What Is Agent2Agent (A2A)?
Agent2Agent is how AI agents built by different vendors talk to each other.
Your Salesforce agent, your ServiceNow agent, and the agent your team built last quarter were made by different companies on different stacks. A2A is the common language that lets them coordinate anyway. It solves the problem that begins the moment you have more than one agent, which is now the normal case.
This post is the plain breakdown of what A2A is and where it stops.
What A2A Actually Is
A2A is an open protocol introduced by Google in April 2025 and placed under the Linux Foundation for open governance. It defines how independent agents discover each other, describe their capabilities, exchange messages, and hand off tasks across organizational and vendor boundaries.
It reached broad support quickly, with well over a hundred organizations backing it. Open governance matters here. A protocol for agents from different vendors only works if no single vendor controls it, which is why the move to a neutral foundation was the signal that A2A was serious infrastructure and not one company's feature.
The Problem A2A Solves
Connecting an agent to a tool was solved by the Model Context Protocol. Connecting an agent to another agent, built by someone else, was not.
Without a shared standard, every pair of agents needs a custom bridge, and the number of bridges grows faster than the number of agents. A2A gives agents a common way to work together, so coordination does not require a bespoke integration for every pairing. It is the horizontal problem, agents reaching across to peers, where MCP is the vertical problem, an agent reaching down to its tools.
How Agents Discover Each Other
A2A uses the idea of an agent card.
A card describes what an agent can do, so another agent can find it and delegate the right task to it. Newer versions add signed cards, cryptographic signatures that verify who issued the card and prevent forgery.
Discovery plus delegation is the core loop. One agent asks who can do this, finds a peer whose card advertises the capability, and hands off the work. The signing matters because a system that trusts agent cards has to know the cards are genuine, or the discovery mechanism becomes an attack surface.
MCP and A2A Are Not the Same Layer
This confusion is everywhere, so it is worth stating plainly.
MCP connects an agent to its tools. A2A connects an agent to other agents. A useful metaphor from the field is that A2A is the horizontal bus and MCP is the vertical bus. An enterprise agent uses MCP to do its own job and A2A to work with agents it did not build. They compose. They do not compete, and a serious deployment runs both.
What A2A Moves, and What It Does Not Preserve
A2A moves messages and task handoffs between agents. It does not guarantee that the meaning inside those messages survives intact.
When one agent delegates to another, the intent, the confidence, and the context behind the request can thin out in translation. The task arrives. The full meaning of the task may not, because the two agents rarely share a complete definition of the data they are passing. A2A was built for coordination, not for semantic fidelity, and those are different guarantees.
A2A and the Contract Layer
This is the layer I build.
CORDspec provides transport bindings over A2A, so when one agent hands a task to another, the meaning travels with it and the fidelity is measurable through the Envelope Fidelity Score. A2A gets the agents talking. CORDspec makes sure they understand each other.
Coordination without preserved meaning is just fast miscommunication, and in a system where agents act on what they receive, fast miscommunication is how a chain of agents produces a confident wrong outcome.
Where to Start
If you are deploying multiple agents, three moves.
One. Use A2A for cross-agent coordination rather than building custom bridges between every pair. The bridges do not scale.
Two. Treat agent cards as a trust boundary. Verify signatures. Discovery you cannot trust is a liability, not a feature.
Three. Add a fidelity layer over your A2A handoffs so the meaning of a delegated task is preserved and measurable, not just delivered.
A2A is how your agents become a team. The contract layer on top of it is how the team avoids confidently misunderstanding each other.
Structure before tools. Strategy before speed. Systems before scale.
The AI Operator Framework is the methodology for designing, governing, and scaling AI operations inside a business, including the data and citation fidelity layers most companies skip. Explore the full framework at JamilAshkar.com/framework. Start with the free course at JamilAshkar.com/course.
