The first release of the SDK covers most key features of the protocol: handling agent capability discovery, direct messaging, task-based interactions, and working with streaming data. It supports quick interactions, long workflows, and real-time operations. On the remote agent side, you can use ASP.NET Core to add A2A support to existing agents.
The .NET A2A SDK is being developed in the open on GitHub and is distributed via NuGet. It’s licensed using the Apache 2.0 license, so it should be compatible with most enterprise open source policies. It’s important to remember that this is a preview, and both the SDK and the A2A protocol are likely to change. For one thing, the A2A protocol was only released at the beginning of April 2025.
Building your first A2A interface
Getting started with the preview is easy enough. All you need is a recent .NET release (Version 8.0 or later) and your choice of .NET development environment. You can then create a basic agent, installing the A2A and A2A ASP.NET Core packages from NuGet via the .NET CLI. Sample code should help you get started; there’s support for clients and servers, as well as Semantic Kernel.
