Question about A2A protocol architecture and project structure #3124

jigarvyasidea · 2025-09-11T12:30:19Z

jigarvyasidea
Sep 11, 2025

I know this may not be a direct issue, but I wanted to connect with you for clarification. While learning the A2A protocol, I found that information is spread across different places and sometimes a bit unclear.

To better understand, I created a basic A2A project and hosted it in a Jupyter notebook. I’d like to share access to that code with you and request your feedback — specifically, whether the architecture I’ve followed aligns with the right structure for A2A or if I should improve/change something.

Here is notebook URL :- https://colab.research.google.com/drive/1rUTmbMK9d7IpTTbd_ZKx3I9PnkpXdJWl?usp=sharing

I’m actively learning and experimenting with this, so your guidance would be really helpful in the learning process.

Thanks in advance for your time and support

adk-bot · 2025-10-09T00:26:09Z

adk-bot
Oct 9, 2025
Maintainer

Response from ADK Answering Agent (experimental, answer may be inaccurate)

TLDR: Your diagram captures the essence of app-to-app communication, but the ADK provides a higher-level abstraction that handles the underlying connection and authentication details for you. Instead of manually managing tokens and partnerships, the recommended approach is to "expose" one agent as a server and have the other agent "consume" it using the RemoteA2aAgent class, making the remote agent's tools feel like local functions.

Hello @jigarvyasidea,

Thank you for reaching out and for your proactive work in understanding the A2A protocol. The architecture you've designed is a great conceptual model for how two applications can establish a trusted connection!

The ADK aims to simplify this process by abstracting away the low-level networking and authentication steps. Here’s a breakdown of the standard ADK approach to A2A and how it relates to your project:

The ADK A2A Model: Exposing and Consuming

Instead of manually creating partnership objects and exchanging authentication tokens, the ADK framework manages this for you. The primary concepts are:

Exposing an Agent: One of your services (the "provider" or your "App 2") exposes its functionality over the network. The ADK provides two main ways to do this:
- Using the adk api_server --a2a CLI command. This requires an agent.json (also called an agent card) that describes your agent's capabilities.
- Using the to_a2a() utility function within your Python code to convert your agent into a web-servable application. [3]
Consuming an Agent: Your other service (the "consumer" or your "App 1") integrates the remote agent. You do this by configuring a RemoteA2aAgent in your agent's YAML configuration, pointing it to the exposed agent's URL and its agent card. [2]

Once configured, the consuming agent can use the exposed agent's tools as if they were local Python functions. The ADK handles the API calls, data serialization, and connection management in the background. [1]

Recommended Project Structure

Based on the ADK framework, a typical A2A project structure would involve two separate agent implementations:

The Remote (Exposed) Agent: This would be a self-contained ADK agent with its own tools, callbacks, and an agent.json card that defines its public interface.
The Local (Consuming) Agent: This agent would include a RemoteA2aAgent configuration in its *.agent.yaml file to connect to the exposed agent.

For a practical example, I highly recommend looking at the Basic A2A Sample Project. It provides a clear, working example of this structure. [4]

While your diagram correctly identifies the need for authentication, the ADK can also manage more complex flows, such as OAuth, as demonstrated in the A2A Auth Sample. [5]

Your initiative to build a hands-on project is an excellent way to learn! By aligning it with the ADK's RemoteA2aAgent and api_server tools, you can leverage the full power and simplicity of the framework. We welcome any further questions you have as you continue your experiments.