Crate a2a_rs 

A Rust implementation of the Agent-to-Agent (A2A) Protocol

This library provides a type-safe, idiomatic Rust implementation of the A2A protocol, with support for both client and server roles. The implementation follows a hexagonal architecture with clear separation between domains, ports, and adapters.

Features

• Complete implementation of the A2A protocol
• Support for HTTP and WebSocket transport
• Support for streaming updates
• Async and sync interfaces
• Feature flags for optional dependencies

Examples

Creating a client

use a2a_rs::{HttpClient, Message};
use a2a_rs::services::AsyncA2AClient;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Create a client
    let client = HttpClient::new("https://example.com/api".to_string());

    // Send a task message
    let message = Message::user_text("Hello, world!".to_string(), "msg-123".to_string());
    let task = client.send_task_message("task-123", &message, None, None).await?;

    println!("Task: {:?}", task);
    Ok(())
}

Creating a server

use a2a_rs::{HttpServer, SimpleAgentInfo, DefaultRequestProcessor};
use my_app::{MyMessageHandler, MyTaskManager, MyNotificationManager};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Create custom handlers that implement the required traits
    let message_handler = MyMessageHandler::new();
    let task_manager = MyTaskManager::new();
    let notification_manager = MyNotificationManager::new();
    let agent_info = SimpleAgentInfo::new("my-agent".to_string(), "https://api.example.com".to_string());

    // Create a request processor with your handlers
    let processor = DefaultRequestProcessor::new(
        message_handler,
        task_manager,
        notification_manager,
        agent_info.clone(),
    );

    // Create and start the server
    let server = HttpServer::new(
        processor,
        agent_info,
        "127.0.0.1:8080".to_string(),
    );
    server.start().await?;
    Ok(())
}

Re-exports

pub use domain::A2AError;

pub use domain::AgentCapabilities;

pub use domain::AgentCard;

pub use domain::AgentCardSignature;

pub use domain::AgentExtension;

pub use domain::AgentInterface;

pub use domain::AgentProvider;

pub use domain::AgentSkill;

pub use domain::Artifact;

pub use domain::AuthorizationCodeOAuthFlow;

pub use domain::ClientCredentialsOAuthFlow;

pub use domain::DeleteTaskPushNotificationConfigParams;

pub use domain::FileContent;

pub use domain::GetTaskPushNotificationConfigParams;

pub use domain::ImplicitOAuthFlow;

pub use domain::ListTaskPushNotificationConfigParams;

pub use domain::ListTasksParams;

pub use domain::ListTasksResult;

pub use domain::Message;

pub use domain::MessageSendConfiguration;

pub use domain::MessageSendParams;

pub use domain::OAuthFlows;

pub use domain::Part;

pub use domain::PasswordOAuthFlow;

pub use domain::PushNotificationAuthenticationInfo;

pub use domain::PushNotificationConfig;

pub use domain::Role;

pub use domain::SecurityScheme;

pub use domain::Task;

pub use domain::TaskArtifactUpdateEvent;

pub use domain::TaskIdParams;

pub use domain::TaskPushNotificationConfig;

pub use domain::TaskQueryParams;

pub use domain::TaskSendParams;

pub use domain::TaskState;

pub use domain::TaskStatus;

pub use domain::TaskStatusUpdateEvent;

pub use domain::TransportProtocol;

pub use port::AsyncMessageHandler;

pub use port::AsyncNotificationManager;

pub use port::AsyncStreamingHandler;

pub use port::AsyncTaskManager;

pub use port::MessageHandler;

pub use port::NotificationManager;

pub use port::StreamingHandler;

pub use port::StreamingSubscriber;

pub use port::TaskManager;

pub use port::UpdateEvent;

pub use adapter::DefaultRequestProcessor;

pub use adapter::InMemoryTaskStorage;

pub use adapter::NoopPushNotificationSender;

pub use adapter::PushNotificationRegistry;

pub use adapter::PushNotificationSender;

pub use adapter::SimpleAgentInfo;

Modules

adapter

Adapters for the A2A protocol

application

Application services for the A2A protocol

domain

Domain models for the A2A protocol

observability

Observability and logging utilities for a2a-rs

port

Ports (interfaces) for the A2A protocol

services

Service layer for the A2A protocol

Macros

log_error

Helper macros for consistent error logging

measure_duration

Helper macro for performance tracking