Building Smart Agent-to-Agent (A2A) Applications with Kotlin

In this comprehensive guide, we'll explore how to create intelligent agents using the A2A (Agent-to-Agent) protocol in Kotlin. We'll build a practical example that demonstrates how agents can communicate and work together to solve complex tasks. As part of this tutorial we will build agent from the sample provided here

What is the A2A Protocol?

The Agent-to-Agent (A2A) protocol is a modern approach to building distributed AI-powered applications. It provides a standardized way for software agents to communicate and delegate tasks, making it easier to create scalable and modular AI systems.

Key features of the A2A protocol include:

• Standardized communication between agents
• Dynamic task delegation based on agent capabilities
• Support for both synchronous and asynchronous operations
• Extensible architecture for adding new agents and capabilities

Setting Up Your A2A Project

Let's start by creating a new Kotlin project with the necessary dependencies. We'll use Spring Boot and the a2ajava library.

plugins {
    kotlin("jvm") version "2.1.0"
    kotlin("plugin.spring") version "2.1.0"
    id("org.springframework.boot") version "3.2.5"
}

dependencies {
    implementation("io.github.vishalmysore:a2ajava:0.0.7.9")
    implementation("org.springframework.boot:spring-boot-starter-web")
}

Creating Your First Agent

Let's create a simple WeatherAgent that provides weather information:

@Agent(groupName = "Weather Service", groupDescription = "Provides current weather info")
open class WeatherAgent {
    @Action(description = "Get temperature for a given city")
    fun getTemperature(city: String): String {
        return "The current temperature in $city is 25°C"
    }
}

The @Agent annotation defines our agent's identity and capabilities, while @Action marks methods that other agents can invoke.

Setting Up the Server

To make our agents accessible, we need to set up a server. Here's our main application class:

@SpringBootApplication
class A2AKotlinApp

fun main(args: Array<String>) {
    runApplication<A2AKotlinApp>(*args)
    var client = LocalA2ATaskClient()
    var response = client.sendTask("hows the weather in London")
    println("Response: $response")
}

Real-Time Agent Communication

One of the powerful features of A2A is real-time communication between agents. Here's how agents interact:

When agents communicate, they can:

1. Exchange structured messages
2. Delegate tasks
3. Share results and status updates

Advanced Agent Interactions

Agents can have complex conversations and handle multiple tasks:

Monitoring Agent Events

The A2A protocol provides built-in support for monitoring agent activities:

This helps in:

• Tracking task execution
• Monitoring agent performance
• Debugging agent interactions

Adding More Complex Agents

Let's look at a more sophisticated agent that handles route planning:

@Agent(
    groupName = "GeoSpatial Route Planner Agent",
    groupDescription = "Provides advanced route planning services"
)
class RoutePlanner {
    @Action(description = "Calculates optimal route between two locations")
    fun planOptimalRoute(origin: String, destination: String): String {
        return "Optimal route from $origin to $destination calculated."
    }
}

Best Practices for A2A Development

1. Agent Design

   • Keep agents focused on specific domains
   • Use clear and descriptive action names
   • Implement proper error handling

2. Communication

   • Use structured data formats
   • Implement timeouts for synchronous operations
   • Handle communication failures gracefully

3. Testing

   • Test agents in isolation
   • Verify agent interactions
   • Monitor performance metrics

Deploying A2A Applications

To deploy your A2A application:

1. Build the application:

   ./gradlew build

1. Run the server:

   ./gradlew bootRun

Your agents will be available at:

• Server: http://localhost:8080
• Agent Card: http://localhost:8080/.well-known/agent.json

Conclusion

The A2A protocol provides a powerful framework for building intelligent, distributed applications. By following this guide, you've learned how to:

• Create intelligent agents in Kotlin
• Set up agent communication
• Monitor agent activities
• Deploy A2A applications

The combination of Kotlin's expressiveness and A2A's powerful features makes it easy to build sophisticated agent-based systems that can solve complex real-world problems.

Resources

• Project Source Code