A2A-NET

Agent-to-Agent (A2A) is a lightweight, extensible protocol and framework for orchestrating tasks and exchanging structured content between autonomous agents using JSON-RPC 2.0.

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🧩 Projects

🧠 Core

• a2a-net.Core
  Contains the core abstractions, models, contracts, and data types shared across both clients and servers.
  This package is dependency-free and safe to use in any environment.

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📡 Client

• a2a-net.Client.Abstractions
  Contains core interfaces and contracts for implementing A2A clients.

• a2a-net.Client
  Includes client-side functionality for A2A agent discovery and metadata resolution.

• a2a-net.Client.Http
  Implements the HTTP transport for IA2AProtocolClient Allows establishing persistent agent-to-agent communication over HTTP connections.

• a2a-net.Client.WebSocket
  Implements the WebSocket transport for IA2AProtocolClient Allows establishing persistent agent-to-agent communication over WebSocket connections.

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🛠️ Server

• a2a-net.Server
  Core components for building A2A-compatible agents.
  Includes task execution, state management, event streaming, and runtime integration.

• a2a-net.Server.AspNetCore
  ASP.NET Core integration layer that allows hosting A2A endpoints over WebSocket using JSON-RPC.
  Provides middleware, routing, and server bootstrap extensions.

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🧱 Server Infrastructure

• a2a-net.Server.Infrastructure.Abstractions
  Defines abstractions for task persistence, event streaming, and other infrastructure concerns.
  Enables support for custom and pluggable storage/event backends.

• a2a-net.Server.Infrastructure.DistributedCache
  Distributed cache–based implementation of A2A task storage using IDistributedCache.
  Useful for scenarios that require scalable, lightweight task state persistence.

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🚀 Getting Started

Install the packages

dotnet add package a2a-net.Client
dotnet add package a2a-net.Client.Http
dotnet add package a2a-net.Client.WebSocket
dotnet add package a2a-net.Server.Infrastructure.DistributedCache
dotnet add package a2a-net.Server.AspNetCore

Discover a remote agent

 var discoveryDocument = await httpClient.GetA2ADiscoveryDocumentAsync(new Uri("http://localhost"));

Configure and use a client

services.AddA2ProtocolHttpClient(options => 
{
    options.Endpoint = new("http://localhost/a2a");
});

services.AddA2ProtocolWebSocketClient(options => 
{
    options.Endpoint = new("ws://localhost/a2a");
});

var request = new SendTaskRequest()
{
    Params = new()
    {
        Message = new()
        {
            Role = MessageRole.User,
            Parts =
            [
                new TextPart("tell me a joke")
            ]
        }
    }
};
var response = await Client.SendTaskAsync(request);

Host an agent

Configure services

services.AddDistributedMemoryCache();
services.AddA2AProtocolServer(builder =>
{
    builder
        .SupportsStreaming()
        .SupportsPushNotifications()
        .SupportsStateTransitionHistory()
        .UseAgentRuntime<MockAgentRuntime>()
        .UseDistributedCacheTaskRepository();
});

Map A2A Endpoints

app.MapA2AAgentHttpEndpoint("/a2a");
app.MapA2AAgentWebSocketEndpoint("/a2a/ws")

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📚 Documentation

For a full overview of the A2A protocol, see google.github.io/A2A

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🧪 Samples

Explore sample projects demonstrating how to use the a2a-net solution:

• Semantic Kernel: Demonstrates how to build and host an A2A-compatible agent using Microsoft's Semantic Kernel and OpenAI. Includes both a server that exposes the agent and a client that interacts with it over HTTP using the JSON-RPC protocol.

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🛡 License

This project is licensed under the Apache-2.0 License.

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🤝 Contributing

Contributions are welcome! Please open issues and PRs to help improve the ecosystem.

See contribution guidelines for more information on how to contribute.