MCP vs A2A vs ACP vs...
Comparing agent protocols
2025-05-23 MCP Summit
What are we
talking about?
12+ agent protocols
A disclaimer
What the **** do I know?
A quick plug
workflow_as_mcp(agent)
get_tools_from_mcp_url(url)An incredibly
useful paper
A Survey of AI Agent Protocols, Yang et al 2025
Protocols covered
- MCP
- A2A
- AC(onnect)P
- AC(ommunication)P
- ANP
- AITP
- Agora
- PXP
- LOKA
- CrowdES
- SPP
- LMOS
- AP
- WTF
- LOL
What is the vision?
What is the reality?
Taxonomy of agent protocols
What does Context-Oriented mean?
What does Inter-Agent mean?
Agents.json
./well-known ➡️ agents.json
A2A:
Agent to Agent Protocol
An inter-agent protocol from Google
A2A's perspective
Inter-agent is hard and MCP doesn't want that heat
ANP:
Agent Network Protocol
It's A2A but on the blockchain!
AITP:
Agent Interaction & Transaction Protocol
It's (also) A2A but on the blockchain!
ACP x2
- Agent Connect Protocol (Cisco)
- Agent Communication Protocol (IBM)
ACP:
Agent Connect Protocol
It's A2A but from Cisco!
ACP's perspective
You have to think bigger than MCP is thinking right now
ACP:
Agent Communication Protocol
It's A2A but from IBM!
Agora
It's neat!
Domain specific protocols
Human-Agent interaction protocols
- PXP
- LOKA
Robot-Agent interaction protocols
- CrowdES
- Spatial Population Protocols
LMOS:
Large Model Operating System
It's A2A but from IBM (again)!
Agent Protocol
It's agents.json (again)!
End of tour
"Within context-oriented interactions, interactive tools can be regarded as low-autonomy agents. Conversely, in agent-to-agent interactions, the communicating agents can also be viewed as tools with higher autonomy, designed to accomplish specific intelligent tasks."
– Yang et al (2025)
What MCP lacks
relative to other protocols
- Async?
- Renegotiation?
- ...?
MCP stands alone
in adoption
(Users') Attention Is All You Need
MCP plus...?
Does MCP need other protocols?
So MCP is perfect?
Nope.
A registry
I mean of course I think that.
Under construction!
A (better) authorization model
Reputation
What are "download counts" for an agent?
Let's find out what's next, together
You can follow me on BlueSky:
🦋 @seldo.com
MCP vs A2A vs ACP
By Laurie Voss
