[Feat]: Can we have multiple agents in a single A2A Server with different endpoints

[jebinj22]

Unable to add many agents in a single A2A Server

Scenario where i need it

• I am in a scenario that, in a server i need to host many agents. Can i have a feature to add multiple agents in a single server and port with different end points.
• Also if possible if there is a way to dynamically feed agent details to create agent and run in same server, same port with different end points.

Solution i suggest

• We might need to update the server, where A2AServer is defined in common/server file.

To complete the setup, please make sure to follow these steps:

1. Initialize the A2A server:

   server = A2AServer(
       host=host,
       port=port,
   )

2. Register each agent:

   server.register_agent(  
       endpoint="/agent-one",
       agent_card=agent_one_agent_card,
       task_manager=AgentTaskManager(agent=AgentOne()),
   )

Code of Conduct

• I agree to follow this project's Code of Conduct

[jebinj22]

To complete the setup, please make sure to follow these steps:

1. Initialize the A2A server:

   server = A2AServer(
       host=host,
       port=port,
   )

2. Register each agent:

   server.register_agent(  
       endpoint="/agent-one",
       agent_card=agent_one_agent_card,
       task_manager=AgentTaskManager(agent=AgentOne()),
   )

[jebinj22]

@andrewlarimer

I’m proposing this approach - do you think it’s reasonable to proceed with it?

If this is okay, we might need to update the documentation of A2A and other example program.

[pstephengoogle]

This is a common ask and we are working on the right approaches generally. In particular there are worries around the card/registry aspect. Proposal is upcoming for a registry service.

As for serving multiple agents from one service. There are multiple ways to achieve this. a2aproject/a2a-python#109 is a proposed PR to add this to the SDK

[satendrakumar]

@pstephengoogle I created an example project to run multiple agents on a single host. I’m not sure if this is the right approach. let me know your thoughts.

here is URL https://github.com/satendrakumar/a2a-multiple-agents-on-single-host

Does it make sense to add this to the a2a-samples code until it’s included in the a2a-sdk ?

[pstephengoogle]

Yes this is generally a good implementation of serving multiple agents from a single host. I think it would be good to include in the samples repo. It doesn't address the main issue, however, of the discovery of the agent cards for these (e.g. you would need to know the structure to find the cards). This is the area where a dedicated registry solution would address this. That is part of an ongoing discussion

[ognis1205]

FYI:

Well-known URLs like http://localhost:8000/a2a/conversation/.well-known/agent-card.json are invalid. These should be updated to use a usual API path instead.

#166 (comment)

[satendrakumar]

@ognis1205 Thank you for suggestion.
I’m not sure I fully understand your point, could you please clarify what exactly needs to be corrected?

Is your suggestion that the URL should be:
http://localhost:8000/a2a/conversation/.well-known/agent
instead of:
http://localhost:8000/a2a/conversation/.well-known/agent-card.json ?

I used this path to match our existing constant:
AGENT_CARD_WELL_KNOWN_PATH = '/.well-known/agent-card.json'.

[ognis1205]

Hi @satendrakumar .

Your endpoints for serving agent cards are defined here:

• https://github.com/satendrakumar/a2a-multiple-agents-on-single-host/blob/1f1cb5dd388f9259d4875b938c002c605ceec68c/main.py#L35
• https://github.com/satendrakumar/a2a-multiple-agents-on-single-host/blob/1f1cb5dd388f9259d4875b938c002c605ceec68c/main.py#L41
• https://github.com/satendrakumar/a2a-multiple-agents-on-single-host/blob/1f1cb5dd388f9259d4875b938c002c605ceec68c/main.py#L47

A well-known URL is a standardized location on a web server used to store information about the server itself, its services, or configurations.

According to RFC 5785 Section 3, the .well-known segment must appear immediately after the domain name and cannot have path segments before it.

This means URLs like:

http://localhost:8000/a2a/conversation/.well-known/agent-card.json

which contain path segments (a2a/conversation) before .well-known— do not conform to the well-known URI specification.

Instead, you could serve the agent card at a URL like:

http://localhost:8000/a2a/conversation/agent-card.json

It still doesn’t solve the main issue in either case — discovering the agent cards — since you’d need to know the path structure in advance, as @pstephengoogle pointed out.