This sample demonstrates how to expose a Google ADK (Agent Development Kit) agent via the A2A (Agent-to-Agent) protocol using A2A SDK and Quarkus service.

The application implements a simple conversational agent that checks whether given numbers are prime numbers. It uses the LlmAgent from the Google ADK and exposes it via an A2A server.

• Agent.java: Defines the LlmAgent instance (check_prime_agent) and the checkPrime tool function it uses to verify numbers.
• AgentCardProducer.java: Loads and provides the AgentCard metadata (from agent.json) which defines the agent's identity and capabilities in the A2A network.
• AgentExecutorProducer.java: Configures and provides the A2A AgentExecutor, implemented by the ADK library to wire ADK-owned agents automatically.
• StartupConfig.java: Contains initialization logic, such as registering JSON modules for the Vert.x/Quarkus runtime.
• application.properties: Contains a configuration for the Quarkus service and A2A, such as port where application will be exposed, application name and event processing timeouts.

You can build the project using Maven:

mvn clean install

The Java server can be started using mvn as follow (don't forget to set your GOOGLE_API_KEY before running the service):

export GOOGLE_API_KEY=<YOUR_API_KEY>

cd examples/a2a_server
mvn quarkus:dev

curl -X POST http://localhost:9090 \
  -H 'Content-Type: application/json' \
  -d '{
        "jsonrpc": "2.0",
        "id": "cli-check-2",
        "method": "message/stream",
        "params": {
          "message": {
            "kind": "message",
            "contextId": "cli-demo-context",
            "messageId": "cli-check-2",
            "role": "user",
            "parts": [
              {
                "kind": "text",
                "text": "Is 2 prime?"
              }
            ]
          }
        }
      }'