@crewai-ts/a2a

Agent-to-Agent (A2A) protocol and A2UI features for CrewAI TypeScript.

This package implements the Google A2A protocol for delegating tasks between agents, plus A2UI (Agent-to-User Interface) schema support for structured agent-to-user interactions.

Install

npm install @crewai-ts/a2a

Requirements:

• Node.js 22 or later
• @crewai-ts/core 0.2.0 or later

Quick Start

Register the A2A hooks so agents can delegate to other agents via the A2A protocol:

import { Agent } from "@crewai-ts/core";
import "@crewai-ts/a2a"; // auto-registers hooks on import

const agent = new Agent({
  role: "Coordinator",
  goal: "Delegate tasks to specialist agents",
  backstory: "An orchestrator that uses A2A delegation.",
  a2a: {
    agents: [
      { name: "researcher", url: "http://localhost:3001/agent.json" },
    ],
  },
});

A2A Protocol

The A2A protocol supports:

• Agent cards — discoverable agent metadata with transport negotiation
• Task delegation — send tasks to remote agents and receive results
• Streaming — receive partial results as they are generated
• Push notifications — register callbacks for async task completion
• Authentication — JWT-based auth between agents

Agent Cards

import { A2AAgentCard } from "@crewai-ts/a2a";

const card: A2AAgentCard = {
  name: "researcher",
  url: "https://agents.example.com/researcher",
  preferredTransport: "HTTP+JSON",
};

A2UI Schemas

Load and validate A2UI schemas for structured agent-to-user interfaces:

import { loadSchema, A2UIModel } from "@crewai-ts/a2a";

const schema = loadSchema("server_to_client", { version: "v0.9" });
const model = A2UIModel.modelValidate(schema);

Exports

• A2AAgentCard, A2AAgentInterface, A2AAgentResponseProtocol
• A2ATransport, A2AProtocolVersion, A2ANegotiationSource
• loadSchema, A2UIModel, A2UIRecord
• Task execution helpers: _execute_task_with_a2a, wrap_agent_with_a2a_instance

License

MIT