Anthropic SDK for C#

Why it's ranked here

This is a strong default for Claude work inside .NET. Anthropic maintains it, distributes it through NuGet, targets .NET Standard 2.0 and later, and backs the core package with tests. Provider-specific projects also reduce friction for teams deploying through major cloud platforms.

What's good

The setup is compact, while typed message parameters keep model, role, content, and token limits explicit. The solution includes dedicated packages for Bedrock, Foundry, Vertex AI, AWS, Google Cloud, and MCP. Automated formatting, analyzer checks, mock-backed tests, and an MIT license strengthen adoption.

Tradeoffs

Most SDK code is generated, so manual patches can conflict with later generator output. The main documentation lives outside the repository. Package history also creates a migration trap: older community-built releases moved to a differently named package, so existing consumers must verify which client they use.

How to use it well

Use it when a C# service or application needs typed, asynchronous Claude requests, especially when cloud-provider packages match your deployment. Install the NuGet package, start from the small message example, and test changes against the supplied mock workflow. Choose another surface if you need a standalone command-line client rather than an embedded library.

Observed

License

MIT License

Primary language

C#

Distribution

NuGet package named Anthropic

Install surface

Library package installed with the .NET package manager

Platform support

.NET Standard 2.0 and later

Interface

Typed C# library for the Claude API

Provider packages

Bedrock, Foundry, Vertex AI, AWS, and Google Cloud projects

Repository structure

Dedicated core test project and a streaming aggregation example project