A2A Ruby SDK

gem 'a2a-ruby'

require 'a2a'

# Create a client
client = A2A::Client::HttpClient.new("https://agent.example.com/a2a")

# Send a message
message = A2A::Types::Message.new(
  message_id: SecureRandom.uuid,
  role: "user",
  parts: [
    A2A::Types::TextPart.new(text: "Hello, agent!")
  ]
)

# Get response (streaming or blocking)
client.send_message(message) do |response|
  case response
  when A2A::Types::Message
    puts "Agent replied: #{response.parts.first.text}"
  when A2A::Types::Task
    puts "Task created: #{response.id}"
  end
end

class MyAgentController < ApplicationController
  include A2A::Server::Agent
  
  # Define agent skills
  a2a_skill "greeting" do |skill|
    skill.description = "Greet users in different languages"
    skill.tags = ["greeting", "conversation", "multilingual"]
    skill.examples = ["Hello", "Say hi in Spanish"]
  end
  
  # Define A2A methods
  a2a_method "greet" do |params|
    language = params[:language] || "en"
    name = params[:name] || "there"
    
    greeting = case language
    when "es" then "¡Hola"
    when "fr" then "Bonjour"
    else "Hello"
    end
    
    {
      message: "#{greeting}, #{name}!",
      language: language
    }
  end
  
  # Handle streaming responses
  a2a_method "chat", streaming: true do |params|
    Enumerator.new do |yielder|
      # Yield task status updates
      yielder << A2A::Types::TaskStatusUpdateEvent.new(
        task_id: params[:task_id],
        context_id: params[:context_id],
        status: A2A::Types::TaskStatus.new(state: "working")
      )
      
      # Process and yield response
      response = process_chat(params[:message])
      yielder << A2A::Types::Message.new(
        message_id: SecureRandom.uuid,
        role: "agent",
        parts: [A2A::Types::TextPart.new(text: response)]
      )
    end
  end
end

# config/routes.rb
Rails.application.routes.draw do
  mount A2A::Engine => "/a2a"
end

# The engine automatically provides:
# POST /a2a/rpc          - JSON-RPC endpoint
# GET  /a2a/agent-card   - Agent card discovery
# GET  /a2a/capabilities - Capabilities endpoint

A2A.configure do |config|
  config.protocol_version = "0.3.0"
  config.default_transport = "JSONRPC"
  config.streaming_enabled = true
  config.push_notifications_enabled = true
  config.default_timeout = 30
  config.log_level = :info
end