Let’s get our hand dirty with an actual build. We will build and register an external AI agent, then walk through discovering, activating, and calling it directly from ServiceNow using A2A. Here's what you will learn: • Building the External Agent: A quick look at the flight agent built with Google ADK, exposed over an API, with Vertex AI doing the reasoning. • Turning On Discoverability: Flipping the setting in Agent Studio that lets ServiceNow reach agents registered outside the platform. • Registering the Agent: Adding the external agent as a new provider. • Reading the Agent Card: It’s a digital business card for the agent which has all the associated skills, connection details, transport protocol. • Discovery vs Execution Credentials: Two separate sets of authentication, one for finding the agent, one for actually running it. • The Connection URL Catch: Why the URL used to call the agent is not the same one used to discover it, and where that second URL actually comes from. • Live Test: Triggering the call, watching the orchestrator flag it as an external execution and getting real flight options back from an agent that was never built anywhere near ServiceNow. Blog: For a complete walkthrough of A2A concepts with respect to ServiceNow Action Fabric: https://www.servicenow.com/community/developer-advocate-blog/servicenow-action-fabric-a-detailed-walkthrough/ba-p/3581348 0:00 - Recap: MCP vs A2A 0:29 - Building the External Agent with Google ADK 1:01 - Setting Up Agent Discovery 1:53 - Turning On Discoverability in Agent Studio 2:47 - Registering the External Agent 3:37 - Discovery vs Execution Credentials 4:22 - Reading the Agent Card 5:32 - Activating the Agent and Skill Discovery 6:13 - Adding Authentication for Execution 6:36 - Connection URL vs Agent Card URL 7:21 - Live Test: ServiceNow Calls the External Agent