Add A2A info

Author: johnsonr

README.md

@@ -48,6 +48,34 @@ When the Embabel shell comes up, use the story agent like this:
 x "Tell me a story about...[your topic]"
 ```
 
+Embabel integrates with the [A2A](https://github.com/google-a2a/A2A) protocol, allowing you to connect to other
+A2A-enabled agents and
+services.
+
+> Embabel agents can be exposed to A2A with zero developer effort.
+
+Check out the `a2a` branch of this repository to try A2A support.
+
+You'll need the following environment variable:
+
+- `GOOGLE_STUDIO_API_KEY`: Your Google Studio API key, which is used for Gemini.
+
+Start the Google A2A web interface using the `a2a` Docker profile:
+
+```bash
+docker compose up
+```
+
+Go to the web interface running within the container at `http://localhost:12000/`.
+
+Connect to your agent at `host.docker.internal:8080/a2a`. Note that `localhost:8080/a2a` won't work as the server
+cannot access it when running in a Docker container.
+
+Your agent will have automatically been exported to A2A. Add it in the UI, and start a chat.
+You should see something like this:
+
+<img src="images/a2a_ui.jpg" alt="A2A UI" width="600">
+
 ## Contributors
 
 [![Embabel contributors](https://contrib.rocks/image?repo=embabel/java-agent-template)](https://github.com/embabel/java-agent-template/graphs/contributors)