Join the discussion
Write your take first — we'll ask for email only when you're ready to publish.
- Hacker News
- A2A Protocol is directed at enterprises as is much of Google Cloud’s AI focus. They just renamed their AI suite “Gemini Enterprise Agent Platform” if you don’t believe me.
Enterprises have been sold on the idea of Agents talking to each other and performing collaborative work (replacing employees etc) so it makes sense.
From my pov nothing stops me from having a full blown agent _behind_ my MCP server.
So calling agent sees and MCP server, gets list of tools etc. The MCP server spins up an instance of relevant Agent and tells it to maintain state (if needed) as a key back to the calling agent’s MCP session_id.
Trivial stuff on Cloudflare
by holografix - Yes. My agent speaks A2A with itself and others. But my agent is built in layers like an organization.by reactordev
- Would love to hear more if you're interested in sharing.by chickensong
- Sure. We have completed the implementation. Each agent comes with a dedicated profile and social relations. Meanwhile, multi-agent chat and collaboration work perfectly with no need for @ tags.by ClawChat
- Ya, we tried it a bit, but have stayed with agent-behind-MCP style patterns for now. I think A2A or something like it will become a big thing as everything matures. It just felt over complicated for our use case. One misconception I had was we would just slap A2A on our existing agents and they’d work well together. Kind of dumb in hindsight.by time0ut
- All of this protocol crap is a distraction. What's important is allowing agents talk to each other in their current scope and ACLs, including for their ability to talk to and discover tools. When Anthropic decided MCP was a good idea and published what they did, I ranted for days. Ok, I'm still ranting.
Now, discovery is important and there is a post right now on the front page about it. But what everyone is probably missing is that a) agents with tokens and services that honor those tokens is already handled well with HTTP. Fun fact, the original HTTP protocol (does anyone do RFCs anymore?) didn't support POSTs! So, most calls can be boiled down to doing a GET request somewhere with a token the remote end understands. Layer on SSL to hide the ? parameters, assuming it's easy to get certs mapped to your house network.
Discovery can be handled a bunch of different ways but given the nature of where the agents are running, it can be DIFFICULT to connect them (hole poking comes to mind). Of course you could run stuff in the cloud. But, if you care about sovereignty, you probably want to avoid anything that will "lock" you into a service (or a single agent/model for that matter).
What's 100% missing is payments, of course. Meet the 402, PAYMENT REQUIRED. Cloudflare (grumble) has something for that, but they stole it from Lightning Lab's very own roasbeef's Aperture project a while back, which implements payments with the Lightning network.
Make a bulk payment to a Bitcoin address. Stuff it in a Lightning invoice, send it to someone, they extract it and update the server to let you in. If you decided they ripped you off, close the invoice and the funds are refunded.
Now, I know a lot of people are skeptical about Bitcoin, but I really do think micropayments are useful for agent-to-agent comms. That's why I threw down the idea on a page about two years ago...so I wouldn't' forget: https://ahp.nuts.services/
- Seems like over engineering just build an API in front of your agent, give the other agent the spec in a markdown file.by asdev
- why dropbox when you can just rsyncby pocksuppet
- On the vscode team we're rebuilding our agent infrastructure on top of a new protocol, AHP: https://github.com/microsoft/agent-host-protocol.
It's a common protocol for talking to a host of multiple agents/harnesses.
by roblourens - Related. Others?
The Agent2Agent Protocol (A2A) - https://news.ycombinator.com/item?id=43631381 - April 2025 (280 comments)
by dang - I am using A2A at work. It's a bit like the "microservices architecture" for agents... Allows you or teams to develop agents independently and have them interact as and when they need to. No major hurdles so far.by lazharichir
- This was my assumption. Agents will supersede services. There will be many companies way ahead of the curve and the rest of the industry will take 5-10 years to catch up.by asim
- Yes! Although I've created a number of open-source A2A packages (https://github.com/a2anet) so I'm a little biased. For a more objective view, I keep an eye on the A2A SDK's monthly downloads (https://pypistats.org/packages/a2a-sdk). They're at ~10.9M compared to MCP's 257M, so MCP is downloaded about 24x more than A2A.
A2A is much more popular in enterprise than startups. All of the cloud providers and enterprise orchestration platforms (e.g. Gemini Enterprise, AgentForce, watsonx Orchestrate, SAP Joule) support it. People in enterprise typically make their agents A2A compatible so they can use them on these platforms, share them with other teams, etc.
The startups that I have seen use A2A typically use it for at least one of the following reasons:
1. To standardise their API endpoints. A2A specifies how to send and receive text, data, and files, so they can write client code once and reuse it with different agent frameworks. 2. To standardise agent cataloging. A2A introduces the concept of an Agent Card which contains information about the agent like its name, description, skills, accepted input, etc. 3. For long-running tasks. A2A was explicitly designed for long-running tasks and supports polling, streaming, and webhooks.
Confusingly, none of the above use cases are necessarily agent-to-agent. Turns out to standardise agent-to-agent communication, discovery, and authentication, you need to standardise agent communication, discovery, and authentication.
The A2A protocol is a good (not perfect) solution for agent-to-agent communication and it will continue to grow. How much it grows depends on how agents evolve. At the moment companies are building MCP servers for coding agents and chatbots, but not agents themselves. I believe that companies will eventually start building agents to control and improve their customer's experience. If they do this, A2A is the natural choice because it solves all of the problems associated with discovering, connecting, and communicating with agents over the internet.
by benclarkeio - Not to great effect, AFAIK. Laurie Voss (creator of npm) had a good presentation a few months back on all the different agent interaction protocols, and was skeptical whether they (including A2A) added much value. https://youtu.be/kqB_xML1SfA?si=lxehX1-_z_dBoZtQby calny
- AI infrastructure/tools developer here (www.hic-ai.com). I considered the A2A protocol carefully, but I decided a while ago that, from my perspective, the A2A protocol was not solving the correct problem. There is no distinction (from the perspective of an agent) between a communication from Agent A to Agent B, on the one hand, and a communication from Agent A to "future Agent A", on the other. In fact, agents have no inherent sense of identity at all, so there is no inherent notion of a unique Agent A. The notions like "Agent A" received a message or that "Agent A" is sending a message to a different agent (or to its future self) are all inextricably intertwined with the idea of an agentic identity existing and being well defined in the first place, which it is not. The A2A protocol assumes the existence of such a well-defined agent identity in its presumption that agent cards point to a specific agent that can be discovered and deployed. I also think gRPC adds a significant layer of indirection and obfuscation, plus it's painful to implement. The lack of widespread adoption suggests that A2A is not really solving a real-world problem, compared to MCP, for instance.by simonreiff
- Agent identity is just OAuth in a fake mustache. I suspect the real boundary is not agent-to-agent, but context + permissions + audit trail.by pfannl
- We wouldn't have identities either if we were all clones and our memories could be edited and shuffled at each conversation.
For an agent to have an identity we would have to intentionally make it hard to context engineering and limit it to append only messages that mimick human communication.
I can implant a thought into your head. If I say "Don't think about a green elephant" for a moment you'll think about a green elephant. There are more sophisticated examples of a person implanting thoughts in somobodies head (e.g. propaganda) but that's about it, I can't literally edit thoughts.
Why on earth do we want to limit our ability to do more powerful context engineering in a substrate that offers that ability natively?
Presumably because for some use cases you want the context of an agent to belong to a different "administrative domain" and you so want to have control over what information reaches it and how can it affect it?
by ithkuil