How to see the Agent Card ?

[ducknificient]

some simple question, the agent2agent protocol has agent card in /.well-known/agent.json , but how to access this in the adk web command ? from localhost:8000 .. thanks

regards,
duck

[Harshk133]

The Agent Card (agent-card.json) is a core part of the Agent2Agent (A2A) protocol and is used for agent discovery. How you access it depends on how you're running your agent.

1. Running with adk api_server --a2a

When you start an agent using the built-in API server with A2A enabled, ADK automatically generates and serves the Agent Card at the standard well-known endpoint.

For example:

adk api_server --a2a --port 8001

You can then access the Agent Card at:

http://localhost:8001/a2a/<your_agent_name>/.well-known/agent-card.json

Replace <your_agent_name> with the value specified in your:

Agent(name="your_agent_name")

configuration.

You can inspect it directly in a browser or with:

curl http://localhost:8001/a2a/<your_agent_name>/.well-known/agent-card.json

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2. Running with adk web

The adk web command launches the local developer UI (typically on localhost:8000). This interface is intended for development, testing, and orchestration, and does not itself host an A2A endpoint.

In this mode:

• Agent metadata is typically defined within your project structure (for example, via agent.json or agent-card.json files, depending on the project setup).
• The Developer UI can display interactions with remote agents and A2A handshakes through its tracing and inspection tools.
• If your agent connects to another agent using something like:

ClientFactory.connect("http://localhost:8001")

the underlying get_card() requests can usually be observed through the execution traces.

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Testing Agent Discovery

If your goal is to verify how another agent discovers your agent through the A2A protocol, the recommended approach is to run:

adk api_server --a2a --port <port>

and inspect the generated Agent Card at:

/.well-known/agent-card.json

This closely matches how agent discovery works in real A2A deployments.