Implement /agent-card endpoint presented in client.ts

[egor-baranov]

In file /samples/js/src/client/client.ts there are an agentCard method that triggers a GET request trying to retrieve this data. But from the server-side it's defined only in /.well-known/agent.json. So we need to additionally implement the same method through endpoint compatible with specification

https://github.com/google/A2A/blob/71b5a485a9cf844a531e8a8c821507d9358dd4b9/samples/js/src/client/client.ts#L362

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[olegchir]

Looks legit

[egor-baranov]

Doc string says

/**
   * Retrieves the AgentCard.
   * Note: The standard A2A protocol doesn't define a JSON-RPC method for this.
   * This implementation fetches it from a hypothetical '/agent-card' endpoint
   * on the same server, assuming it's provided out-of-band.
   * Caches the result after the first successful fetch.
   */

But there are no implementations to retrieve an agent card from /.well-known/agent.json. Should it be a distinguished method in API or there are need to be a custom implementation of AgentCard? I just don't see a point to have the same method which is provided from the agent.json out of the box. But not presented by an API client

Any thoughts on that?

[mbleigh]

I don't really understand what you're trying to do here - the spec specifies that /.well-known/agent.json is the discovery URL, there is no /agent-card endpoint as far as I know. Can you help me understand what part of the spec you feel is lacking and needs to be implemented here?

[holtskinner]

Please move this PR to the new samples repo here https://github.com/google-a2a/a2a-samples