Anthropic.SDK 4.0.0

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 NetStandard 2.0, .NET 6.0, and .NET 8.0.

Table of Contents

• Installation
• API Keys
• HttpClient
• Usage
• Examples
  • Non-Streaming Call
  • Streaming Call
  • Tools
• 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.

HttpClient

The AnthropicClient can optionally take a custom HttpClient in the AnthropicClient constructor, which allows you to control elements such as retries and timeouts. Note: If you provide your own HttpClient, you are responsible for disposal of that client.

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>()
{
    new Message(RoleType.User, "Who won the world series in 2020?"),
    new Message(RoleType.Assistant, "The Los Angeles Dodgers won the World Series in 2020."),
    new Message(RoleType.User, "Where was it played?"),
};

var parameters = new MessageParameters()
{
    Messages = messages,
    MaxTokens = 1024,
    Model = AnthropicModels.Claude35Sonnet,
    Stream = false,
    Temperature = 1.0m,
};
var firstResult = await client.Messages.GetClaudeMessageAsync(parameters);

//print result
Console.WriteLine(firstResult.Message.ToString());

//print remaining Request Limit
Console.WriteLine(firstResult.RateLimits.RequestsLimit.ToString());

//add assistant message to chain for second call
messages.Add(firstResult.Message);

//ask followup question in chain
messages.Add(new Message(RoleType.User,"Who were the starting pitchers for the Dodgers?"));

var finalResult = await client.Messages.GetClaudeMessageAsync(parameters);

//print result
Console.WriteLine(finalResult.Message.ToString());

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 List<ContentBase>()
    {
        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}");

Tools

The AnthropicClient supports function-calling through a variety of methods, see some examples below or check out the unit tests in this repo (note function-calling is currently only supported in non-streaming calls by Claude at the moment):

//From a globally declared static function:
public enum TempType
{
    Fahrenheit,
    Celsius
}

[Function("This function returns the weather for a given location")]
public static async Task<string> GetWeather([FunctionParameter("Location of the weather", true)]string location,
    [FunctionParameter("Unit of temperature, celsius or fahrenheit", true)] TempType tempType)
{
    return "72 degrees and sunny";
}

var client = new AnthropicClient();
var messages = new List<Message>
{
    new Message(RoleType.User, "What is the weather in San Francisco, CA in fahrenheit?")
};


var tools = Common.Tool.GetAllAvailableTools(includeDefaults: false, 
    forceUpdate: true, clearCache: true);

var parameters = new MessageParameters()
{
    Messages = messages,
    MaxTokens = 2048,
    Model = AnthropicModels.Claude3Sonnet,
    Stream = false,
    Temperature = 1.0m,
    Tools = tools.ToList()
};
var res = await client.Messages.GetClaudeMessageAsync(parameters);

messages.Add(res.Message);

foreach (var toolCall in res.ToolCalls)
{
    var response = await toolCall.InvokeAsync<string>();
    
    messages.Add(new Message(toolCall, response));
}

var finalResult = await client.Messages.GetClaudeMessageAsync(parameters);

//The weather in San Francisco, CA is currently 72 degrees Fahrenheit and sunny.

//Streaming example
var client = new AnthropicClient();
var messages = new List<Message>();
messages.Add(new Message(RoleType.User, "What's the temperature in San diego right now in Fahrenheit?"));
var tools = Common.Tool.GetAllAvailableTools(includeDefaults: false, forceUpdate: true, clearCache: true);
var parameters = new MessageParameters()
{
    Messages = messages,
    MaxTokens = 512,
    Model = AnthropicModels.Claude35Sonnet,
    Stream = true,
    Temperature = 1.0m,
    Tools = tools.ToList()
};
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);
}

messages.Add(new Message(outputs));

foreach (var output in outputs)
{
    if (output.ToolCalls != null)
    {
        
        foreach (var toolCall in output.ToolCalls)
        {
            var response = await toolCall.InvokeAsync<string>();

            messages.Add(new Message(toolCall, response));
        }
    }
}

await foreach (var res in client.Messages.StreamClaudeMessageAsync(parameters))
{
    if (res.Delta != null)
    {
        Console.Write(res.Delta.Text);
    }

    outputs.Add(res);
}
//The weather in San Diego, CA is currently 72 degrees Fahrenheit and sunny.


//From a Func:

var client = new AnthropicClient();
var messages = new List<Message>
{
    new Message(RoleType.User, "What is the weather in San Francisco, CA?")
};
var tools = new List<Common.Tool>
{
    Common.Tool.FromFunc("Get_Weather", 
        ([FunctionParameter("Location of the weather", true)]string location)=> "72 degrees and sunny")
};

var parameters = new MessageParameters()
{
    Messages = messages,
    MaxTokens = 2048,
    Model = AnthropicModels.Claude3Sonnet,
    Stream = false,
    Temperature = 1.0m,
    Tools = tools
};
var res = await client.Messages.GetClaudeMessageAsync(parameters);

messages.Add(res.Message);

foreach (var toolCall in res.ToolCalls)
{
    var response = toolCall.Invoke<string>();

    messages.Add(new Message(toolCall, response));
}

var finalResult = await client.Messages.GetClaudeMessageAsync(parameters);


//From a static Object

public static class StaticObjectTool
{
    
    public static string GetWeather(string location)
    {
        return "72 degrees and sunny";
    }
}

var client = new AnthropicClient();
var messages = new List<Message>
{
    new Message(RoleType.User, "What is the weather in San Francisco, CA?")
};

var tools = new List<Common.Tool>
{
    Common.Tool.GetOrCreateTool(typeof(StaticObjectTool), nameof(GetWeather), "This function returns the weather for a given location")
};

var parameters = new MessageParameters()
{
    Messages = messages,
    MaxTokens = 2048,
    Model = AnthropicModels.Claude3Sonnet,
    Stream = false,
    Temperature = 1.0m,
    Tools = tools
};
var res = await client.Messages.GetClaudeMessageAsync(parameters);

messages.Add(res.Message);

foreach (var toolCall in res.ToolCalls)
{
    var response = toolCall.Invoke<string>();

    messages.Add(new Message(toolCall, response));
}

var finalResult = await client.Messages.GetClaudeMessageAsync(parameters);

//From an object instance

public class InstanceObjectTool
{

    public string GetWeather(string location)
    {
        return "72 degrees and sunny";
    }
}
var client = new AnthropicClient();
var messages = new List<Message>
{
    new Message(RoleType.User, "What is the weather in San Francisco, CA?")
};

var objectInstance = new InstanceObjectTool();
var tools = new List<Common.Tool>
{
    Common.Tool.GetOrCreateTool(objectInstance, nameof(GetWeather), "This function returns the weather for a given location")
};
....

//Manual

var client = new AnthropicClient();
var messages = new List<Message>
{
    new Message(RoleType.User, "What is the weather in San Francisco, CA in fahrenheit?")
};
var inputschema = new InputSchema()
{
    Type = "object",
    Properties = new Dictionary<string, Property>()
    {
        { "location", new Property() { Type = "string", Description = "The location of the weather" } },
        {
            "tempType", new Property()
            {
                Type = "string", Enum = Enum.GetNames(typeof(TempType)),
                Description = "The unit of temperature, celsius or fahrenheit"
            }
        }
    },
    Required = new List<string>() { "location", "tempType" }
};
JsonSerializerOptions jsonSerializationOptions  = new()
{
    DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
    Converters = { new JsonStringEnumConverter() },
    ReferenceHandler = ReferenceHandler.IgnoreCycles,
};
string jsonString = JsonSerializer.Serialize(inputschema, jsonSerializationOptions);
var tools = new List<Common.Tool>()
{
    new Function("GetWeather", "This function returns the weather for a given location",
        JsonNode.Parse(jsonString))
};
var parameters = new MessageParameters()
{
    Messages = messages,
    MaxTokens = 2048,
    Model = AnthropicModels.Claude3Sonnet,
    Stream = false,
    Temperature = 1.0m,
    Tools = tools
};
var res = await client.Messages.GetClaudeMessageAsync(parameters);

messages.Add(res.Message);

var toolUse = res.Content.OfType<ToolUseContent>().First();
var id = toolUse.Id;
var param1 = toolUse.Input["location"].ToString();
var param2 = Enum.Parse<TempType>(toolUse.Input["tempType"].ToString());

var weather = await GetWeather(param1, param2);

messages.Add(new Message()
{
    Role = RoleType.User,
    Content = new List<ContentBase>() { new ToolResultContent()
    {
        ToolUseId = id,
        Content = weather
    }
}});

var finalResult = await client.Messages.GetClaudeMessageAsync(parameters);

//Json Mode - Advanced Usage

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

Assembly assembly = Assembly.GetExecutingAssembly();

await using Stream stream = assembly.GetManifestResourceStream(resourceName);
byte[] imageBytes;
using (var memoryStream = new MemoryStream())
{
    await stream.CopyToAsync(memoryStream);
    imageBytes = memoryStream.ToArray();
}

string base64String = Convert.ToBase64String(imageBytes);

var client = new AnthropicClient();

var messages = new List<Message>();

messages.Add(new Message()
{
    Role = RoleType.User,
    Content = new List<ContentBase>()
    {
        new ImageContent()
        {
            Source = new ImageSource()
            {
                MediaType = "image/jpeg",
                Data = base64String
            }
        },
        new TextContent()
        {
            Text = "Use `record_summary` to describe this image."
        }
    }
});

var imageSchema = new ImageSchema
{
    Type = "object",
    Required = new string[] { "key_colors", "description"},
    Properties = new Properties()
    {
        KeyColors = new KeyColorsProperty
        {
        Items = new ItemProperty
        {
            Properties = new Dictionary<string, ColorProperty>
            {
                { "r", new ColorProperty { Type = "number", Description = "red value [0.0, 1.0]" } },
                { "g", new ColorProperty { Type = "number", Description = "green value [0.0, 1.0]" } },
                { "b", new ColorProperty { Type = "number", Description = "blue value [0.0, 1.0]" } },
                { "name", new ColorProperty { Type = "string", Description = "Human-readable color name in snake_case, e.g. 'olive_green' or 'turquoise'" } }
            }
        }
    },
        Description = new DescriptionDetail { Type = "string", Description = "Image description. One to two sentences max." },
        EstimatedYear = new EstimatedYear { Type = "number", Description = "Estimated year that the images was taken, if is it a photo. Only set this if the image appears to be non-fictional. Rough estimates are okay!" }
    }
    
};

JsonSerializerOptions jsonSerializationOptions = new()
{
    DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
    Converters = { new JsonStringEnumConverter() },
    ReferenceHandler = ReferenceHandler.IgnoreCycles,
};
string jsonString = JsonSerializer.Serialize(imageSchema, jsonSerializationOptions);
var tools = new List<Common.Tool>()
{
    new Function("record_summary", "Record summary of an image into well-structured JSON.",
        JsonNode.Parse(jsonString))
};



//with ToolChoice selection
var parameters = new MessageParameters()
{
    Messages = messages,
    MaxTokens = 1024,
    Model = AnthropicModels.Claude3Sonnet,
    Stream = false,
    Temperature = 1.0m,
    Tools = tools,
    ToolChoice = new ToolChoice()
    {
        Type = ToolChoiceType.Tool,
        Name = "record_summary"
    }
};
var res = await client.Messages.GetClaudeMessageAsync(parameters);

var toolResult = res.Content.OfType<ToolUseContent>().First();

var json = toolResult.Input.ToJsonString();

Output From Json Mode

{
  "description": "This image shows a close-up view of a ripe, red apple with shades of yellow and orange. The apple has a shiny, waxy surface with water droplets visible, giving it a fresh appearance.",
  "estimated_year": 2020,
  "key_colors": [
    {
      "r": 1,
      "g": 0.2,
      "b": 0.2,
      "name": "red"
    },
    {
      "r": 1,
      "g": 0.6,
      "b": 0.2,
      "name": "orange"
    },
    {
      "r": 0.8,
      "g": 0.8,
      "b": 0.2,
      "name": "yellow"
    }
  ]
}

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.