Anthropic.Client

A strongly-typed, feature-rich .NET client library for Anthropic's Claude API, providing easy integration with Claude's powerful language models.

✨ Features

• 🎯 Strongly-typed models with comprehensive IntelliSense support
• 🔄 Async/await pattern with full cancellation token support
• 🛠️ Fluent builder pattern for easy request construction
• 🔁 Automatic retry logic with exponential backoff and jitter
• 📊 Streaming responses for real-time chat experiences
• 🧰 Tool support for function calling capabilities
• 💾 Prompt caching for improved performance
• 📦 Message batching for high-volume processing
• 🔍 Comprehensive logging with Microsoft.Extensions.Logging
• 🏗️ Extension methods for simplified usage
• ⚡ High performance with System.Text.Json serialization
• 🔧 Configurable options with validation
• 🌐 Multi-framework support (.NET Standard 2.1, .NET 7, .NET 8, .NET 9)

📦 Installation

Install the package via NuGet Package Manager: dotnet add package Anthropic.Client

Or via Package Manager Console: Install-Package Anthropic.Client

🚀 Quick Start

Basic Setup

using Anthropic.Client; 
using Anthropic.Client.Models;
// Configure the client
var options = new AnthropicClientOptions
{
	ApiKey = "your-api-key-here", 	// or set ANTHROPIC_API_KEY environment variable
	EnableLogging = true,
	MaxRetries = 3,
	Timeout = TimeSpan.FromSeconds(100)
};

// Create the client
using var client = new AnthropicClient(options);

Simple Message Request

var request = new MessagesRequest
{
	Model = AnthropicModels.Claude35Sonnet,
	MaxTokens = 1000,
	Messages = new List<Message>
	{
		new Message
		{
			Role = "user",
			Content = "Hello, Claude!"
		}
	}
};

var response = await client.CreateMessagesAsync(request);
Console.WriteLine(response.Content[0].Text);

📚 Available Models

The library includes constants for all available Claude models:

// Claude 3.5 models (recommended)
AnthropicModels.Claude35Sonnet  // "claude-3-5-sonnet-20241022"
AnthropicModels.Claude35Haiku   // "claude-3-5-haiku-20241022"
// Claude 3 models
AnthropicModels.Claude3Opus	// "claude-3-opus-20240229"
AnthropicModels.Claude3Sonnet   // "claude-3-sonnet-20240229"
AnthropicModels.Claude3Haiku    // "claude-3-haiku-20240307"

🏗️ Builder Pattern

Use the fluent builder pattern for clean, readable request construction:

using Anthropic.Client.Builders;
var request = MessagesRequestBuilder.Create()
	.WithModel(AnthropicModels.Claude35Sonnet)
	.WithMaxTokens(1000)
	.WithTemperature(0.7)
	.WithSystem("You are a helpful assistant.") 
	.AddUserMessage("Explain quantum computing") 
	.AddAssistantMessage("Quantum computing is...") 
	.AddUserMessage("Can you elaborate on quantum entanglement?") 
	.Build();

var response = await client.CreateMessagesAsync(request);

🔧 Extension Methods

Simplified usage with extension methods:

using Anthropic.Client.Extensions;

// Quick single message 
var response = await client.SendMessageAsync(
	"What is the capital of France?",
	AnthropicModels.Claude35Sonnet
);

// With system prompt 
var response = await client.SendMessageAsync(
	"Write a haiku about programming",
	AnthropicModels.Claude35Sonnet,
	systemPrompt: "You are a creative poet"
);

🔄 Streaming Responses

For real-time chat experiences:

var request = new MessagesRequest 
{ 
	Model = AnthropicModels.Claude35Sonnet, 
	MaxTokens = 1000, 
	Messages = new List<Message> 
	{ 
		new Message 
		{ 
			Role = "user", 
			Content = "Tell me a story" 
		}
	}
};

await foreach (var chunk in client.CreateStreamingMessagesAsync(request)) 
{ 
	if (chunk.Type == "content_block_delta") 
	{ 
		Console.Write(chunk.Delta?.Text); 
	} 
}

🧰 Tool Support

Enable function calling capabilities:

var tools = new List<Tool> 
{ 
	new Tool 
	{ 
		Name = "get_weather", 
		Description = "Get current weather for a location", 
		InputSchema = new ToolInputSchema 
		{ 
			Type = "object", 
			Properties = new Dictionary<string, object> 
			{ 
				["location"] = new { type = "string", description = "City name" } 
			}, 
			Required = new[] {"location"} 
		} 
	} 
};
var request = new MessagesRequest 
{ 
	Model = AnthropicModels.Claude35Sonnet, 
	MaxTokens = 1000, 
	Messages = new List<Message> 
	{ 
		new Message 
		{ 
			Role = "user", 
			Content = "What's the weather in New York?" 
		} 
	} 
};

var response = await client.CreateMessagesWithToolsAsync(request, tools);

💾 Prompt Caching

Improve performance with prompt caching:

var request = new MessagesRequest 
{ 
	Model = AnthropicModels.Claude35Sonnet, 
	MaxTokens = 1000, 
	Messages = new List<Message> 
	{ 
		new Message 
		{ 
			Role = "user", 
			Content = "Large context that should be cached...", 
			CacheControl = new CacheControl 
			{ 
				Type = "ephemeral" 
			} 
		} 
	} 
};

var response = await client.CreateMessagesWithCachingAsync(request);

📦 Message Batching

Process multiple requests efficiently:

var requests = new List<MessagesRequest> 
{ 
	new MessagesRequest 
	{ 
		Model = AnthropicModels.Claude35Sonnet, 
		MaxTokens = 100, 
		Messages = new List<Message> 
		{ 
			new Message 
			{ 
				Role = "user", 
				Content = "Translate 'Hello' to French" 
			} 
		} 
	}, 
	new MessagesRequest 
	{ 
		Model = AnthropicModels.Claude35Sonnet, 
		MaxTokens = 100, 
		Messages = new List<Message> 
		{ 
			new Message 
			{ 
				Role = "user", 
				Content = "Translate 'Hello' to Spanish" 
			} 
		} 
	} 
};

var batch = await client.CreateMessageBatchAsync(requests); 
Console.WriteLine($"Batch ID: {batch.Id}");

// Check batch status 
var status = await client.GetMessageBatchAsync(batch.Id); 
Console.WriteLine($"Status: {status.ProcessingStatus}");

⚙️ Configuration Options

var options = new AnthropicClientOptions 
{ 
	ApiKey = "your-api-key",                    // Required 
	BaseUrl = "https://api.anthropic.com",      // Default API endpoint 
	Timeout = TimeSpan.FromSeconds(100),        // Request timeout 
	MaxRetries = 3,                             // Retry attempts 
	EnableLogging = true,                       // Enable request/response logging 
	EnableTelemetry = true,                     // Enable telemetry collection 
	UserAgent = "MyApp/1.0"                     // Custom user agent 
};

// Validate configuration 
options.Validate();

📊 Logging Integration

The client integrates with Microsoft.Extensions.Logging:

using Microsoft.Extensions.Logging;

// Setup logging 
using var loggerFactory = LoggerFactory.Create(builder => builder.AddConsole().SetMinimumLevel(LogLevel.Information));
var logger = loggerFactory.CreateLogger<AnthropicClient>();

// Pass logger to client 
using var client = new AnthropicClient(options, logger: logger);

🔐 Authentication

Set your API key using one of these methods:

1. Environment Variable (Recommended): export ANTHROPIC_API_KEY="your-api-key-here"

2. Configuration Options: var options = new AnthropicClientOptions { ApiKey = "your-api-key-here" };

3. appsettings.json (for ASP.NET Core):

{ 
	"Anthropic": 
	{ 
		"ApiKey": "your-api-key-here" 
	} 
}

🔄 Dependency Injection

Register the client in your DI container:

// Program.cs (ASP.NET Core) 
builder.Services.Configure<AnthropicClientOptions>(builder.Configuration.GetSection("Anthropic"));

builder.Services.AddHttpClient<AnthropicClient>(); 
builder.Services.AddScoped<AnthropicClient>();

🛡️ Error Handling

The client provides comprehensive error handling:

try 
{ 
	var response = await client.CreateMessagesAsync(request); 
} 
catch (AnthropicApiException ex) 
{ 
	Console.WriteLine($"API Error: {ex.Message}"); 
	Console.WriteLine($"Status Code: {ex.StatusCode}"); 
	Console.WriteLine($"Error Type: {ex.ErrorType}"); 
} 
catch (HttpRequestException ex) 
{ 
	Console.WriteLine($"Network Error: {ex.Message}"); 
}

📈 Performance Tips

1. Reuse the client instance - it's thread-safe and designed for reuse
2. Use streaming for long responses to improve perceived performance
3. Enable prompt caching for repeated large contexts
4. Use message batching for high-volume scenarios
5. Configure appropriate timeouts based on your use case

🧪 Testing

The library includes comprehensive test coverage and supports mocking:

// Example test setup 
var mockHttpClient = new Mock<HttpClient>(); 
var client = new AnthropicClient(options, mockHttpClient.Object);

🔧 Advanced Usage

Custom HTTP Client

var httpClient = new HttpClient(); 
httpClient.DefaultRequestHeaders.Add("Custom-Header", "Value");
using var client = new AnthropicClient(options, httpClient);

Retry Configuration

var options = new AnthropicClientOptions 
{ 
	ApiKey = "your-api-key", 
	MaxRetries = 5,  // Custom retry count 
	Timeout = TimeSpan.FromMinutes(2)  // Extended timeout 
};

📋 Requirements

• .NET Standard 2.1 or later
• .NET 7 or later
• .NET 8 or later
• .NET 9 or later

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🔗 Links

• NuGet Package
• GitHub Repository
• Anthropic API Documentation

📞 Support

For issues and questions:

• Create an issue on GitHub
• Check the Anthropic API documentation

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Made with ❤️ by Anubhav Ranjan