Anthropic.SDK

Anthropic.SDK is an unofficial C# client designed for interacting with the Claude AI API. This powerful interface simplifies the integration of the Claude AI into your C# applications. It targets netstandard2.0, and .net6.0.

Table of Contents

• Installation
• API Keys
• IHttpClientFactory
• Usage
• Examples
  • Non-Streaming Call
  • Streaming Call
  • Legacy Endpoints
• Contributing
• License

Installation

Install Anthropic.SDK via the NuGet package manager:

PM> Install-Package Anthropic.SDK

API Keys

You can load the API Key from an environment variable named ANTHROPIC_API_KEY by default. Alternatively, you can supply it as a string to the AnthropicClient constructor.

IHttpClientFactory

The AnthropicClient can optionally take an IHttpClientFactory, which allows you to control elements such as retries and timeouts.

Usage

To start using the Claude AI API, simply create an instance of the AnthropicClient class.

Examples

Non-Streaming Call

Here's an example of a non-streaming call to the Claude AI API to the new Claude 3 Sonnet model:

var client = new AnthropicClient();
var messages = new List<Message>();
messages.Add(new Message()
{
    Role = RoleType.User,
    Content = "Write me a sonnet about the Statue of Liberty"
});
var parameters = new MessageParameters()
{
    Messages = messages,
    MaxTokens = 512,
    Model = AnthropicModels.Claude3Sonnet,
    Stream = false,
    Temperature = 1.0m,
};
var res = await client.Messages.GetClaudeMessageAsync(parameters);

Streaming Call

The following is an example of a streaming call to the Claude AI API Model 3 Opus that provides an image for analysis:

string resourceName = "Anthropic.SDK.Tests.Red_Apple.jpg";

// Get the current assembly
Assembly assembly = Assembly.GetExecutingAssembly();

// Get a stream to the embedded resource
await using Stream stream = assembly.GetManifestResourceStream(resourceName);
// Read the stream into a byte array
byte[] imageBytes;
using (var memoryStream = new MemoryStream())
{
    await stream.CopyToAsync(memoryStream);
    imageBytes = memoryStream.ToArray();
}

// Convert the byte array to a base64 string
string base64String = Convert.ToBase64String(imageBytes);

var client = new AnthropicClient();
var messages = new List<Message>();
messages.Add(new Message()
{
    Role = RoleType.User,
    Content = new dynamic[]
    {
        new ImageContent()
        {
            Source = new ImageSource()
            {
                MediaType = "image/jpeg",
                Data = base64String
            }
        },
        new TextContent()
        {
            Text = "What is this a picture of?"
        }
    }
});
var parameters = new MessageParameters()
{
    Messages = messages,
    MaxTokens = 512,
    Model = AnthropicModels.Claude3Opus,
    Stream = true,
    Temperature = 1.0m,
};
var outputs = new List<MessageResponse>();
await foreach (var res in client.Messages.StreamClaudeMessageAsync(parameters))
{
    if (res.Delta != null)
    {
        Console.Write(res.Delta.Text);
    }

    outputs.Add(res);
}
Console.WriteLine(string.Empty);
Console.WriteLine($@"Used Tokens - Input:{outputs.First().StreamStartMessage.Usage.InputTokens}.
                            Output: {outputs.Last().Usage.OutputTokens}");

Legacy Endpoints

This SDK still supports the Completion endpoints for now, but has primarily moved to the Messages API endpoints. Token calculation does not use the typical cl100k_base that most OpenAI models use, and instead uses it's own byte-pair encoding. A simple extension method has been added to accurately calculate the number of tokens used by both a prompt and a response. See an example below.

var client = new AnthropicClient();
var prompt = AnthropicSignals.HumanSignal + "Write me a sonnet about The Statue of Liberty." + 
         AnthropicSignals.AssistantSignal;

var parameters = new SamplingParameters()
{
    // required    
    Model = AnthropicModels.Claude_v2_1
    Prompt = prompt,
    MaxTokensToSample = 512,

    //optional
    Temperature = 1,
    TopK = 1,
    TopP = 1
    StopSequences = new[] { AnthropicSignals.HumanSignal },
    Stream = false
};

var response = await client.Completions.GetClaudeCompletionAsync(parameters);
Console.WriteLine($@"Tokens Used: Input - {prompt.GetClaudeTokenCount()}. Output - {response.Completion.GetClaudeTokenCount()}.");

Contributing

Pull requests are welcome. If you're planning to make a major change, please open an issue first to discuss your proposed changes.

License

This project is licensed under the MIT License.