key

Configure tracing

Verify tracing

Next steps

​Sign up

​Install the SDK

​Set an API key

​Configure tracing

​Verify tracing

​Next steps

Sign up

Install the SDK

Set an API key

Configure tracing

Verify tracing

Next steps