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Crate lc_a2a

Crate lc_a2a 

Source
Expand description

A2A (Agent-to-Agent) protocol support.

This module implements the A2A protocol for inter-agent communication. It enables LangChain Rust agents to discover, invoke, and communicate with other agents over HTTP using a JSON-RPC style protocol.

§Architecture

  • protocol: Core data types (AgentCard, A2ATask, A2ARequest, etc.)
  • server: A2AServer - handler functions to expose an agent via A2A
  • client: A2AClient - HTTP client to connect to remote A2A agents

§Quick Start

§Server (expose your agent)

ⓘ
use lc_a2a::{A2AServer, AgentCard};
use lc_chains::LLMChain;
use std::sync::Arc;

let chain = Arc::new(LLMChain::new(llm, "You are a helpful assistant"));
let server = A2AServer::new(chain)
    .with_card(AgentCard::new("my-agent", "A helpful agent", "http://localhost:8080"));

// In your HTTP handler (axum, actix, warp, etc.):
// GET /.well-known/agent.json -> server.get_agent_card()
// POST / -> server.handle_a2a_request(body).await

§Client (call a remote agent)

ⓘ
use lc_a2a::{A2AClient, A2AMessage};

let client = A2AClient::new("http://localhost:8080".to_string());
let card = client.get_agent_card().await?;
let task = client.send_task(A2AMessage::user("hello")).await?;

Re-exports§

pub use client::A2AClient;
pub use client::A2AError;
pub use protocol::A2AErrorData;
pub use protocol::A2AMessage;
pub use protocol::A2ARequest;
pub use protocol::A2AResponse;
pub use protocol::A2ATask;
pub use protocol::A2ATaskResult;
pub use protocol::AgentCard;
pub use protocol::TaskStatus;
pub use server::A2AServer;

Modules§

client
A2A Client - connects to remote A2A agents over HTTP.
protocol
A2A (Agent-to-Agent) protocol types.
server
A2A Server - handler functions for the Agent-to-Agent protocol.