It should be possible to host an A2A agent without the .well-known/agent-card.json URL

[darrelmiller]

a2a-dotnet/src/A2A.AspNetCore/A2AEndpointRouteBuilderExtensions.cs

Line 40 in aa35e9d

routeGroup.MapGet(".well-known/agent.json", async (HttpRequest request, CancellationToken cancellationToken) =>

Using .well-known/agent-card.json is optional, so we should either split this into a different Map call or provide a parameter to opt-in or opt-out.

My vote would be for a MapWellKnownAgentCard() method.

[clintwar]

In the same thought is any work planned for authenticated agent card as defined in the specification?

Question for you @darrelmiller if you are not having well known endpoint how are you standardizing on agent discovery? The specification has no standard beyond simple single agent per host via well-known which is rather limiting. Also how are you letting it be known what skills are available? You must be building some domain specific registry of agents? I wish they had a specification on agent registries. But then the A2A client is nonstandard meaning how does it work when needing to know how to discover agent capabilities when no well-known exists. Chicken/egg type of problems.

[brandonh-msft]

My vote would be for a MapWellKnownAgentCard() method.

Agreed, this is what another a2a client has done

[brandonh-msft]

how are you standardizing on agent discovery?

As you pointed out the spec doesn't so nor do we plan to (as far as I'm aware)

how are you letting it be known what skills are available?

This is part of the Agent Card definition; so agents report this as part of their card.

I wish they had a specification on agent registries.

As I understand it, this is a recent point of discussion on the spec, so may be "Coming Soon (tm)"

how to discover agent capabilities when no well-known exists. Chicken/egg type of problems.

Right, if you care about skills and are trying to use an agent that doesn't provide a card (i.e., the well-known endpoint) then you're kinda SOL and need to speak w/ the agent author :)

[clintwar]

And then in truly agentic experiences first your home or root agent must be formally told where the domain is of remote agents. Only to then ask the domain what the skills are. Now we need another layer of discovery, so maybe that is where the expansion in the specification on agent discovery beyond well known will go.

[brandonh-msft]

And then in truly agentic experiences first your home or root agent must be formally told where the domain is of remote agents. Only to then ask the domain what the skills are. Now we need another layer of discovery, so maybe that is where the expansion in the specification on agent discovery beyond well known will go.

yup who knows; right now we are merely an impl of the spec as-defined ;)

[SergeyMenshykh]

@darrelmiller, does the A2A spec actually say that the .well-known/agent-card.json is optional?

[clintwar]

@SergeyMenshykh the specification says you must provide an agent card, it does not say you must provide an agent card using .well-known uri. The words "if using" https://a2a-protocol.org/dev/specification/#53-recommended-location seem to suggest it is not required and thus optional.